Does Time of Exposure to Estradiol and LHRH Effect LH Release From Bovine Pituitary Cells?

Abstract

Time course of 17-.beta. estradiol [E2] and luteinizing hormone-releasing hormone [LHRH] effect on LH release was studied using bovine pituitary cells on day 5 of culture. LHRH at concentrations of 0.1, 1, 10 and 100 ng/ml increased LH in medium linearly with increasing log concentration of LHRH when present for .75, 1.5, 3, 6 and 24 h and the percent increase over controls was the same at each time period. In addition, E2 (present for 6, 12 or 24 h) at .5, 5, and 50 ng/ml also increased LH release linearly both in the presence or absence of LHRH. The stimulatory effect of LHRH on LH release from bovine pituitary is apparently consistant over 24 h and the stimulatory effect of E2 on both basal and LHRH induced LH release may be mediated at least in part directly on the pituitary.