Category Archives: New Wave

You Don’t Know What You’ve Got

Every day my mind is blown by live broadcasts of astounding, weird creatures from our deepest oceans. I’ve posted a taste of this live stream video and photography extravaganza.

In the past, it’s been almost impossible to study life in the deepest oceans. Why? Because it’s freakin’ freezing (sometimes just above zero degrees centigrade (C) or 32oF by your U.S. thermometer), or boiling hot (60 to 464 °C), and the hydrostatic pressure is enormous, almost beyond comprehension. A fish, worm, or crab living down at the bottom of the sea is experiencing literally tons of pressure per square inch, like the weight of an elephant or an SUV compared to the 14.5 pounds per square inch you are probably experiencing right now. And yet, as we speak, heroic explorers are sending live stream video directly to you. And WOW! What they are seeing is beautiful and bizarre!

My colleague from the Lehigh University Department of Biological Sciences, Santiago Herrera, is the lead biologist on an expedition to the American Samoas to some of the deepest parts of the ocean, 3,000-5,000 meters, that is, about 2 miles under the sea. He’s now aboard the Okeanos Explorer, an impressive vessel equipped with high-tech lights, cameras, robot arms and scoops, and lasers that are sent to the sea floor and manipulated by the crew with precision. They broadcast live every day from their American Samoa Expedition.


Enter a caption

NOAA Ship Okeanos Explorer docked at the pier at the Port of Pago Pago in American Samoa. Significant outreach was conducted prior to commencing the expedition. Interviews were conducted with media, and ship tours were held for local elementary through college students, local partners, and government and agency representatives. Image courtesy of the NOAA Office of Ocean Exploration and Research, 2017 American Samoa.

Alien life on Our Own Plant

Just this week, the Okeanos Explorer crew sent these videos of Dr. Seuss-like creatures that you might think were discovered in outer space. What’s incredible is that these creatures’ habitat is actually the most common habitat on our planet. Santiago tells us that most of our planet consists of deep oceans (about 72%), and yet we know very little about what lives there.

Sex and Food Under the Sea

The other day, as I watched the Okeanos team zoom in on some rare sponges, sea anemones, and a type of deep water clam never-before-seen alive, Santiago explained that another extreme feature of the deep sea environment is very low fuel and nutrient availability. Most animals down there depend on a small, slow trickle of organic matter that floats down from shallow parts of the ocean. The link between food and sex holds up in these alien environments. Deep sea creatures must conserve energy and nutrients by maturing very slowly. In comparison to the willy nilly reproduction that’s going on up here, deep sea creatures engage in the energetically-expensive process of reproduction only rarely.

There are many other fascinating adaptations to the extreme deep sea environment. Cell walls and nuclear membranes of deep sea creatures are made to withstand enormous hydrostatic pressure, and therefore, if they are brought up from their deep sea habitat into lower pressures, they literally fall to bits. Many of these creatures are a deep red color, owing to high levels of hemoglobin. Hemoglobin is the thing in your red blood cells that makes them red, and the thing that transports oxygen to your various organs. Extra hemoglobin helps deep sea organisms survive in their low-oxygen environment. So, in the Okeanos Explorer videos, you will often see bright red shrimp, psychedelic ctenophores (comb jellies), and fiery-colored fish in the deepest waters. Here are some screen shots from their gorgeous website.

Kiss it Goodbye

Now that you’re amazed by and bonded to these fascinating friends, let me crush your soul. Climate change will have a devastating impact on our deep sea organisms, and this is related to the food-sex connection and the reality of trickle-down economics. The slow trickle of energy-yielding food to the lower depths has led to the evolution of animals that are now adapted to living on very little food and oxygen. They have survived and spread their traits to each generation because they have an innate tendency to grow and mature very slowly, and reproduce infrequently. Their habitat has been very stable for long periods of time, and once disturbed, they don’t appear to have innate mechanisms to make a comeback. Their rates of reproduction are too slow, and when they experience changes in the acidity, levels of oxygen, or temperature, their populations might not  recover. Climate change, global warming, whatever you want to call it, will cause these devastating changes that disturb the deep sea conditions. Scientists from Scripps Institute of Oceanography have published a study indicating that the food supply to some areas of the earth’s deep oceans will decline by up to one half by the year 2100.

It doesn’t appear that we can count on the United States to delay the onset of climate change. Think about it. Why do we need the governments to make us install solar, purchase electric vehicles, and recycle? When you are planning your own survival and that of your children and grandchildren, think of these deep sea organisms, and our native American friends at Standing Rock, and let them inspire you.

Please let me leave you with something better than a sad Joni Mitchell lyric (“You don’t know what you’ve got til it’s gone”). Keep learning, dig, dig, dig deeper than your initial shallow understanding. Acquiring knowledge is not elitist; it’s freedom and it’s fun. In the words of the B52s, There Goes a Sea Robin!

