The estimation of bovine growth hormone (bGH) preparations of cultured homologous cells isolated from female reproductive system

The aim of our study was to develop a reliable and sensitive method to estimate the biological activity of different preparations of growth hormone before its practical application. We investigated the effect of additions of bovine growth hormone (bGh, at doses of 0, 0.001, 0.01, 0.1, 1 and 10 microgram/ml incubation medium) on production of insulin-like growth factor I (IGF-I), insulin-like growth factor binding protein-3 (IGFBP-3), progesterone, estradiol, cyclic adenosine monophosphate (cAMP) and prostaglandin F-2 alpha (PGF-2 alpha) by bovine ovarian granulosa and oviduct epithelial cells. It was found that bGH significantly (P less than 0.05) stimulated IGF-I, IGFBP-3, progesterone, estradiol, cAMP and oxytocin release by bovine granulosa cells (Table 1). Maximal response of granulosa cells to bGH addition was observed in increase of oxytocin (242% over control), cAMP (69.7%), IGF-I (62.7%) and estradiol (60.3%) output. The influence of bGH on IGF-I, cAMP, estradiol and progesterone release had biphasic manner with maximal response at bGH doses of 0.1-1 ug/ml medium. bGH stimulated oxytocin output in a dose-dependent manner with maximal response at supraphysiological dose (10 ug/ml), whilst stimulating effect of bGH on IGFBP-3 release was almost similar at all the doses tested. bGH stimulated also IGF-I and cAMP production by oviduct epithelial cells in a biphasic manner with maximal effects at 0.001, 0.1 ug/ml or 0.01 ug/ml media resp. (Table II). Addition of bGH to culture medium caused the inhibition of PGF-2 alpha production with near similar effect at all doses tested. The present observations suggest involvement of GH in control of animal ovarian and oviductal secretory activity. It was demonstrated that cells isolated from bovine reproductive organs can be used for evaluation of biological activity of homologous GHs. Secretion of IGF-I, oxytocin, cAMP and estradiol by granulosa cells or IGF-I by oviduct epithelial cells can serve as most proper indices of biological activity of GH preparations to be tested