Researchers at the University of Maryland School of Medicine have discovered that adult male sexual behavior in rats is determined by the actions of signaling molecules called prostaglandins that wire the developing brain for sexual behavior. Their study, published in the journal Nature Neuroscience, is the first to link prostaglandins to brain development and the first to identify its role in the masculinization of sexual behavior.
“If you stop the production of prostaglandins just before birth and just after birth, you erase adult male sexual behavior,” says Margaret M. McCarthy, Ph.D., professor of physiology at the University of Maryland School of Medicine and the study’s primary investigator. “Without prostaglandins during brain development, male rats do not develop the brain wiring necessary to respond to testosterone as adults,” explains Dr. McCarthy.
Researchers used non-steroidal anti-inflammatory medications such as aspirin to interfere with prostaglandins during this critical period of brain development. “The study raises the possibility that non-steroidal anti-inflammatory drugs, taken during pregnancy, might affect sexual differences in the brains of humans,” says Dr. McCarthy. The study does not address sexual preference and does not suggest a possible explanation for homosexuality in humans.
Prostaglandins are involved in the regulation of many bodily functions and responses, including childbirth, inflammation, pain and body temperature. “We believe prostaglandins also act to organize neural structures that control male sexual behavior,” says Dr. McCarthy.
Researchers used anti-inflammatory drugs to inhibit prostaglandins in pregnant rats during the last week of gestation and the first week of lactation. Rats who received low doses of aspirin in their drinking water produced male offspring with mildly impaired sexual behavior. Newborn male rats treated directly with indomethacin, a potent anti-inflammatory drug, were completely asexual in adulthood.
The study shows the link between prostaglandins, early brain development and sexual differentiation in rats, but Dr. McCarthy says the findings may or may not apply to humans. “Human sexuality is much more complex and there have been no previous studies to link exposure to prostaglandins in utero to human sexual functioning,” she says.
The data published in this study was the doctoral thesis work of Stuart Amateau, a M.D./Ph.D. student in the Program in Neuroscience at the University of Maryland School of Medicine.
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