Society for the Study of Reproduction, Inc.
George Preti, Charles J. Wysocki, Kurt T. Barnhart, Steven J. Sondheimer, and James J. Leyden
Human underarm secretions, when applied to women recipients, alter the length and timing of the menstrual cycle. These effects are thought to arise from exposure to primer pheromones that are produced in the underarm. Pheromones can affect endocrine (primer) or behavioral (releaser) responses, provide information (signaler), or perhaps even modify emotion or mood (modulator).
In this study, we extracted underarm secretions from pads worn by men and placed the extract under the nose of women volunteers while monitoring serum LH and emotion/mood. Pulses of LH are excellent indicators of the release of GnRH from the brain’s hypothalamus. In women, the positive influence of GnRH on LH affects the length and timing of the menstrual cycle, which, in turn, affects fertility. Here we show that extracts of male axillary secretions have a direct effect upon LH-pulsing and mood of women. In our subjects, the putative male pheromone(s) advanced the onset of the next peak of LH after its application, reduced tension, and increased relaxation.
These results demonstrate that male axillary secretions contain one or more constituents that act as primer and modulator pheromones.
(Lake Worth, Fla.) — A study from two researchers in New Zealand theorized that a mother’s stress, mood disorders, or divorce may be related to their daughters’ earlier puberty. When they looked at 87 girls and their mothers, 67 of whom had mood disorders, their theory seemed sound.
While the study, which appears in the March/April issue of the journal Child Development, shows a correlation between mothers with mood disorders and their daughters’ earlier puberty, Bruce J. Ellis, PhD, one of the researchers, says that a direct cause and effect relationship cannot be shown.
“Both marital and family dysfunction and early pubertal timing in daughters may be caused by common underlying genetic factors,” he tells WebMD. Ellis is a lecturer in psychology at the University of Canterbury in New Zealand.
Breast Chemical: Sexual Desire Secret?
Breastfeeding mothers and their babies produce a chemical that can boost other women’s sexual desire, new research shows.
It’s a natural phenomenon found in animals — the production of chemicals called pheromones that regulate all sorts of reproductive behaviors and processes in other females, and possibly sexual desire, writes researcher Natasha A. Spencer, PhD, with The Institute for Mind and Biology at The University of Chicago.
The presence of women who are breastfeeding may be a signal to fertile women that they, too, support the demands of pregnancy and lactation, writes the author.
In a previous study, Spencer and colleagues reported that fertile women were dramatically affected — specifically a women’s period and the timing of ovulation was changed when exposed to these pheromones, she says.
But what about the women’s sexual desire and fantasies — the true measures of their motivation for sex? Will her partner benefit from her lust? If she has no partner, will she conjure up one through fantasy? That’s what Spencer’s study checked out.
Pheromones Trigger Sex Drive, Fantasies
In their study, Spencer and her research group collected the natural “breastfeeding compounds” from 26 mothers who wore pads in their nursing bras, where the saliva from their infants plus their own perspiration and milk was collected. They also wore underarm pads to collect perspiration.
The breastfeeding pads were then cut into pieces and frozen.
Then, 90 women between ages 18 and 35 — none of whom had given birth — were assigned to either the breastfeeding pads or a placebo pads group. They were asked to swipe the pads under their noses in the morning, at night, and when they wiped their upper lips, showered, or exercised during the day.
The women also tracked their lust; those with a sexual partner rated their sexual desire; they also recorded their sexual activity. Those without sexual partner recorded their moods and whether they had any sexual fantasies.
After two months of smelling pheromones from the breastfeeding mothers, women with regular partners showed a 24% increase in sexual desire, and women without partners had a 17% increase in sexual fantasies, she reports.
Among women who got placebo pads, those with partners had a slight decrease in sexual desire. Women without partners had a 28% decrease in fantasies.
“The effect became striking during the last half of the menstrual cycle after ovulation, when sexual [desire] normally declines,” says co-researcher Martha McClintock, PhD, a Distinguished Service Professor in Psychology at The University of Chicago, in a news release.
The phenomenon likely evolved in early primitive societies, when women produced children during times when food was plentiful. The pheromones would have been a way of encouraging other women to reproduce during this plentiful time.
In 1998, McClintock and her colleagues produced the first evidence of human pheromones. However, more research is needed to determine if the breastfeeding chemicals are indeed pheromones that trigger sexual desire, she adds.
Their paper on sexual desire appears in this month’s issue of the journal Hormones and Behavior.
Pheromones, those mysterious, scentless chemicals that some say drive human sexual behavior, have been studied for decades. But now researchers say they’ve finally found proof that mammals — such as humans and mice — are actually programmed to detect and use them.
