Researchers at the University of Gothenburg have identified the biological clock that governs female fertility. This discovery could be of great significance for future medical treatment of female infertility.
There are women who can give birth to healthy children at 50 years of age, while there are those who are unable to become pregnant when they are 30. The question is, why is this so? Part of the answer is that a woman only has a given number of eggs, and the time when these run out determines the time when the woman enters the menopause.
Up to now, we have known very little about the biological clock that governs female fertility, but a new study at the University of Gothenburg is pointing to a solution of the mystery. In just the same way that newborn babies are put into the care of nurses, human eggs need support and nourishment from the somatic cells surrounding them. This latest discovery by Professor Kui Liu’s research group shows that a signalling pathway in these somatic cells plays a key role in controlling the survival of these immature eggs.
The mTOR signalling pathway in the somatic cells, which are also known as primordial follicle granulosa cells (pfGCs), is necessary for activating the expression of the kit ligand growth factor. Kit ligand in turn then binds to the kit receptors of the eggs and thus determines the eggs’ fate. “This regulation and control as exercised by the somatic cells over the eggs determines when the eggs start to grow and when they die, and thus act as a biological clock that determines the start of the menopause,” says Professor Kui Liu, who is affiliated with the Department of Chemistry and Molecular Biology.
The discovery has been published in ‘Current Biology’. The hope now is to be able to help infertile women whose eggs are unable to mature. Our increased knowledge about the molecular mechanisms that govern the eggs’ development means there is greater hope that these discoveries can be applied to the clinical treatment of female infertility in the years to come. This is something that Professor Liu’s group will be addressing in the future. “I believe that in only 5-10 years’ time this new knowledge can be applied to clinical treatment for infertile women,” Kui Liu says.