Species-Specificity in Production of Anti-Gonadotropic Substances. ∗

Abstract

The work of Collip and his collaborators 1 has shown that the prolonged daily administration of gonadotropic extracts to rats leads to the production of substances which can inhibit the action of such hormones. The present study was conducted to determine if an “anti-hormone” developing from the injection of an extract made from the pituitary glands of one species is effective against an extract prepared from the hypophysis of another species.

A series of 39 female rats, age 21 to 23 days at the beginning of the experiment, was injected daily with a weak dose of a gonadotropic extract prepared from human pituitary glands in the manner described previously. 2 In 5 days the ovaries had increased 50% in weight and showed developing graafian follicles and corpora lutea. The ovaries of the rats sacrificed in 30 days gave an 86% increase in weight, but in 60 days they were equal to those of the controls, and in 90 and 119 days they weighed slightly less than those of controls of the same age.

The blood serum of the rats sacrificed in 90 and 119 days was examined for the presence of “anti-hormones” according to the method used by Collip and Anderson 3 in testing for an anti-thyro-tropic hormone.

A mixture of equal amounts of a human pituitary gland extract and serum from the injected rats failed to produce any increase in ovarian weight and no histologic changes when given twice daily for 4 days to 4 immature rats. However, the same extract mixed with serum from normal animals produced an average of 618% increase in weight when given in the same manner to 3 immature rats. It was apparent that the injected rats had developed the power of inhibiting gonadotropic extracts prepared from human pituitary gland material.

The serum from the injected rats also had “anti-hormone” properties against gonadotropic extracts made from the blood of pregnant women. A mixture of serum from the treated rats and a human pregnancy blood extract failed to induce any histologic change and no increase in weight in the ovaries of 4 immature rats injected as before.