PGF(2 alpha) and membrane modifiers influence progesterone production by porcine luteal cells

Large and small luteal cells were isolated from corpora lutea (CL) from prepubertal pigs on day 10 or 15 after injection of PMS/hCG. After overnight incubation in serum-free media, addition of porcine Low Density Lipoprotein (LDL) stimulated progesterone (P4) production at both 2 and 24 h of incubation in all cells from both ages of GL. Porcine LH +/- PGF(2 alpha) (0 - 100 ng/ml did not influence large cell P4 production, but LH stimulated small cells from day 10 CL at 24 h. A second experiment co-incubated cells from day 10 CL with PGF(2 alpha) (1, 100 ng/ml) and either a methyl donor (SAM, 200 mu M or one of the two inhibitors of methylation (3-DZA, 10 mu M or SAH, 1 mM). Again, large cells were unaffected. PGF(2 alpha) (1 ng/ml) alone stimulated P4 production by small cells at 2 h (P < 0.02) but not at 24 h. Co-incubation of SAM with 1 ng/ml PGR(2 alpha) inhibited small cell P4 production at both 2 h (P < 0.05) and 24 h (P < 0.018), and 3-DZA + PGF(2 alpha) tended (P = 0.065) to stimulate P4 production. Progesterone production by luteal cells from induced CL of prepubertal gilts does not appear highly susceptible to PGF(2 alpha), Disruption of P4 production by PGF(2 alpha) may be partially mediated by membrane phospholipid alterations.