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Mystery Achievement (So Real)

There’s something strange about the world’s brightest women in science, technology, engineering, and mathematics (STEM) connecting around one common theme: their own personal insecurity. It’s even more remarkable when this unlikely point of connection propels them toward their career goals.

Assoc. V.P. Research and Professor at UCLA

Nancy Wayne, Assoc. V. C. of Research and Professor at UCLA

I experienced this first-hand in a workshop, “Women Advancing Together” sponsored by the Lehigh University’s Department of Biological Sciences and their National Science Foundation Advance Program. It was not unlike hearing women with anorexia nervosa lament their obesity. These women were the cream of their respective crops. They were top-tier university administrators and full professors with long lists of publications and grant proposals rated in the top 9% of those submitted. They were bright, young  assistant professors ranked above hundreds of applicants for the same job, and they were students ranked in the top of their graduating classes. Despite these credentials, they all shared similar stories of serious and even crippling crises of confidence, i.e., self-confidence. More important, I learned that if I stop writing here, or if you stop reading here, we might be part of the evil forces creating the problem. So, please, read on!

Something short of a miracle occurred when the women joined together in this workshop to confront their fears, embrace their true talents, and promote their own future success. This remarkable transformation was accomplished with the encouragement and guidance of the Associate Vice Chancellor for Research and Professor of Neuroscience at the University of California, Nancy Wayne. Thanks, Nancy!

The workshop started with the well-known, dismal statistics, but ended with a transformative twist. First, we were reminded that there is a substantial gender gap in STEM employment, a gap that grows from a crevice to a grand canyon at the ranks of full professor/senior scientist. Only 5% of full professors in engineering are women. Furthermore, there is a persistent wage gap; women who have landed STEM jobs are paid significantly lower salaries than men in the same position. Not encouraging news, but Nancy countered with evidence that low self-esteem is reversible.

Confidence in Women EngineersTo support this idea, Nancy showed that women who enter engineering fields have credentials and performance levels equal to those of their male counterparts, but the same women have lower levels of self-esteem and self-confidence correlated with stalled advancement. Another graph showed that, after taking an exam but before receiving their grade, those who underestimate their grade tend to be women, whereas those who overestimate their grade tend to be men. Still another graph showed that women negotiate their salaries far less than do men, and as a result, each individual woman stands to lose more than $500,000.00 in salary by the time they are 60 years of age. Nancy is in a good position to know that the wage gap is reversible because she has successfully corrected her salary and recovered her own lost wages. If this were the end of the workshop, however, the dismal statistics would persist far into the future.

Identity-Safe Environments Work for Women

The important twist in Nancy’s version of the story came when she showed her own published data that she collected while she was training women in medical school. She found that women trainees were less likely than their male counterparts to volunteer for leadership positions. More important, she showed that the trend is reversed by subtle suggestions to the contrary. Nancy documented a fact well-known to psychologists: crises of confidence are either averted by “identity safety” or exaggerated by “stereotype threat” (Davies et al., 2005).

Stereotype threat is the fear that an individual‘s performance will justify a negative stereotype of the group with which the individual identifies. This fear affects performance in a direction that supports the stereotype. A well-known example is that poor math performance occurs when girls are told that “girls are bad at math.” The good news is that the vortex of stereotype threat is not inevitable. The opposite occurs when girls perform math in an identity-safe environment, that is, they are told that girls and boys don’t differ in math ability. Is it a lie to say that girls and boys don’t differ in math? Not if the difference is ameliorated and girls math scores improve by telling that “lie.” The bottom line is, when the stereotype involves women’s identity, stereotype threat can be mitigated by the suggestion that women and men do not differ in their ability.

Women Advancing Together

After the data presentation, Nancy instructed the participants to break into groups of 5-8 for some guided discussion. She first instructed the groups to share a time when they might have experienced self-doubt or a case of “imposter syndrome” (wherein we fail to acknowledge our achievements and therefore fear that we might be exposed as frauds at any given moment). There was no hesitation here, and most women struggled to limit their story to one example. At my table, all of the women spilled out feelings of debilitating anxiety and loneliness as they faced career transitions. The intensity was magnified when women moved up and out, from different countries, cultures, socioeconomic backgrounds, or geographic regions within the same country. During this outpouring of emotion, the discomfort melted away. A reciprocal flow of intimacy, empathy, and support seemed to clear the way for strength and confidence.

After this critical step, the stage was set for the realization that we had all survived and made it through our personal trials. Nancy finessed the group onward to acknowledge and share our talents and skills. We were invited to answer the question “What are your strengths?” There was a moment of silence, and then another outpouring. The skill set at our table was formidable. These women were expert computer programmers, software engineers, chemical engineers, biomedical imaging experts, microscopists, architects, civil and mechanical engineers, teachers, writers, scholars, and facilitators of change. As each woman shared her journey, we all learned different ways of coping with self-doubt.

