Long chain polyunsaturated fatty acids and bovine luteal cell function.

Experiments were conducted to determine the effects of exogenous polyunsaturated fatty acids (PUFA) on the production of progesterone and prostanoids by dispersed bovine luteal cells and to characterize endogenous luteal fatty acids throughout the estrous cycle. The addition of eicosapentaenoic acid (20:5, n3) resulted in a dose-dependent reduction of progesterone production and an increase in production of prostaglandin (PG) F2 alpha (PGF2 alpha) (p < 0.05). Nordihydroguaiaretic acid abolished the inhibitory effects of 20:5, n3 on progesterone production, while indomethacin did not alter these effects. The addition of 10 micrograms docosahexaenoic acid (22:6, n3) resulted in a suppression of progesterone synthesis (p < 0.05) and reduced PGF2 alpha synthesis. The addition of 0.1, 1, and 10 micrograms docosatetraenoic acid (22:4, n6) inhibited basal progesterone production, whereas only the highest dose decreased LH-stimulated synthesis of progesterone. The addition of 22:4, n6 resulted in increased PGF2 alpha synthesis (p < 0.05) and in lowered synthesis of prostacyclin (p < 0.05). Variations in luteal fatty acids were confirmed by an experiment in which endogenous fatty acids were characterized throughout the estrous cycle. The percentages and ratios of PUFA were altered throughout the estrous cycle. In summary, PUFA have potent inhibitory effects on the production of progesterone and PGI2 in vitro and may play a role in bovine luteal cell function by mechanisms yet to be determined.