RESUMEN
An experimental model was set up to show whether PGF2alpha caused luteolysis when adequate chorionic gonadotropin was administered. Four mature female rhesus monkeys were studied for two cycles each. HCG was given after ovulation until day 36. PGF2alpha was given on days 28 and 29 in one cycle, while the other served as control. In five out of the total eight cycles studied, the luteal function was maintained up to day 36. However, gradual decline of serum progesterone was noted after days 22 to 26 despite the continuous administration of hCG. Administration of PGF2alpha on days 28 and 29 did not accelerate CL regression. It was also noted that hCG in doses of 500 IU did not maintain CL function in three of four cycles when surgical stress was added.