One fascinating comment came from the women who had grown up in China, where teamwork and humility are valued over individual achievement and self promotion. They said that, after living in the U.S. for a while, they decided to assume the very American idea of the “self made man.” It was funny to realize that this cartoon stereotype actually might be useful. Some prominent American males grow up with this “boot-strap” notion and tend to take it to mythological extremes, but in this case, it works as a tangible point of cross cultural exchange. Picking up on this theme, another woman shared her spin on the boot-strap idea from a classic book entitled “Composing A Life.composing a life Our relaxed, meandering conversation sparked a transformation. Whereas social forces had been conspiring to limit our individuality and advancement, our group forged a bond based on the idea that we can be the authors of our lives, lives that truly exists independent of persistent stereotypes, perceptions, and projections.

If we feel stupid, so what? In STEM, one useful strategy is to face the necessity of feeling stupid while we work at the frontiers of knowledge. By definition, a frontier exists beyond the limits of what is known. Scientists therefore must enjoy and seek out the opportunity to feel stupid because that feeling is the signal that you have found the end of what is known and have courageously leapt off the cliff into the unknown. Authoring new knowledge requires that you first recognize your authentic ignorance about the answer to an important scientific question. Your hypothesis may or may not be true, but there is no guarantee that it will be supported by your data. My own mentor used to say that “Your hypothesis was no less brilliant just because it turned out to be wrong.” There is no point in doing research on a documented fact. Engaging in the scientific process requires the strength to feel stupid until you collect enough data to support (or refute) your hypothesis.

At another table, it was noted that experience in athletics or gaming had provided a foundation for persistence and fortitude. Those of us who played softball know that if you strike out, you don’t quit, you simply step up to the plate in the next inning. There are always new innings, and even if you lose, there are more games, and even if you lose the championships, there will be more seasons. For other women, it helped in times of self doubt to remind themselves of the people who first believed in them, those who opened doors, and provided opportunities. They were buoyed by their fear of disappointing those people and propelled by their desire to prove those people right. Other strategies included sharing fears with supportive friends and reminding each other that stereotype threat can be averted when we establish an identity-safe environment.

A related problem is that traits valued in men are often less valued in women, and these traits are devalued in women by both men and women. In men, leadership qualities are seen as positive, whereas in women they are seen as bossy. Women who are direct, logical, clear, concise, and bold, are labeled “ice queens” or “bitches.” Some women at our table have come to accept that they are not well liked. Women who excel in their field will lose their high status in social circles built on gossip and shared failures, but in the end, this is a good thing. When women seek other women across the disciplines, they find their tribe. We got a taste of this in Nancy’s workshop. We saw that when women persist in their goals while feeling lost or stupid, and when they band together to support each other, the fears and anxiety dissipate, and talent and creativity take over. The best way to combat fears about losing friends and allies is to join forces with women who find themselves in the same dilemma. One of the most gratifying parts of the day came when the participants started trading contact information and making plans for future meetings and collaborations. We learned why Nancy Wayne names her workshops “Women Advancing Together.”

nancy wayne and jms

The best part of it all was knowing that Nancy Wayne and I have been advancing along with another workshop participant and Full Professor and Associate Dean, Jennifer Swann since the 1980’s. Jennifer and I both agree, our friendship with Nancy has been fantastic. Here are the three amigas at happy hour, listening to our science colleague, Assistant Professor Julie Miwa, jamming on the saxaphone and drinking to our mystery achievements.three amigas

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Sex and Food and. . . on the Table


oldie but goodie

“Sex and food and. . .” What pops into your mind to finish this sentence? For me it’s “rock and roll” (I substitute food for drugs because I don’t need drugs). If you are more punk than new wave it’s “Food, Sex, and Ewe,” and for the hip hopsters it’s “Sex, Food, and Sports.” The latter is also true for Seinfeld fans. Don’t Google “food and sex” though, you might get distracted.

“Sex-and-food” is the key to life. This grammatical impossibility stems from the fact that in the brain, the desires for sex and food seem to be one and the same, sometimes two sides of the same coin. In my upcoming book “Sex and food and. .” (Oxford University Press), I begin by noting that in every-day language food is sexy and sex is foodie;

“In both word and deed, we express our entangled appetites for food and sex, almost as if we confuse the two. In everyday language, food is sexy and sex is foodie. Chocolate is orgasmic and our lovers are delicious. In The Bible we are told to be fruitful and multiply. In Shakespeare’s Sonnet 118 he uses food metaphors for budding romance, for the “sweetness” of true love, and for the “bitter sauces” of infidelity.”