A new study, published in the Sept. 5 issue of the journal Nature, shows the first real evidence that the nervous system of mice is wired to detect pheromones. And when that wiring is tampered with, their mating behavior is disrupted.
Researchers say mice contain pheromone receptors in a specialized organ in the smelling system of the body.
In their study, researchers at The Rockefeller University and the University of Maryland found that when these pheromone receptors were turned off through genetic mutation, the mice developed normally but were different in terms of aggression and sexual activity. The study authors say these differences might yield clues about pheromones’ role in influencing sexual behavior and species development.
For example, nursing female mice are normally aggressive toward other mice that invade their nest. But nursing mice without the pheromone receptors were less aggressive and slower to attack invaders.
Among male mice, researchers found several differences between the normal and genetically altered mice.
Sometimes, young, socially inexperienced mice exhibit sexual behavior toward other males until they learn to distinguish males from females. But the mutant males made fewer sexual advances toward males. Researchers say this could indicate that either the mutants are better at distinguishing between the sexes at an early age, or their overall sexual drive is reduced without the ability to detect pheromones.
In addition, mutant male mice tended to mount female mice fewer times than would otherwise be expected.
According to the authors, the existence of a functioning specialized pheromone organ in humans has been widely debated, and the role of pheromones in human behavior has yet to be clearly understood.
But since a functional role for this organ has now been shown in mice through genetic manipulation, they say the findings should stimulate more research into the counterparts of these genes in humans.
Switching Gene in Fruit Flies Makes Females Flirt Like Males
Flipping the switch on a single gene may be enough to turn a coy female fruit fly into a crooning Casanova, according to a new study.
Researchers found that altering a single gene in female fruit flies caused their sexual behavior to change and resemble that of males.
“In these experiments we see all the steps of the male courtship ritual you could physically expect a female fly to do,” says researcher Bruce S. Baker, professor of biology at Stanford University, in a news release. “It’s a male’s behavioral circuitry in a female body.”
Researchers say the results suggest that sexual behaviors that seemingly develop over time, like flirting and courtship rituals in flies and potentially in humans, may also have biological and genetic underpinnings.
NEW YORK (Reuters Health) May 08 – Lesbian women appear to process two putative pheromones in a manner that more closely resembles heterosexual males than heterosexual females, according to findings documented by positron emission tomography (PET) and MRI imaging during exposure to the agents, Swedish investigators report.
Dr. Ivanka Savic and her associates at the Karolinska University Hospital performed PET and MRI as subjects were smelling the progesterone derivative 4,16-androstadien-3-one (AND), which is found in human sweat at concentrations 10 times as high in men than in women, and the estrogen-like steroid estra-1,3,5(10),16-tetraen-3-ol (EST), which is detected in the urine of pregnant women.
The research team previously found that homosexual men responded more like heterosexual women than heterosexual men in PET scans of regional cerebral blood flow when smelling the two pheromones.
Areas of the preoptic and ventromedial hypothalamic nuclei were activated among homosexual men when smelling AND, a “pattern of activation that was reciprocal in heterosexual men.” Homosexual men responded to EST with activated olfactory regions, similar to reactions observed in heterosexual women.
For their current study, published in the May 8 online issue of the Proceedings of the National Academy of Sciences, Dr. Savic’s group performed PET and MRI for 12 lesbian women, 12 heterosexual women, and 12 heterosexual men as they smelled each of the two pheromones, odorless air, and four other ordinary odors.
The main finding was that “lesbian women differed from heterosexual women in that they did not activate the preoptic hypothalamus with AND.” The researchers also found that “lesbian women processed AND and EST more congruently with heterosexual men than heterosexual women.”
The lesbian women showed activation of the olfactory regions with both AND and EST, whereas among heterosexual women, only EST involved the olfactory regions, while AND showed activation of the preoptic hypothalamus.
Lesbians also exhibited partial activation of the anterior hypothalamus upon exposure to EST, which is the area of primary activation when heterosexual men smell EST.
None of the other odors exhibited differential activation in any of the study groups.
Dr. Savic’s team concludes: “The data support the notion of a coupling between hypothalamic neuronal circuits and sexual preferences and encourage further evaluation of the possible neurobiology of homosexuality and human sexuality in general.”
Proc Natl Acad Sci USA 2006
No Sex for Males Without Taste
For the first time, researchers have linked a specific sex behavior to a female insect pheromone.
If you haven’t yet heard of pheromones, rest assured that the perfume industry has. Pheromones are chemical signals exuded by many animals — including humans — that evoke behavior. Sexual behavior.
