Researchers suggest that a hormone called kisspeptin could help to treat psychosexual dysfunction.
The hormone, called kisspeptin, was found to increase activity in areas of the brain normally stimulated by sexual arousal and romantic love.
Lead study author Prof. Waljit Dhillo, of the Department of Medicine at Imperial College London in the United Kingdom, and colleagues recently reported their findings in the Journal of Clinical Investigation.
Psychosexual disorder is a condition whereby an individual has difficulties becoming sexually aroused or feeling sexual satisfaction as a result of psychological issues, such as stress, anxiety, depression, a history of sexual abuse, or negative body perceptions.
Men with the condition may also have problems getting or keeping an erection, while women with the condition may be unable to achieve orgasm or experience pain during sexual intercourse.
Kisspeptin and its role in emotional behavior
According to Prof. Dhillo and team, psychosexual disorder is common among couples with infertility, who often experience stress and anxiety due to problems conceiving.
"Most of the research and treatment methods for infertility to date have focused on the biological factors that may make it difficult for a couple to conceive naturally," notes Prof. Dhillo. "These of course play a huge part in reproduction, but the role that the brain and emotional processing play in this process is also very important, and only partially understood."
The new study, however, suggests that an injection with the hormone kisspeptin has the potential to treat symptoms of psychosexual disorder.
Kisspeptin, also known as metastin, is a hormone produced by the hypothalamus. It prompts the release of two hormones - luteinizing hormone and follicle stimulating hormone - which leads to the production of the sex hormones testosterone and estradiol, a form of estrogen.
According to Prof. Dhillo and colleagues, studies have shown that kisspeptin is also present in other limbic regions of the brain, such as the amygdala, which are known to be involved in emotional and reproductive behaviors.
For their study, the team set out to investigate the role of kisspeptin in limbic brain regions. In particular, they wanted to determine whether the hormone influences emotional behavior in response to sexual stimuli.
Kisspeptin boosted activity in brain regions linked to sexual arousal
The researchers conducted a double-blind, placebo-controlled trial involving 29 healthy young men. Over two study visits, the men received an injection with either kisspeptin or a placebo.
After each injection, the men underwent functional MRI (fMRI), which enabled the researchers to monitor their brain activity as they viewed a selection of sexual and non-sexual images of couples.
When the men viewed sexual images, the team identified an increase in activity in brain regions that are usually stimulated by sexual arousal and love following the kisspeptin injection, but not after injection with the placebo.
The researchers say that these findings indicate that kisspeptin enhances behavioral circuits in the brain that are related to sex and romantic love - a finding that could lead to new treatments for psychosexual disorder.
"Our initial findings are novel and exciting as they indicate that kisspeptin plays a role in stimulating some of the emotions and responses that lead to sex and reproduction.
Ultimately, we are keen to look into whether kisspeptin could be an effective treatment for psychosexual disorders, and potentially help countless couples who struggle to conceive."
Prof. Waljit Dhillo
Reductions in negative mood with kisspeptin injection
Furthermore, the researchers say that their findings could also pave the way for new treatments for depression.
When the men were shown fearful images, the team found that the kisspeptin injection boosted activity in brain regions involved in regulating negative moods. Such activity did not occur in response to happy or neutral images.
Additionally, the men who received kisspeptin reported a decrease in negative mood in questionnaires they completed after fMRI.
"Our study shows that kisspeptin boosts sexual and romantic brain activity as well as decreasing negative mood," says first author Dr. Alexander Comninos, also of the Department of Medicine at Imperial.
"This raises the interesting possibility that kisspeptin may have uses in treating psychosexual disorders and depression which are major health problems which often occur together, but further studies would be needed to investigate this."