Direct action of growth hormone on bovine ovarian cells: effects on estradiol, oxytocin, vasopressin release by granulosa cells and on oocyte maturation and cleavage in vitro.

The influence of growth hormone (GH) (10-10,000 ng/ml medium) on the endocrine and generative functions of cultured bovine ovarian cells was studied. The release of estardiol, oxytocin, vasopressin by granulosa cells, as well as the nuclear maturation of oocytes ant their subsequent cleavage after in vitro fertilisation were analysed. GH stimulated the release of estradiol, oxytocin and vasopressin in a dose-dependent manner. The GH treatments during oocyte in vitro maturation had no marked influence on meiosis reinitiation, but significantly delayed its completion in a dose-dependent manner. These GH additions however did not change the ability of oocytes to cleave after in vitro fertilisation. Thus, GH may be a potent regulator of both the endocrine and generative functions of bovine ovarian cells.