Prenatal metformin treatment improves ovarian function in offspring of obese rats.

Maternal obesity causes a wide range of impairment in offspring, such as metabolic and reproductive dysfunctions. We previously demonstrated that female offspring of obese rats have increased serum estradiol levels during early postnatal life, probably because of decreased hepatic cytochrome P450 3A2 levels, which could lead to early onset of puberty and polycystic ovary condition in adulthood. Using metformin during pregnancy and nursing to improve the metabolic status of obese mothers could prevent the sequence of events that lead to an increase in postnatal serum estradiol levels in female offspring and, hence, reproductive dysfunction. We found that metformin prevented an increase in serum estradiol levels at postnatal day 14 in female offspring of obese mothers, which was associated with a restoration of hepatic cytochrome P450 3A2 levels to control values. Treatment using metformin could not prevent advanced puberty, but we observed that the number of antral follicles, follicular cysts and multi-oocyte follicles returned to control values in the female offspring of obese mothers treated with metformin. We also observed an increase in the levels of norepinephrine and the norepinephrine metabolite 3-methoxy-4-hydroxyphenylglycol in the ovaries, indicating increased sympathetic activity in female offspring induced by an obesogenic uterine environment. We found that this effect was prevented by metformin administration. From the results of this study, we concluded that metformin administration to obese mothers during pregnancy and nursing partially prevents ovarian dysfunction in female offspring during adulthood.