Just a smidgen of the evidence for the food-sex connection is presented in the table below. These 40-or-so chemical messengers have documented effects on ingestive behavior. They either increase or decrease the amount of food eaten per unit time. The same chemical messengers have clear, repeatable effects on reproductive processes, often including sexual desire and performance. In fact, compounds pushed as anti-obesity drugs by some researchers are being pushed as libido-enhancer by others. Our table reveals information useful for a wide range of scientists, not just those narcissists who feel that all research must have medical application. For more on this topic check out our new preprint now available online (it will be published open access).

TABLE 1. A list of hormones and neuropeptides that influence both food intake and reproduction. From Schneider et al., 2013, When do we eat? Ingestive behavior, survival, and reproductive success, Hormones and Behavior, published online ahead of print.

Central “Orexigenic” Peptides Ingestive Effects Reproductive Effects
agouti-related protein (AgRP), HS04, SHU9119 (MCR antagonists) increases food intake in fish (Schjolden et al., 2009), birds (Strader et al., 2003), and mammals (Rossi et al., 1998; Stark, 1998), and food hoarding in hamsters (Day and Bartness, 2004) inhibits gonadotropin secretion in fish (Zhang et al., 2012), inhibits LH in the presence of estradiol in female rats (Schioth et al., 2001; Watanobe et al., 1999), stimulates LH in male mammals (Stanley et al., 1999), ablation of AgRP gene restores fertility in ob/ob mice (Wu et al., 2012)
alarin Increases food intake in male rats (Van Der Kolk et al., 2010) stimulates LH secretion in castrated male rats (Van Der Kolk et al., 2010)
β-endorphin increases food intake in fish (de Pedro et al., 1995b) (reviewed in (Lin et al., 2000)), birds (Deviche and Schepers, 1984; Maney and Wingfield, 1998; Yanagita et al., 2008), and rats (Grandison and Guidotti, 1977; McKay et al., 1981) mediates stress-induced suppression of LH in fish (Ganesh and Chabbi, 2013), birds (Sakurai et al., 1986), inhibits LH secretion and sexual performance (Hughes et al., 1987, 1990; Sirinathsinghji et al., 1983), but might also increase sexual motivation in rats (Mitchell and Stewart, 1990; Torii et al., 1999),
galanin increases food intake in fish (De Pedro et al., 1995a; Lin et al., 2000; Nelson and Sheridan, 2006; Volkoff et al., 2005) and rats (Kyrkouli et al., 1990) stimulates LH secretion in birds (Hall and Cheung, 1991),  steroid-primed rats (Sahu et al., 1987)
galanin-like peptide (GALP) increases food intake in rats (Matsumoto et al., 2002), also decreases food intake in mice (Krasnow et al., 2003) stimulates LH secretion in male mice and rats and in estradiol-treated female rats (Krasnow et al., 2003; Matsumoto et al., 2001; Uenoyama et al., 2008)
gamma aminobutyric acid (GABA) might not mediate hyperphagic effects of orexin in fish (Facciolo et al., 2011); increases food intake in rats (Basso and Kelley, 1999) increases gonadotropin release in fish (Kah et al., 1992); GABA-BR decreases excitability of mouse GnRH-I neurons (Zhang et al., 2009); GABA-AR excitatory for mouse GnRH-I neurons (DeFazio et al., 2002; Moenter and DeFazio, 2005)
melanin-concentrating hormone (MCH) increases food intake in rats (Presse et al., 1996), but decreases food intake in fish (Shimakura et al., 2008) inhibits LH secretion in rats (Tsukamura et al., 2000a)
neuropeptide Y (NPY) increases food intake in fish (de Pedro et al., 2000; Lopez-Patino et al., 1999), frogs (Crespi et al., 2004), snakes (Morris and Crews, 1990), birds (Strader and Buntin, 2001), rats (Stanley and Leibowitz, 1984) and food hoarding in hamsters (Dailey and Bartness, 2009) increases gonadotropin release in fish (Peng et al., 1993), inhibits steroid biosynthesis in frogs (Beaujean et al., 2002), inhibits sex behavior in snakes (Morris and Crews, 1990), inhibits LH in the absence of estradiol, stimulates LH in the presence of estradiol in rats (Crowley et al., 1985; Sahu et al., 1987) (Sahu et al., 1987), inhibits sex behavior in rats (Ammar et al., 2000)
