Effects of growth hormone on female reproductive organs

During the last decade many experiments have been performed to study the effects of growth hormone (GH, somatotropin) on reproductive functions. Most of the studies found only slight or no effects of GH treatment, both on the oestrous cycle and on gonadotropin, progesterone. or oestrogen serum levels. In GH-treated animals, elevated levels of insulin-like growth factor I and GH in the serum could be correlated with an increased number of small (< 5 mm in diameter) ovarian follicles, possibly as a consequence of a reduction of apoptosis and follicular atresia. There is still controversy over the effects of GH on in vivo and in vitro embryo production and on the gestation period. Recent studies produced some evidence that GH-receptor is expressed in ovarian tissue, implying a direct role for GH in the ovary.