[Effect of uterine prostaglandin F2 alpha on the level of ovarian steroids in rats (author's transl)].

Effects of intra-uterine or tail vein administration of prostaglandin (PG) F2 alpha on hormone levels in ovaries were studied. Adult Wistar rats weighing 150-180 g were used. PGF2 alpha was injected into the uterine lumen (100 ng/rat) and tail vein (200 ng/0.1 ml) of estrus rats, respectively, and intra-uterine administration of PGF2 alpha was given to hypophysectomized rats. Variation in the levels of ovarian steroids (estradiol, progesterone, 20 alpha-hydroxypregn-4-en-3-one (20 alpha-OH-P) were studied. The amount of PGF2 alpha injected into rats was minute compared with that of the usual PGF2 alpha injection (microgram/0.1 ml). Before start of the experiments, the levels of ovarian steroids of adult rats in all stages of estrous were measured. Each of the three steroids showed a maximum level at the time of proestrus. When PGF2 alpha was administered into the uterine lumen and tail vein of rats, the level of estradiol increased gradually, while that of progesterone and 20 alpha-OH-P decreased sharply at 10 min (p <0.05) after administration. On the other hand, when PGF2 alpha was given into the uterine lumen of hypophysectomized rats, the reverse pattern was seen, that is, estradiol decreased, whereas progesterone and 20 alpha-OH-P gradually increased. Thus, the intrauterine administration of PGF2 alpha does have an effect on levels of ovarian steroids.