orexin/hypocretin increases food intake in fish (Lin et al., 2000; Volkoff et al., 1999; Volkoff et al., 2005), and rats  (Sakurai et al., 1998), but not in birds (da Silva et al., 2008) inhibits spawning in fish (Hoskins et al., 2008), inhibits LH in rats with little or no estradiol (Furuta et al., 2002), stimulates LH in rats with high  levels of estradiol  (Pu et al., 1998)
gonadotropin inhibiting hormone (GnIH) increases food intake in birds (Tachibana et al., 2005), mice, sheep, and monkeys (Clarke et al., 2012; Johnson et al., 2007; Tachibana et al., 2005) inhibits GnRH and LH secretion and sex behavior in fish (Moussavi et al., 2012), birds (Bentley et al., 2006; Satake et al., 2001) and blocks the LH surge in sheep and inhibits LH secretion in rats and female hamsters (Bentley et al., 2006; Johnson et al., 2007; Kriegsfeld et al., 2006; Smith et al., 2008)
Peripheral “Orexigenic” Hormones Ingestive Effects Reproductive Effects
corticosteroids chronically elevated levels increase food intake in fish (Bernier et al., 2004),  amphibians (Crespi et al., 2004), birds (Astheimer et al., 1992), and rats (Hamelink et al., 1994; McLaughlin et al., 1987; Stevenson and Franklin, 1970) inhibits a wide array of reproductive parameters in fish including parental behavior (Carragher et al., 1989; O’Connor et al., 2009) reviewed by (Milla et al., 2009), inhibits steroid synthesis and spermatogenesis in amphibians (Moore and Zoeller, 1985; Moore and Jessop, 2003), inhibits sex behavior in snakes (Lutterschmidt et al., 2004; Moore and Jessop, 2003), stimulates gonadotropin secretion at low doses in birds (Etches and Cunningham, 1976), inhibits HPG function at chronically high doses in birds (Etches et al., 1984), and mammals (Vreeburg et al., 1988)
ghrelin (gut) increases food intake in fish (goldfish and tilapia), but decreases food intake in rainbow trout (Jonsson, 2013; Jonsson et al., 2010), decreases food intake in birds (Kaiya et al., 2009), increases food intake in rats and mice (Tschop et al., 2000; Wren et al., 2000) and food hoarding in Siberian hamsters (Keen-Rhinehart and Bartness, 2005) stimulates LH release from fish (Grey et al., 2010), inhibits GnRH, LH secretion and sex behavior in rats and mice (Fernandez-Fernandez et al., 2004; Furuta et al., 2001; Shah and Nyby, 2010)
insulin (pancreas) chronically elevated levels increase body weight, adiposity, and food intake in birds (Nir and Levy, 1973), rats (Booth and Brookover, 1968; Friedman, 1977; Friedman et al., 1982; Houpt, 1974) systemic treatment inhibits LH secretion at doses that increase food intake in hamsters not allowed to overeat (Wade et al., 1991), inhibits LH secretion in sheep treated peripherally with saline but not with glucose (Clarke et al., 1990)
motilin (gut) increases food intake in fasted rats (Garthwaite, 1985) inhibits LH secretion in rats (Tsukamura et al., 2000b)
progesterone (gonads, adrenals) reverses the weight reducing effects of estradiol on body weight and food intake in rodents (Hervey and Hervey, 1966, 1969; Zucker et al., 1972) synergizes with estradiol to stimulate female sexual performance in rats (Dempsey et al., 1936), enhances estradiol feedback on LH in female rats (Chappell and Levine, 2000), mimics testosterone in male rats (Witt et al., 1995)
testosterone (gonads, adrenals) increases food intake and growth in rats (Siegel et al., 1981) stimulates sexual motivation in females (de Jonge et al., 1986; Everitt and Herbert, 1970) and sexual performance in male rats (Davidson, 1966; Davidson and Bloch, 1969)
Central “Anorectic” Peptides Ingestive Effects Reproductive Effects
α-melanocyte stimulating hormone (α-MSH), melanotan- II (MT-II), PT-141 decreases food intake in fish (Kang et al., 2011; Schjolden et al., 2009), amphibians (Carpenter and Carr, 1996), birds (Kawakami et al., 2000; Tachibana et al., 2007),  and rats (Vergoni et al., 1986), and food hoarding in Siberian  hamsters (Keen-Rhinehart and Bartness, 2007a; Shimizu et al., 1989) enhances electric organ discharge in  electric fish (Markham et al., 2009), Stimulates LH secretion and sex behavior in rats (Alde and Celis, 1980; Thody et al., 1981)
Cocaine and amphetamine-regulated transcript (CART) decreases food intake in fish (Volkoff et al., 2005), birds (Tachibana et al., 2003), rats (Kristensen et al., 1998) stimulates GnRH secretion in rats (Lebrethon et al., 2000; Parent et al., 2000)
