Figure 5.

Effect of the Ca²⁺ ionophore, A23187, on basal and LH-stimulated progesterone synthesis/secretion (ng/ml) in cultured steroidogenic cells collected from Day 4 (panel A) and Day 10 (panel B) bovine CL. Progesterone accumulated in culture media was determined after 4 h of incubation in the following treatments: media alone (Media), LH (100 ng/ml), LH and PGF₂α (1000 ng/ml), or LH and A23187 (0.1, 1, 10, and 100 μmol). As explained in Materials and Methods, these treatments also contained 0.1% of the solvent used for PGF₂α and A23187, DMSO. Data are presented as the mean ± SEM of four Day 4 and 10 Day 10 individual replicates (n = 4 and 10 cows respectively). Statistical comparisons were made across treatments, and means with different letters, differ within each panel (P < 0.05).