Abstract
One of us 1 pointed out the fact that in rodents the gonadotropic effect diminishes if prolan from human pregnancy urine is applied in a protracted manner. Since that time the phenomenon has been repeatedly studied. Collip, Selye, et al., 2 explained this as being due to the effect of antihormones, and succeeded in proving in the test-tube experiment the antisubstances against the hormones.
Proof of the presence of an antigonadotropic factor can be furnished only by the impairment of the gonadotropic reaction in rodents. As shown by our experiments 3 proof of the antigonadotropic factor by serological methods is not obtainable, pure prolan not forming any precipitins or complement-fixing antibodies. The sera of experimental animals which had been “immunized” with pure prolan over a period of more than 2 months do not show any serological reaction; they evince, however, a highly antigonadotropic effect.
The titration of our antigonadotropic sera was performed exclusively by impairing the production of the anterior pituitary reactions (HVR) in rodents. 0.5 cc. of an antigonadotropic serum or the corresponding amount of an antigonadotropic dry powder solution (see below) was mixed with prolan (the latter in increasing amounts), filled up to a total volume of 4 cc, placed in the incubator for 2 hours and finally injected into the experimental animals, infantile female rats 3-4 weeks old, weighing 25 to 30 gm. They were injected 4 times (if there were more than 4 cc. of the injection fluid, 6 times) at equal intervals (12 hours), spread over 36 hours. Sixty hours after the first injection we began with the vaginal smears, at intervals of 12 hours. One hundred and twenty hours after the first injection the animals were killed and ovaries and uteri examined.
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