The trouble is, nobody is quite sure which pheromones do what. That is fast changing, although not as fast as some Internet perfume ads would have you believe. Why? Human sexual behavior is so complex that it’s hard to tease out one sex signal from another.
Fruit flies are a lot easier to understand. So Hubert Amrein, PhD, and colleague Steven Bray started there. They took a close look at fruit-fly mating behavior. It’s got six steps — and they have to be danced in exact order, although repetitions are allowed:
Then, Amrein and Bray took a closer look. Fruit flies, they knew, have taste buds on their legs. When they analyzed those taste buds, they found that the flies’ front legs had special taste buds. They acted as receptors for female insect pheromones. This means that when they taste the female insect pheromone, they send a chemical signal to the brain.
The researchers found the gene responsible for the special front-leg pheromone taste buds. Then they raised male fruit flies that lacked the gene. This meant they had no pheromone tasters on their legs.
The tasteless males tried to have sex. But when they got to step 2 — tapping the female’s abdomen — they stalled out. Unable to taste the female insect pheromone, they didn’t know to when to sing their mating song. They kept trying, but kept failing. Eventually, the females got bored and flew away.
What does this mean? It’s a sign that researchers are a step closer to decoding the chemical signals that make us want to act in certain ways. Perfume makers, stay tuned.
The findings appear in the Sept. 11 issue of Neuron.
Last year, crops losses of worth of Rs50,000 crore were estimated due to pests, weeds and diseases. The total losses that affect the crops produced in the country are more than 30 per cent from the pest’s attacks. Pests are affecting the standing crops of rice, sugarcane, pulses & wheat making the food grain production stagnant for last five years.
In India, consumption of pesticides is as low as 0.5 kg per hectare against Korea’s 6.60 kg per hectare and Japan’s 12.0 kg per hectare. According to the pesticides industry statistics, India spends $3 per hectare on pesticides compared with $255 per hectare spent by South Korea and $633 per hectare by Japan. Investing in pesticides gives the farmers more than five times of their return on the investment.
Many of the pesticides that farmers use for our crops have both environmental and health hazards. DDT, dioxin, HCH (hexachlorocyclohexane), and aldrin belong to the class of organochlorines. Almost every organochlorine studied has been linked to some environmental or human health harm. Most of these chemicals are banned in other countries and the rest are awaiting risk assessment reports before action can be taken but, they are still available in India and brought by small farmers because they are affordable.
Unlike conventional pesticides, there are chemicals known as pheromones which are safer mode of crop protection, that do not damage other animals, nor do they pose health risks to people. Pheromones lures and trap is an insect trapping apparatus which essentially works by using the sex pheromones generated by female insects to attract their male counterparts.
Pheromones specifically disrupt the reproductive cycle of harmful insects. In this way, farmers can reduce the amount of insecticide they need – spraying only when the insects are in a vulnerable stage or when their numbers exceed certain levels. There is no alteration to the natural biological and ecological cycle, hence ensuring that there is no environmental or health hazard. They are portable, less expensive and a more natural form of crop protection.
In 1987, Pest Control of India (PCI) became first company in India to commercially introduce pheromone technology for agricultural use by launching sex pheromone lures and traps for monitoring Helicoverpa armigera and Spodoptera litura. BCRL actively promoted the adoption of pheromones as monitoring tools, with a view to provide cost-effective and simple techniques to time application of biological control agents and bio-pesticides in IPM.
Since then in the past 17 years, PCI has introduced commercial pheromone lures for monitoring a range of pests including cotton bollworms, tobacco caterpillar, rice yellow stem borer, sugarcane borers, diamond back moth, brinjal shoot and fruit borer and fruit flies. PCI has also been regularly introducing suitable traps for use with these pheromone lures and today has in its trap range, funnel traps, delta traps, McPhail traps, cross-vane traps, water traps and bucket traps.
PCI has been working in the area of integrated pest management has even been awarded national award for R&D effort in agro and food processing industry by the Department of Scientific & Industrial Research (DSIR), recently in New Delhi.
This award recognizes PCI’s efforts in developing an effective control of sugarcane borer sex pheromones and an innovative trapping system, the Wota-TT, a portable water trap. PCI has also worked with national and international research organizations for synthesis and supply of lures for managing different noxious pests such as coffee white stem borer, coconut beetles and cocoa pod borer. Pheromones of several insect pests synthesized indigenously by PCI and traps are being sold within the country and also exported.
Because of its pioneering work in pheromone technology in agriculture under Indian conditions, PCI has been able to commercially introduce pheromone technology and has has the largest range of pheromone lures and traps, which are used in a range of crops and by farmers all across India.
