[Rat ovarian function after post or prenatal injection of clomiphen]

If newborn rats are subcutaneously injected with 0,075--0,100 mg of Clomiphene Citrate within the first 5 days, it results that 73.7% of the females remain anovulatory. The percentage rises to 100 if 0,125--0,400 mg are given in several injections. The identical treatment has no influence on the testicular function. Prenatal administration to pregnant rats (total amount 0,250--2,70 mg in repeated subcutaneous injections) interrupts the pregnancy in a high percentage, but has no effect on the later gonadal function of the foetuses. Equally ineffective is the prenatal intra-amniotic injection of clomiphene (0,125--0,250 mg into each amniotic cavity). In this respect the action of Clomiphene differs from the action of testosterone and also of estradiol, as these two hormones produce the identical effect after intra-amniotic as after postnatal administration i.e. they are effective if passage through the placenta is avoided. Clomiphene, postnatally effective, loses its effectiveness when intra-amniotically injected, although the placenta is eluded. An inactivating action of the amnion fluid could be the explanation of this phenomenon.