Published October 10, 2014
Previous research shows that the hormone oxytocin stimulates social behavior in humans, but a study published Thursday in the journal Cell suggests the hormone plays an especially strong role in regulating female sexual behavior.
Scientists at The Rockefeller University in New York City genetically modified female mice so that they no longer had an oxytocin response in the prefrontal cortex. As a result, the females no longer approached male mice for mating during the sexually receptive stage of their estrous cycle. In fact, with reduced oxytocin, the female mice showed about as much interest in males as they did in a LEGO block.
The researchers manipulated only a small amount of the neurons— less than 1 percent in the prefrontal cortex, an area known to trigger behavior in mammals, lead author Miho Nakajima, a graduate student at The Rockefeller University, told FoxNews.com.
Senior study author Nathaniel Heintz, a James and Marilyn Simons professor at The Rockefeller University, said the female mice were still interested in males and other females when oxytocin was reduced, but they didn’t show sexual interest.
“When [female] mice are sexually active, this small population [of neurons] is required for female mice to show interest in the male mice,” Heintz, an investigator at Howard Hughes Medical Institute, told FoxNews.com.
Researchers found that the change in interest among the male mice was less pronounced than the females’ response when researchers manipulated their oxytocin levels.
“There’s a functional difference in how male mice and female mice responded,” Heintz said.
Past research has shown that oxytocin plays a strong role in partner and mother-child bonding.
A study previously published in the journal Psychoneuroendocrinology showed that oxytocin levels skyrocket when people fall in love, and that a higher amount of oxytocin is correlated with longer relationships. Another study, in the journal Social Cognitive and Affective Neuroscience, suggested that oxytocin improved communication and lowered cortisol, a stress hormone, in both men and women. Many scientists have consequently nicknamed oxytocin the “love” or “pro-social” hormone.
The study authors said further research should explore what oxytocin does at a molecular level, and which brain areas and what types of cells respond to the hormone. Their study explores how oxytocin behaves in just one context.
Other studies have examined whether oxytocin levels can be modified to enhance the social behaviors of people with autism spectrum disorder (ASD). The mental condition impacts 1 in 68 children, and its hallmark is impaired social interaction.
Heintz said his team’s findings could help advance treatment development for ASD.
A study published last year in the journal Proceedings of the National Academy of Sciences suggested that a single dose of oxytocin can increase brain functions responsible for social interaction in children and adolescents with autism. In their research, Yale University scientists found that brain centers associated with reward and emotional cognition responded more during social tasks when the study participants were giving an oxytocin nasal spray rather than a placebo nasal spray.
“Each study gives us more insight into how this [oxytocin] might be acting in humans,” Heintz said.