Sensors in Nose May Sniff Sex Cues
WebMD Medical News
Reviewed by Louise Chang, MD
A second set of sensors in the noses of mice – and, perhaps, in humans — may be used to detect sexual cues rather than scents, and aid in the mating game, according to a new study.
Researchers at the Howard Hughes Medical Institute in Seattle, discovered the second set of sensory receptors in the nasal lining of mice.
They suspect these receptors detect pheromones — odorless substances linked to sexual behavior.
These same receptors are found in humans, mice, and fish. And genes similar to the ones that encode the mouse receptors are also found in fish and humans, the researchers say, raising the possibility human noses are also equipped with pheromone receptors.
Sensors to Sense Sexual Cues?
The unique receptors are called trace amine-associated receptors (TAARs) and are different than the ones that sense odors in mice, the researchers, including Stephen Liberles, say.
However, like receptors that pick up scents, the mouse TAARs are programmed to detect particular compounds.
In their study, published in the journal Nature, the researchers identified three receptors that recognized three different compounds in mouse urine. This suggests they play a role in detecting subtle chemical messages between animals.
One of the compounds was linked to stressstress.
The other two were generally found in higher concentrations in male versus female urine. One of those two is thought to be a pheromone that provides sexual cues affecting readiness for mating.
You’ve never heard of pheromones? Well, it’s time to learn about the part they play in your sex life, because it could be substantial. The concept of a human pheromone, or sexual scent of attraction, has been debated and researched for years.
In most animals, the relationship between pheromones and mating is straightforward. Sea urchins, for example, release pheromones into the surrounding water, sending a chemical message that triggers other urchins in the colony to eject their sex cells simultaneously.
Human pheromones, on the other hand, are highly individualized, and not always noticeable. In 1986 Dr. Winifred Cutler, a biologist and behavioral endocrinologist, codiscovered pheromones in our underarms. She and her team of researchers found that once any overbearing underarm sweat was removed, what remained were the odorless materials containing the pheromones.
Dr. Cutler’s original studies in the ’70s showed that women who have regular sex with men have more regular menstrual cycles than women who have sporadic sex. Regular sex delayed the decline of estrogen and made women more fertile. This led the research team to look for what the man was providing in the equation. By 1986 they realized it was pheromones.
There’s more on how pheromones affect women’s menstrual cycles. Think back to college, or to growing up if you had sisters. Most women who live with or near other women adjust their menstrual cycle timing to each other. A recent study at the University of Chicago by Martha McClintock exposed a group of women to a whiff of perspiration from other women. It caused their menstrual cycles to speed up or slow down depending on the time in the month the sweat was collected — before, during or after ovulation. This was the first proof that people produce and respond to pheromones.
Although it’s now clear that pheromones exist, the way our body processes them has yet to be determined. Animals have a vomeronasal organ (VNO), which perceives the substance and then leads them to mate. Some anatomists don’t think humans have a VNO; others think they’ve found pits inside our nostrils that might be VNOs, but may not work.
Implications for Fertility and Depression
Despite the gap in our knowledge, these remarkable studies about pheromones and menstrual cycles have brought to light the idea that pheromones could be used as fertility treatments for couples who want to conceive, or as contraceptives for those who don’t. And couples who are having sexual problems could use pheromones combined with traditional therapy to enhance desire. It’s also possible, some researchers say, that pheromones could be a mood enhancer, alleviating depression and stress. And the most far-reaching hypothesis so far is that pheromone treatment could control prostate activity in men to reduce the risk of cancer.
Subtle but Strong Influence
If you’re looking for the man or woman of your dreams, unsuspecting pheromones in your body scent are most likely playing a large and very clever role in mate attraction. According to an article in “Psychology Today,” how our body odors are perceived as pleasant and sexy to another person is a highly selective process. We usually smell best to a person whose genetically based immunity to disease differs most from our own. This could benefit you in the long run, making for stronger, healthier children.
Seventy-four percent of the people who tested a commercial pheromone called Athena, developed by Dr. Cutler, experienced an increase in hugging, kissing and sexual intercourse. Maybe the best advice to those looking for a mate or wanting to take their relationship to a new level is to take a good long sniff!
PHILADELPHIA — Scientists at the University of Pennsylvania and the Monell Chemical Senses Center in Philadelphia have found that exposure to male perspiration has marked psychological and physiological effects on women: It can brighten women’s moods, reducing tension and increasing relaxation, and also has a direct effect on the release of luteinizing hormone, which affects the length and timing of the menstrual cycle.
