PGF(2-ALPHA) AND MEMBRANE MODIFIERS INFLUENCE PROGESTERONE PRODUCTIONBY PORCINE LUTEAL CELLS

Large and small luteal cells were isolated from corpora lutea (CL) fro m prepubertal pigs on day 10 or 15 after injection of PMS/hCG. After o vernight incubation in serum-free media, addition of porcine Low Densi ty 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 produc tion, but LH stimulated small cells from day 10 CL at 24 h. A second e xperiment 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 inhi bitors of methylation (3-DZA, 10 mu M or SAH, 1 mM). Again, large cell s were unaffected. PGF(2 alpha) (1 ng/ml) alone stimulated P4 producti on 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 bo th 2 h (P < 0.05) and 24 h (P < 0.018), and 3-DZA + PGF(2 alpha) tende d (P = 0.065) to stimulate P4 production. Progesterone production by l uteal cells from induced CL of prepubertal gilts does not appear highl y susceptible to PGF(2 alpha), Disruption of P4 production by PGF(2 al pha) may be partially mediated by membrane phospholipid alterations.