Ghrelin regulates secretion and proliferation of the oviduct epithelial cells in vitro

Abstract

The aim of our in vitro experiments was to investigate the role of ghrelin (Ghr), a newly discovered metabolic hormone in control of proliferation (PCNA, cyclin B1), apoptosis (Bax, p53) and secretory activity (IGF-I and PGF 2α release) of bovine oviductal cells in vitro. The cells were isolated by flushing of the oviducts from slaughtered cows. The cells were pre-cultured in a basal medium (DME/F12 medium + 20% FCS + 1% antibiotic-antimycotic solution) to form a monolayer and then were incubated in presence of Ghr at doses of 0, 1, 10 or 100 ng/ml for 72 hours. Concentrations of insulin-like growth factor I (IGF-I) and prostaglandin F2α (PGF2α) in cell-conditioned medium were measured by IRMA/RIA kits. Indices of cell apoptosis (apoptotic peptides Bax and p53) or proliferation (the proliferation associated peptides PCNA and cyclin B1) in the bovine oviduct epithelial cells were analyzed by immunocytochemistry (ICC) and Western-blotting (WB). Obtained results show that Ghr stimulated the output of PGF 2α (at all tested doses; p< 0.05) and IGF-I (at 1 and 100 ng/ml; p< 0.05) by the oviductal cells. Ghr, given at all doses, increased the proportion of PCNA-positive cells (ICC, WB). However, the proportion of Bax-, cyclin B1- and p53- positive cells (ICC) was not changed significantly after addition of Ghr. These results clearly demonstrate that Ghr is a potent regulator of the secretory activity and proliferation in the oviduct epithelial cells. Elucidation of ghrelin role in apoptosis regulation within the oviduct requires further investigations.