Cholecystokinin (CCK) decreases food intake in fish (Himick and Peter, 1994; Volkoff et al., 2005), birds (Tachibana et al., 2012), rats (Gibbs et al., 1973) and food hoarding in Siberian hamsters (Bailey and Dela-Fera, 1995; Figlewicz et al., 1989; Teubner and Bartness, 2010) stimulates GnRH and LH secretion in rats (Ichimaru et al., 2003; Kimura et al., 1983)CCK in the medial preoptic areas is required for estradiol-induced lordosis in rats (Dornan et al., 1989; Holland et al., 1997)
Corticotropin releasing hormone (CRH) decreases food intake in fish (De Pedro et al., 1993; Matsuda et al., 2008), amphibians (Crespi et al., 2004), birds (Denbow et al., 1999; Furuse et al., 1997), rats (Heinrichs and Richard, 1999; Levine et al., 1983; Morley and Levine, 1982; Negri et al., 1985) and food hoarding in rats (Cabanac and Richard, 1995) reviewed by (Carr, 2002) inhibits spawning in fish (Mousa and Mousa, 2006), inhibits LH secretion and lordosis in rats (Olster and Ferin, 1987) and sex behavior in Syrian hamsters (Jones et al., 2002)
Dopamine (DA) decreases food intake in fish (Leal et al., 2013), rats (Heffner et al., 1977), increases food hoarding in rats (Borker and Mascarenhas, 1991; Kelley and Stinus, 1985), and reward (Wise, 2004) inhibits gonadotropin secretion in fish (Omeljaniuk et al., 1989), stimulates sexual arousal, motivation and reward in birds (Cornil et al., 2005), rats and hamsters (Agmo and Picker, 1990; Meisel and Mullins, 2006)
Glucagon-like peptide (GLP-I) decreases food intake in fish (Silverstein et al., 2001), birds (Tachibana et al., 2006), rats (Turton et al., 1996) stimulates LH secretion (Beak et al., 1998)
Gonadotropin releasing hormone (GnRH I or II) decreases food intake in fish (Hoskins et al., 2008; Nishiguchi et al., 2012), and female musk shrews (Kauffman and Rissman, 2004b) stimulates LH secretion in fish (Moussavi et al., 2012), birds (Chowdhury and Yoshimura, 2004), stimulates LH secretion and sex behavior in amphibians and reptiles (Alderete et al., 1980; Licht et al., 1984), rats and sheep and sex behavior in shrews and mice (Kauffman and Rissman, 2004a; Kauffman et al., 2005) (Temple et al., 2003) (Moss and McCann, 1975) (Clarke and Cummins, 1982)
Insulin-like Growth Factor -1 (IGF-I in CNS) ICV treatment decreases food intake in diabetic, but not normal rats (Lu et al., 2001), required for post-fast hyperphagia in rats (Todd et al., 2007) restores LH surge amplitude in middle-aged rats (Todd et al., 2010), required for the LH surge, estrous behavior, estrous cycles in rats (Etgen and Acosta-Martinez, 2003; Quesada and Etgen, 2002; Todd et al., 2007), and for sex behavior in rats (Etgen and Acosta-Martinez, 2003)
Kisspeptin decreases food intake in mice (Stengel et al., 2011) stimulates GnRH and LH secretion in fish (Moussavi et al., 2012; Tena-Sempere et al., 2012), stimulates testicular expression of ER-a in frogs (Chianese et al., 2013), rats (Gottsch et al., 2004; Irwig et al., 2004)
Norepinephrine decreases food intake in birds (Denbow, 1983) and stimulates food intake in rats (Ritter and Epstein, 1975) inhibits LH secretion in rats (Iwata et al., 2011), stimulates sex behavior in birds (Cornil et al., 2005) and rats (Nock and Feder, 1979)
Oxytocin decreases food intake in birds (Jonaidi et al., 2003), rats (Olson et al., 1991) stimulates GnRH and LH secretion sex behavior in rats (Rettori et al., 1997; Whitman and Albers, 1995)
Secretin decreases food intake in  rats (Cheng et al., 2011a) stimulates LH secretion in rats (Babu and Vijayan, 1983)
Serotonin (5HT) decreases food intake in birds (Denbow et al., 1982), rats (Blundell, 1977) stimulates LH in the presence of estradiol in rats (Coen and MacKinnon, 1979) Inhibits LH secretion in the absence of estradiol in rats (Coen et al., 1980) (Koh et al., 1984)
Thyrotropin releasing hormone decreases food intake in rats (Vijayan and McCann, 1977) and Siberian hamsters (Steward et al., 2003) stimulates LH secretion in pituitary in vitro not in vivo in rats (Fujihara and Shiino, 1983), and indirectly by effects on thyroid hormones in rats (Barrett et al., 2007)