The results will be published in June in the journal Biology of Reproduction and currently appear on the journal’s Web site.
“It has long been recognized that female pheromones can affect the menstrual cycles of other women,” said George Preti, a member of the Monell Center and adjunct professor of dermatology in Penn’s School of Medicine. “These findings are the first to document mood and neuroendocrine effects of male pheromones on females.”
In a study led by Preti and colleague Charles J. Wysocki, extracts from the underarms of male volunteers were applied to the upper lip of 18 women ages 25 to 45. During the six hours of exposure to the compound, the women were asked to rate their mood using a fixed scale.
“Much to our surprise, the women reported feeling less tense and more relaxed during exposure to the male extract,” said Wysocki, a member of the Monell Center and adjunct professor of animal biology in Penn’s School of Veterinary Medicine. “This suggests that there may be much more going on in social settings like singles bars than meets the eye.”
After the women’s exposure to the underarm extract, further testing revealed a shift in blood levels of luteinizing hormone. Levels of this reproductive hormone, produced in pulses by the pituitary gland, typically surge right before ovulation but also experience hundreds of smaller peaks throughout the menstrual cycle.
Preti and Wysocki found that application of male underarm secretions hastened onset of these smaller pulses. Duration to the next pulse of luteinizing hormone was shortened by an average 20 percent, from 59 to 47 minutes.
Preti and Wysocki are now looking at the several dozen individual compounds that make up male perspiration to determine which may be responsible for the effects they observed. They also plan to study whether female pheromones can affect men’s moods or physiological functions.
“This may open the door to pharmacological approaches to manage onset of ovulation or the effects of premenstrual syndrome or even natural products to aid relaxation,” Wysocki said. “By determining how pheromones impact mood and endocrine response, we might be able to build a better male odor: molecules that more effectively manipulate the effects we observed.”
The underarm extracts used in the study came from men who bathed with fragrance-free soap and refrained from deodorant use for four weeks. The extracts were blended to avoid reactions to individual men’s odors. None of the women involved in the study discerned that male sweat had been applied right under their noses; some believed they were involved in a study of alcohol, perfume or even lemon floor wax.
Half the women received three applications of the male secretions during a six-hour period, followed three controlled exposures to ethanol, used as a control substance, over a six-hour period. For the other half, the regimen was reversed. The women did not report feeling any more or less energetic, sensuous, tired, calm, sexy, anxious, fatigued or active after exposure to male perspiration.
Preti and Wysocki are joined in the Biology of Reproduction paper by co-authors Kurt T. Barnhart and Steven J. Sondheimer of Penn’s Department of Obstetrics and Gynecology and James J. Leyden of Penn’s Department of Dermatology. Their work is sponsored by the National Institutes of Health.
Adapted from materials provided by University Of Pennsylvania.
You may remember the experiment in 1995 in which female (presumably heterosexual) college students were asked to rate the “pleasantness” of the smell of several unwashed T-shirts that had been worn for two nights by several different male students. It showed that the more different the woman and man were in their genes (in particuar, the ones that cause immune responses), the more “pleasant” she rated his T-shirt.
In other words, the less they both had genes that serve the protective function of causing immune responses, the more likely the woman would be sexually attracted to him. On average, heterosexual couples share only about 20% of their immune system genes. So, when it comes to immune system genes, opposites do attract.
More studies have occurred on related topics. Male odors that a heterosexual woman subconsciously recognizes may have a powerful effect on sexual attraction. In Psychological Science, Oct. 2006, researchers found that woman appeared happieset with their sex lives when their immune systems were not similar to those of their male partners. Women whose immune systems were similar to their male romantic partner’s were also more likely to have sex with other men — or at least to think about doing it.
The men and women in this study answered questions about their relationships. Each person rated their partner in terms of thoughtfulness, attractiveness, support, intelligence and other similar attributes. They also answered questions about their enjoyment of sex and their level of attraction to others.
There was no correlation between the immune system genes and the nonsexual factors of their relationship, but there was a correlation with the sexual factors. In fact, the greater the similar immune system genes, the greater the likelihood of dissatisfaction with the woman’s sex life with that partner.
Interestingly, there was no correlation between men’s gene and their enthusiasm for sex with the partner they had nor for interest in having sex with other women.
What might be driving the women’s response? The researchers speculate that women, on an unconscious level, may be seeking to produce healthy children and therefore respond to men with very different sets of genes from their own. Children with different sets of immune system genes may have a greater ability to fight off a wider set of diseases.
This “scent of a man” certainly is not the entire explanation for heterosexual women’s attraction, but it does offer an evoluationary perspective on some attractions that otherwise seem indescribable.