In Vitro Fertility Goddess.
Tuesday 2 September, 2008
Source: Nature Medicine Journal
A new study has found a "master switch" in the brain of mice that helps them control both fertility and body weight, helping to explain why some women who are too fat or too thin may have problems conceiving.
The gene, TORC1, acts as a switch by turning off appetite and allowing pregnancy.
The team of US scientists from the Salk Institute in California believe the gene may act to give an evolutionary advantage by stopping women getting pregnant in times of famine.
But what they discovered is that mice without the gene were infertile and grossly obese.
The study's author Marc Montminy says "the gene is crucial to the daisy chain of signals that run between body fat and the brain. It likely plays a pivotal role in how much we, as humans, eat and whether we have offspring."
Professor Montminy says that the gene is just as crucial as the appetite-regulating hormone leptin, which turns on TORC1 decreasing appetite and enabling reproduction: "Leptin tells the brain that times are good, your body is full, and that it is not necessary to eat more at the moment."
The researchers also argued that even a small mutation in the TORC1 gene might also play a role in obesity by failing to pass on the "stop eating" signal even when food is in abundance.
But more importantly, the failure of the gene to work properly could also affect fertility by not allowing reproduction to proceed.
The findings would facilitate the creation of a new drug which could act directly in patients lacking or with a dysfunctional TORC1 gene. "TORC1 is regulated by phosphate handling enzymes called kinases, and kinases often make for very good drug targets," Professor Motminy concluded.
Sarah Williams, IVF Goddess reporter
