Difference Between Human Anterior Pituitary Extract and Prolan. ∗

Abstract

Numerous investigations in the last few years have indicated that the effect of administering anterior hypophyseal substances is different from that with the gonadotropic substances found in pregnancy urine. The tests are many: differential morphological changes in mice ovaries (Engle); limitation of the size of the immature rat ovary irrespective of dosage of prolan (Evans); negative response of prolan in birds (Riddle, Schockaert, Reiss); differential effect on hypophysectomized animals (Reichert, Kraul, Smith and Leonard, White and Leonard, Collip and Selye, Wade); and the relative ovulating doses in rabbits (Leonard). In all cases heretofore, the action of prolan was compared with that of the hypophysis of species other than human, namely, the cow and sheep. Recently, it was shown that the human hypophysis was unlike prolan when tested by the ovulation test method (Leonard 1 ) in which the minimal ovulating dose in rabbits in terms of rat units equalled 1/4 R.U., whereas with prolan it equalled 2 R.U. In this paper it will be reported that the human hypophysis is unlike prolan when tested by other methods.

There is a limit of response to increasing doses of prolan in ovarian enlargement in immature rats which is about 60 mg. (Evans). Twenty immature female rats were injected with doses from 1 mg. to 10 mg. equivalent of dried human anterior pituitary for 5 days. In all cases, the vaginas opened with marked oestrus effects and on the largest doses, the ovaries weighed up to 187 mg. Contrasting to this, 100 to 400 R.U. of prolan produced ovaries weighing only 45 mg. According to this test method, the action of the human hypophysis resembles the hypophyseal action of other species and is different from prolan.