The objective of the present study was to investigate the influence of prostaglandin F(2alpha) (PGF (2alpha)) and nitric oxide (NO) on production of steroids and PGs by culturing bovine luteal cells obtained from ovaries on days 8-12 of the estrous cycle with a nitric oxide (NO) donor (Spermine NONOate), and a NO synthase inhibitor (N(G)-nitro-L-arginine methyl ester dihydrochloride: L-NAME). When the cells were exposed for 24 h to PGF(2alpha) (10(-7)-10(-5) M), production of progesterone (P(4)) increased significantly at all doses used (P<0.05). Moreover, PGF(2alpha) stimulated PGF(2alpha) production (P<0.01), depressed testosterone (T) production (P<0.05), but did not affect synthesis of prostaglandin E(2) (PGE(2)). Spermine NONOate decreased P(4) production to 66%, 47% and 34% of the control concentration after treatment with 10(-5) M, 10(-4) M and 10(-3) M, respectively, but did not affect T production, and increased PGF(2alpha) synthesis (P<0.05) and PGE(2) (P<0.01) at all doses used. L-NAME increased production of P(4) (P<0.01) but did not affect (P>0.05) secretion of T, PGF(2alpha) and PGE(2). Estradiol-17beta (E(2)) was detectable on the level of sensitivity of assay and was not significantly altered by any treatments. The overall results suggest that PGF(2alpha) and NO produced locally in bovine CL play roles in the regulation of the secretory function of the bovine CL as auto/paracrine factors.