Progesterone and adenosine 3',5'-monophosphate formation by isolated human corpora lutea of different ages: influences of human chorionic gonadotropin and prostaglandins.

From each of 24 women undergoing minilaparotomy at various stages of the luteal phase of the cycle, the corpus luteum (CL) was excised in toto, decapsulated, cut into pieces, and incubated for short time periods (5--120 min). Incubations were carried out in the absence and presence of hCG, prostaglandin F2 alpha (PGF2 alpha) and PGE2, both alone and in combination. Dating of the CL was done meticulously using several parameters. After incubation, the tissue levels of cAMP and the media concentrations of progesterone (P) were determined. The basal P production in vitro was highest in CL of the midluteal phase. hCG stimulated cAMP formation in CL of all ages, with the highest levels of cAMP being produced in CL of the midluteal phase. PGE2 was found to increase cAMP formation and potentiate the hCG effect in young CL, but not in CL of the midluteal phase. PGF2 alpha, alone or in combination with hCG, had no effect on cAMP or P formation in either young or old CL, while in CL of the midluteal phase, PGF2 alpha significantly counteracted the stimulatory effect of hCG on both cAMP and P formation. These in vitro data show that PGF2 alpha is capable of inducing functional luteolysis in humans.