Kisspeptin, a hormone involved in reproduction, may also regulate sex drive in men.
Scientists know that a hormone called kisspeptin has a role in the production of sperm and eggs. Now, researchers at Imperial College London in the United Kingdom have done a new study, published October 18 in the medical journal JCI Insight
The study investigated how kisspeptin behaves in the brains of healthy volunteers.
'Kiss' Hormone Was Discovered in Hershey, Pennsylvania
Kisspeptin, so named because it was discovered by researchers in Hershey, Pennsylvania, the home of Hershey’s Kisses, is called the “master regulator” of reproduction because earlier research has shown that it interacts with other brain chemicals to have a central role in orchestrating reproductive, behavioral, and metabolic control of reproduction.
In the small study, conducted in London, 29 healthy men received kisspeptin intravenously while in an MRI scanner, allowing the researchers to look at their brain activity while they were taking the hormone. While in the MRI scanner, the participants were shown sexual images, negative images (a car crash), and neutral images (a cup), and the researchers monitored their brain activity while they looked at the images as well as while their brains were at rest (not looking at any images).
Study Compared Normal Brain Behavior With Behavior While Exposed toKisspeptin Hormone
As part of the study, the participants also filled out questionnaires that included questions on sexual aversion (sexual aversion disorder is a psychiatric diagnosis defined as “persistent or recurrent extreme aversion to, and avoidance of, all or almost all, genital sexual contact with a sexual partner" that causes distress or interpersonal difficulty). The participants also had scans and filled out questionnaires while getting a placebo IV infusion instead of kisspeptin, but they did not know which they got during the testing. The two methods allowed the researchers to compare normal brain activity and behavior with their responses while getting the hormone.
After studying the results, the researchers made these findings:
- Kisspeptin altered activity in specific resting brain networks, and an increase in this activity was linked to less aversion to sex and greater brain activity in areas involved in sexual arousal.
- Specifically, the hormone altered activity in the default mode network and salience network, which have key roles in social and emotional processing.
- Kisspeptin increased key mood connections in the brain, which increased activity in key mood centers when presented with negative images such as those of car crashes.
- Kisspeptin decreased negative mood
Study Adds Science to What Experts Know Clinically
Kenneth Paul Rosenberg, MD, a psychiatrist based in New York City and the author of Infidelity, Why Men and Women Cheat,
Studying the Brain’s Resting State for Clues AboutTreating Conditions Such as Low Sex Drive
The researchers explain that resting brain activity is the state our brain enters when not concentrating on a task, like a car in neutral. Studying the neutral resting state is critical for understanding what happens when the brain is active, and studying the resting brain allows scientists to examine large brain networks they know are abnormal in various psychological disorders to see if certain hormones or drugs can affect them. “Although we have previously investigated how this hormone affects the brain when it is in an active state, this is the first time we've demonstrated it also affects the brain in its baseline resting state. These insights suggest [that] the hormone could one day be used to treat conditions such as low sex drive or depression,” says Waljit Dhillo, PhD, the head of endocrinology and investigative medicine at Imperial College London and senior author of the study.
A Possible Avenue for Treatment of Psychosexual Problems
"Our findings help unravel the many and complex roles of the naturally occurring hormone kisspeptin, and how it orchestrates reproductive hormones as well as sexual and emotional function,” says Alexander Comninos, MBBS, PhD, a consultant in diabetes and endocrinology at Imperial College Healthcare in the United Kingdom and the first author on the Kisspeptin study. “Psychosexual problems, such as low sex drive, affect up to 1 in 3 people and can have a devastating effect on a person's, and a couple's, well-being. These findings open avenues for kisspeptin as a future treatment for these problems, although there is a lot of work still to be done."
Dr. Comninos says that the new study expands information about the hormone: “Our findings suggest it can actually influence entire networks in the brain even when we are not doing anything, and this is linked to subsequent sexual and emotional function. Taken together, these findings provide the scientific basis to investigate kisspeptin-based treatments in patients with psychosexual and mood disorders, which are both huge health issues and frequently occur together.”