Abstract
Effects of intra-uterine or tail vein administration of prostaglandin (PG) F2α on hormone levels in ovaries were studied. Adult Wistar rats weighing 150-180 g were used. PGF2α 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 PGF2α was given to hypophysectomized rats. Variation in the levels of ovarian steroids (estradiol, progesterone, 20a-hydroxypregn-4-en-3-one (20α-OH-P)) were studied. The amount of PGF2α injected into rats was minute compared with that of the usual PGF2α injection (μg/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 PGF2α was administered into the uterine lumen and tail vein of rats, the level of estradiol increased gradually, while that of progesterone and 20α-OH-P decreased sharply at 10 min (p<0.05) after administration. On the other hand, when PGF2α was given into the uterine lumen of hypophysectomized rats, the reverse pattern was seen, that is, estradiol decreased, whereas progesterone and 20α-OH-P gradually increased. Thus, the intrauterine administration of PGF2α does have an effect on levels of ovarian steroids.
