According to a new study, a recently uncovered axis connecting muscles and the pituitary gland could play an unexpected role in female fertility.
Indeed, a research team from McGill University has discovered that a protein produced by muscles helps regulate the release of a hormone secreted by the pituitary gland, a pea-sized gland located at the base of the brain.
The research team members state that their findings, published in the journal Science, could lead to the development of novel treatment options for infertility.
"Until now, the dynamics of the relationship between the two organs, or even the existence of a link between them, were unknown," emphasizes Daniel Bernard, lead author and professor in the Department of Pharmacology and Therapeutics at McGill University. "This discovery marks an advancement in our understanding of the human body and its complex ramifications."
The counterproductive effect of muscle strengthening The pituitary hormone studied, called follicle-stimulating hormone (FSH), stimulates egg maturation in the ovaries. A deficiency in FSH can lead to infertility.
Myostatin, a protein produced by muscles, naturally inhibits muscle growth.
The research team found that a decrease in myostatin levels delayed puberty and reduced fertility in mice. Restoring normal myostatin levels caused a spike in FSH levels, but it is still being investigated whether fertility can be restored this way.
Myostatin inhibitors, designed to promote muscle growth, are being developed for the treatment of muscular dystrophy, among other disorders. Pharmaceutical companies are also examining whether these inhibitors can help preserve muscle mass in individuals who, for weight loss, take a GLP-1 receptor agonist, such as Ozempic, which may lead to the loss of not only adipose tissue but also muscle tissue.
However, the study raises concerns about the potential health risks of blocking myostatin.
"We discovered that experimental drugs developed for the treatment of amyotrophic disorders lowered FSH levels in female mice. While they may be effective in increasing muscle mass, these drugs could harm reproductive hormones and fertility," says Luisina Ongaro, lead author and research associate in Daniel Bernard's Laboratory.
This discovery paves the way for further research on natural variations in myostatin levels and their impact on the timing of puberty, menstrual cessation in female athletes, and idiopathic infertility.
For the research team, the next step will be to verify whether the results obtained in mice also apply to humans. The team sees this as a promising avenue.
This study was funded by the Canadian Institutes of Health Research.
Reference:
The article Muscle-derived myostatin is a major endocrine driver of follicle-stimulating hormone synthesis, by Luisina Ongaro, Daniel Bernard et al., was published in the journal
Science.