PROLACTIN-LIKE SUBSTANCE SECRETION BY GRANULOSA-CELLS ISOLATED FROM BOVINE OVARIES

By the 5-day culture of bovine granulosa cells both in serum-free and in serum-supplemented medium the time-dependent accumulation of PRL immunoreactivity was observed. FSH additions (10-10 000 ng/ml medium) led to a dramatical rise of immunoreactive PRL in a dose-dependent manner. LH stimulated the increase of PRL-like substance only in a great dose (10 IU/ml). Lower LH doses (0,01-1 IU/ml) had no significant influence on this process. Low doses of oxytocin (1 or 10 mIU/ml) blocked, and higher ones (100 or 1000 mIU/ml) stimulated the granulosa PRL-like substance accumulation. Arginine-8-vasopressin (1 - 1 000 ng/ml), arginine-8-vasotocin (10-10000 ng/ml), or LH-RH (10-10000 ng/ml)failed to influence the PRL immunoreactivity accumulation in the culture medium. Present data may suggest the production of PRL-like substance by bovine ovarian cells, as well as the involvement of gonadotropins and oxytocin in the regulation of this process.