In a pre-clinical study, a team of researchers have uncovered a new link between chronic stress and reproductive problem that shines the spotlight on a hunger-triggering hormone. High levels of the hormone ghrelin, which is released during stress and also stimulates appetite, could be harmful to some aspects of reproductive function.
Dr. Luba Sominsky, the senior co-author of the study, and Vice-Chancellor's Postdoctoral Research Fellow at RMIT, said that the research revealed the need for further study on the long-term impact of chronic stress on fertility and the role of ghrelin in regulating these effects.
According to Sominsky, the current findings, however, could have implications for those with underlying fertility issues, adding that stress is an integral part of human lives and most of us deal with it quite efficiently without significant health problems. She said that this means young and otherwise healthy women may experience only temporary and probably reversible effects of stress on their reproductive function.
Women that are already suffering from fertility problems, even a minor impact on their ovarian function may influence the chance and timing of conception. Sominsky said that although this work is exclusively in mice, there are many similarities to humans in stress responses as well as in many phases of reproductive development and function.
As a metabolic hormone, ghrelin triggers feelings of hunger, increases food intake, and promotes fat storage. It is also released during stress, and it is part of the reason for people to want to eat when they feel emotional or under pressure.
RMIT's neuroscientists have been exploring the role of ghrelin in healthy reproductive function and implications for fertility. This new pre-clinical animal study gave them the chance to investigate how ghrelin may have mediated the effects of chronic stress on the ovarian primordial follicle reserve.
Female mammals are born with a fixed number of these "immature" follicles which do not regenerate or regrow if they are damaged. Though the majority of primordial follicles will die and never complete their development, a small proportion will eventually develop further to become preovulatory follicles.
This analysis means the fewer "immature" ones the humans have, the fewer "mature" follicles later in life that can release an egg cell for fertilization. In this new research, it was discovered that female mice exposed to chronic stress has significantly fewer primordial follicles. Then, the team then blocked the effect of ghrelin on its receptor, and they found the number of primordial follicles was normal despite the exposure to stress.
Sominsky said that the length of the female reproductive lifespan is strongly linked to the number of primordial follicles in the ovary. And it is often predictive of earlier reproductive decline and deterioration by losing some of those primordial follicles early. Full study was published in the Journal of Endocrinology
