A newly discovered line of communication between body muscle and the pituitary gland may play an unexpected role in female fertility, according to a new study.
McGill University researchers found that a protein produced in the muscles helps manage the release of a hormone made in the pea-sized gland attached to the base of the brain.
The findings, published in Science, could lead to new treatment options for infertility, the researchers said.
"Until now, it was not known that these two organs talked to each other or how they did so," said senior author Daniel Bernard, a Professor in McGill's Department of Pharmacology and Therapeutics. "This discovery opens up a new chapter in our understanding of the body and its complex connections."
How building muscle could backfire
The pituitary hormone studied, known as follicle-stimulating hormone (FSH), promotes the maturation of eggs in the ovaries. A deficiency can result in infertility.
The muscle protein - myostatin - acts as the body's natural brake on muscle growth.
Working with mice, the researchers found that lowering myostatin levels delayed puberty and reduced fertility. Restoring myostatin boosted FSH levels, but whether this can restore fertility is still under investigation.
Drugs designed to block myostatin, in order to build muscle, are being developed to treat conditions like muscular dystrophy. Drug companies are also testing whether blocking myostatin can help preserve muscle in people using GLP-1 receptor weight loss drugs, such as Ozempic, which can lead to both fat and muscle loss.
This study, however, raises concerns about the potential health risks of blocking myostatin.
"We found that experimental drugs created to treat muscle-wasting conditions lowered FSH levels in female mice. While these drugs may effectively grow muscle, there is a risk of disrupting reproductive hormones and fertility," said first author Luisina Ongaro, a research associate in Daniel Bernard's lab.
The breakthrough also opens the door to exploring whether natural variations in myostatin levels could explain the timing of puberty, missed periods in female athletes and infertility where no cause is apparent.
Moving forward, the researchers plan to test whether their results with mice apply to humans, a prospect they say is promising.
This study was supported by The Canadian Institutes of Health Research.
About the study
"Muscle-derived myostatin is a major endocrine driver of follicle-stimulating hormone synthesis" by Luisina Ongaro and Daniel Bernard et al., was published in Science.
