Prostaglandin E2, prostaglandin F2 alpha and endothelin-1 production by cow oviductal epithelial cell monolayers: Effect of progesterone, estradiol 17 beta, oxytocin and luteinizing hormone

The optimal oviductal environment, including contractile activity for gamet e transport, fertilization and early embryonic development, is mediated by physiological and anatomical changes in the oviduct during the estrous cycl e. Oviductal epithelial cell culture was utilized to investigate the effect of ovarian steroids (progesterone [P4] and estradiol 17 beta[E2]), oxytoci n (OT) and luteinizing hormone (LH) on the local production of prostaglandi n E2 (PGE2), prostaglandin F2 alpha (PGF2 alpha) and endothelin-1 (ET-1) in the cow oviduct. Epithelial cells isolated from oviducts collected during the follicular phase were cultured in M199 under standard culture condition s until monolayer formation. Then the cells were trypsinized and plated at a density of 3x10(4)/mL/well and cultured again until subconfluency, at whi ch time the cells were incubated for 4 or 24 h with M199 only (control), hi gh P4 (H-P4;1 mu g/mL), low P4 (L-P4;10 ng/mL), E2 (1 ng/mL), LH (10 ng/mL) , OT (10(-9) Evil ET-1(10(-9) M), PGE2 (10(-8) M) PGF2a (10 M) or their com bination (H-P4+E2, L-P4+E2, LH+E2, ET-1+E2, L-P4+E2+LH and H-P4+E2+LH). The production of both PC and ET-1 was increased by E2+low P4 and LH-E2+low P4 (P<0.05), while LH+E2 enhanced the production of PGF2 alpha and ET-1 (P<0. 05). Moreover, E2+ET-1 stimulated PG production (P<0.05). However, OT had n o effect on the production of any of these substances. These results sugges t that the preovulatory LH surge, together with locally re-circulated high levels of E2 from the Graafian follicle and basal P4 from regressing corpus luteum (CL), induces the maximum stimulatory effect on oviductal PGE2, PGF 2a and ET-1 production during the periovulatory period. Consequently, the e levated local ET-I concentration during periovulatory period may induce the high contractile activity of the oviduct and, at the same time, the stimul ation of PG production. Thus, ET-1 may act as a local amplifier for oviduct al PG production stimulated by LH and ovarian steroids. (C) 1999 by Elsevie r Science Inc.