Urocortin decreases food intake in fish, amphibians, birds, and rats (Spina et al., 1996) stimulates LH secretion in ewes (Holmberg et al., 2001), inhibits LH secretion in rats (Li et al., 2005; Nemoto et al., 2010), directly inhibits Leydig cell function in rats (Rivier, 2008)
Peripheral “Anorectic” Hormones Ingestive Effects Reproductive Effects
Adiponectin (adipocytes) decreases food intake in rats (Bassi et al., 2012), increases food intake in mice (Kubota et al., 2007), decreases body weight and increases energy expenditure, insulin sensitivity, and ffa oxidation without effect on food intake in rats (Fruebis et al., 2001; Qi et al., 2004) implicated in embryo implantation and fetal development in pigs and women (Palin et al., 2012), inhibits ovarian steroidogenesis in cows (Lagaly et al., 2008), inhibits GnRH and LH in rats and in GnRH cell cultures (Cheng et al., 2011b; Lu et al., 2008)
Adrenocorticotropic hormone (ACTH) decreases food intake in rats (Vergoni et al., 1986) stimulated LH secretion in female rats inhibits LH secretion in male rats (indirect via adrenals) (Mann et al., 1985; Putnam et al., 1991)
Bombesin (gut) decreases food intake in fish (Volkoff et al., 2005), birds (Savory and Hodgkiss, 1984; Tachibana et al., 2010), and rats (Gibbs et al., 1979) stimulates LH secretion in rats (Babu and Vijayan, 1983)
Cholecystokinin (gut) decreases food intake in fish (Volkoff et al., 2005), birds (Savory and Hodgkiss, 1984), and hoarding in Siberian hamsters (Gibbs et al., 1973; Qian et al., 1999; Teubner and Bartness, 2010) simulates LH secretion in rats (Perera et al., 1993); Inhibits lordosis duration in rats (Mendelson and Gorzalka, 1984), but see central effects in Table 1.1
Estradiol (gonads, adrenals, adipocytes, brain) decreases body weight and food intake in fish (Leal et al., 2009), lizards (Shanbhag and Prasad, 1992), obese but not lean hens (Jaccoby et al., 1995; Jaccoby et al., 1996), rats (Nunez et al., 1980; Roepke et al., 2010; Roy and Wade, 1977; Zucker, 1969) and food hoarding in Syrian hamsters (Klingerman et al., 2010) stimulates sexual receptivity and vitellogenesis and has negative feedback on LH in fish, frogs, lizards and birds (Chakraborty and Burmeister, 2009; Cheng, 1973; Crews, 1975; Gavaud, 1986; Gibbins and Robinson, 1982a, b; Licht et al., 1985; Liley, 1972; Mason and Adkins, 1976; McCreery and Licht, 1984; Redshaw et al., 1969; Shanbhag and Prasad, 1992; Yu et al., 1981), and stimulates LH surges in female rats (Chazal et al., 1974) and female sex behavior in rats (Dempsey et al., 1936; Powers, 1970), increases courtship and sexual behaviors in hamsters (Ciaccio and Lisk, 1973; Ciaccio et al., 1979; Takahashi et al., 1985)
Insulin (ICV treatment) decreases food intake in rats and baboons (Chavez et al., 1995; Woods et al., 1979) stimulates LH pulses in rats, pigs, and diabetic sheep and non diabetic ovariectomized sheep (Bucholtz et al., 2000; Cox et al., 1987; Daniel et al., 2000; Kovacs et al., 2003; Miller et al., 1995), inhibits LH in ad libitum-fed ovariectomized lambs (Hileman et al., 1993)
Insulin-like growth factor increases body weight gain at superphysiological concentrations (Gruaz et al., 1997) does not accelerate reproductive development in female rats (Gruaz et al., 1997)
Leptin (adipocytes, liver) decreases body weight, adiposity, and food intake in fish (Crespi and Denver, 2006; Murashita et al., 2008), and mice (Campfield et al., 1995; Halaas et al., 1995; Pelleymounter et al., 1995) and food hoarding in Syrian hamsters (Buckley and Schneider, 2003) while increasing energy expenditure mammalian leptin increases gonadotropin secretion in fish (Peyon et al., 2003; Peyon et al., 2001), delays the summertime regression of the testes in lizards (Putti et al., 2009), delays fasting-induced cessation of egg laying, follicular regression, and follicle wall apoptosis in chickens (Paczoska-Eliasiewicz et al., 2003), reverses the effects of metabolic challenges on gonadotropin secretion in mice (Ahima et al., 1996; Barash et al., 1996), estrous cycles, and steroid-induced sex behavior (the latter only in ad libitum fed female hamsters) (Schneider et al., 2007; Schneider et al., 1997; Wade et al., 1997)
Resistin transient decreases in food intake in rats (Tovar et al., 2005) promotes ovarian steroid secretion in rats (Maillard et al., 2011)

