Studies on Gonadotropic Antihormones

Abstract

This work was originally begun with the idea of determining, if possible, the nature of the “inhibiting substance” which Collip et al., 1 – 5 have described and designated as “antihormones.” The controversy which has arisen involves the question as to whether the action of the “antihormone” may not in reality be due to an antibody developed against the protein, which is always found in hormone preparations derived from human or animal source. It is our belief that the gonadotropic inhibiting substance is separate and distinct from the antiprotem and both are present in the antiserums obtained from rabbits which have been persistently injected with large doses of pituitary extract or P.U.∗ hormone.

One male and 3 female adult rabbits were injected over a period of 3 weeks, receiving 5 cc. of pituitary extract (E. R. Squibb and Sons) daily, totaling 900 growth units each. The antiserums, inactivated at 56° for 1/2 hour, gave a precipitin reaction with pituitary extract. On testing the pituitary extract for gonadotropic hormone, we found that 1/6 cc. injected intravenously into a female† rabbit gave corpora lutea. With the addition of 1 cc. of the antiserum to 1/3 cc. of pituitary extract, a heavy precipitate formed. The supernatant along with the precipitate was injected intravenously into an immature female rabbit. Examination of the ovaries 48 hours later showed no stimulation. Similar results were obtained with the other 3 antiserums.

We attempted to remove the anti-bovine protein present in our pituitary antiserums by treatment with normal bovine serum. Two cc. of bovine serum (1–100) incubated 2 hours with 2 cc. of pituitary antiserum gave a heavy precipitate which was centrifuged out.