In a breakthrough, scientists have discovered that male hormones can play an important role in female fertility and boost in vitro fertilisation (IVF) therapy.
Male hormones, or androgens, help drive the development of follicles - structures that contain and ultimately release an egg that can be fertilised by a man's sperm, a new study suggests.
Researchers believe the study provides potential biological targets to enhance fertility in women with diminished ovarian reserve, who produce few or no follicles in response to IVF drugs designed to boost follicle development.
"There is a raging debate in the reproductive endocrinology field about what male hormones are doing in female fertility," said Stephen R Hammes, senior study author and professor of Endocrinology at the University of Rochester School of Medicine and Dentistry.
"Our study doesn't solve the controversy, but, along with some earlier seminal studies from other groups, it does tell us that we can't dismiss male hormones. They might actually be doing something useful," said Hammes.
Using multiple animal models and cell experiments, Hammes and lead study author Aritro Sen, found that male hormones promote follicle development in two ways.
First, they prevent follicles from dying at an early stage. They do this by ramping up a molecule that stops cells from self destructing, a process called apoptosis.
Hammes and Sen speculate that if a woman doesn't have enough androgens (male hormones), more of her follicles may be dying and fewer progressing to a mature stage when they produce and release an egg.
Second, androgens make ovarian cells more sensitive to follicle-stimulating hormone or FSH, which promotes follicle growth.
They do this by creating more FSH receptors - molecules on the surface of ovarian cells that jumpstart the follicle making process in response to the hormone.
"Androgens are increasing follicle growth and ensuring follicles don't die - exactly what you want when providing fertility treatment," noted Hammes.
When the team administered small doses of androgens to mice that were taking the equivalent of medications given to women undergoing IVF therapy, they developed more mature, egg-containing follicles than mice that didn't receive androgens.
The androgen-treated female mice also released larger numbers of eggs with ovulation.
The study was published in the Proceedings of the National Academy of Sciences.