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Should I Stay or Should I Go?

Crawling C. elegans hermaphrodite worm

Crawling C. elegans hermaphrodite worm (Photo credit: Wikipedia)

             Should I stay or should I go? Well, how much food do you have? In some organisms, sexual desire is expressed by leaving, that is, by bidding adieu to a delicious pile of food and wandering off in search of a mate. But not just any mate, a mate with food! Lipton et al., at  Albert Einstein College of Medicine, use the “leaving assay” to measure male sexual desire. Their subject is the elegant, rod-like worm, Caenorhabditis elegans.*  They start by placing males on their preferred food source; then they measure how often males exit in search of mating partners. You can see the trails they leave in the substrate in this video of C. elegans appropriating Harlem art and culture.

              How do the researchers know “leaving” is a sex behavior? Context. Leaving a food source occurs only in a sexual context, and the leaving assay is being used to tease apart the threads that control the appetites for food and sex.

            First, a quick lesson in the fascinating sexuality of C. elegans. Males are not interested in other males, but they search intensely for a mating partner of the other sex. Note that I said “other sex” not “opposite sex.” There are no female C. elegans.  Males of this species mate enthusiastically with hermaphrodites. Hermaphrodites can, of course, self-fertilize, but sexual unions between males and hermaphrodites are far more fruitful than selfing. For hermaphrodites, mating with a male will produce more offspring, and for males, hermaphrodites are the only crying game in town.

            In the leaving assay, C. elegans males are placed on a preferred food source with or without hermaphrodites. Sexually mature males tend to linger when dining with hermaphrodites but leave readily when no hermaphrodites are present at the food source. They wander off searching for mates. The predilection is specific to sexually mature C. elegans, not to juveniles or males that have had their gonads removed.  It’s the gonads that put the lust in wanderlust. As sexy males’ bodies move through the substrate, they leave their snakey imprint, a permanent record of their search for the ideal dining experience. What is the ideal? A cozy little bistro with not only delicious cuisine but hermaphrodite companionship. What’s more, the hermaphrodites alone are not enough. Males prefer to stay and mate with hermaphrodites, but only hermaphrodites positioned at an abundant food source.

            The leaving assay in C. elegans is being used to tease apart the intricate threads that control the appetites for food and sex. Like our own appetites, those of C. elegans are sensitive to prior experience. Males that have been previously food-deprived have a longer latency to leave a food source. Hungry males will stay longer on a lonely, hermaphrodite-free food source before finally wandering off in search of a companion. The longer the food deprivation, the longer the males delay their wanderlust. These changes in the hunger for food and desire for sex may be mediated by some of the same hormones at work in our own species. Other researchers have shown that when members of C. elegans eat food, there is an increase in the secretion of serotonin. You’ve heard of it. Drugs prescribed for human depression target serotonin action. Prozac, for example, increases serotonin levels by blocking the reuptake of serotonin by the cells that secreted it in the first place. We have long known that depletion of serotonin is associated with anxiety and depression, and more recently it has been suggested that overeating foods that promote serotonin synthesis is a form of self-medication. Getting back to C. elegans, Lipton et al., found that mutations in the genes that encode serotonin receptors render the males insensitive to serotonin action. Mutant males that are insensitive to serotonin act like food-deprived males in that they fail to leave a food source in search of mating partners. There’s more. Mutations or other manipulations that inhibit gonadal function also act like food deprivation, i.e., they prevent wanderlust. Mutation of the fog-1 gene transformed males to females, that is, fog-1 mutants produced oocytes instead of sperm. Those males so transformed did not show the leaving behavior, but instead remained on food! This suggest that the chemical pathways that determine whether a young nematode develops into an adult male or a hermaphrodite also determine the leaving response to a food source.

            As I have noted in recent a review article (Schneider et al., 2012), most of the chemical messengers that increase the hunger for food inhibit sexual desire and ability. The reverse is also true. Chemical messengers that inhibit eating tend to increase sexual desire and ability.  The sheer number of these chemical messengers is mind boggling. The thought of unraveling the complexity of motivated behavior in vertebrates is overwhelming. On the other hand, the nervous system of C. elegans, a nematode worm, is comprised of only a few hundred neurons. The fact that they show quantifiable, goal-oriented decisions regarding food and sex is remarkable.

            Most investigators study food intake in animals (usually rats or mice) that are singly-housed and have little or no opportunity to move, let alone interact with potential mating partners. Most investigators that study reproduction do not observe their experimental subjects in the presence of food. The entire pharmaceutical-industrial complex is driven by theories derived from studying animals in these artificial environments. The knee-jerk assumption in obesity research is that chemical messengers like serotonin, leptin, and others function to keep body weight within some fashionable and “healthy” limit, and that this system has failed in over 60% of the population.  The work of Lipton is more in line with the idea that these chemical messengers function to orchestrate the appetites for food and sex in environments where energy availability fluctuates. For testing this idea, what system could be more elegant than that of C. elegans?

*its name is actually Greek and Latin for “recent, rod-like, elegant”

This is my favorite

C. elegans parody of that awful Harlem Shake video.

Lipton, J. Kleemann, G., Ghosh, R. Lints, R., Emmons, S. W. Journal of Neuroscience, 24 (34) pp. 7427, 2004.

Schneider J. E., Klingerman C. M. and Abdulhay A. (2012) Sense and nonsense in metabolic control of reproduction. Front. Endocrin. 3:26. doi: 10.3389/fendo.2012.00026.

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