Prevention of Experimental Uterine Bleeding in Macacus Monkey by Corpus Luteum Extract (Progestin). ∗

Since uterine bleeding was shown to follow cessation of follicular treatment, the many observations on experimental menstruation in the monkey have not given adequate consideration to the role of the corpus luteum. Experiments were designed to study this question. Adult or subadult animals, all beyond the first menstruation (3700 to 5150 gm. B.W.) were injected with the follicle stimulating water soluble fraction of sheep pituitaries (Pyridine method of Fevold, Hisaw and Leonard) for 10 to 14 days. Coincident with the last 4 of these injections oestrin (Theelin) was also given in large doses (100 R.U. per diem)∗∗. The uterus at the end of the treatment was large, firm and of a deep red color. It is known that the animal will bleed within 6 days of the cessation of this treatment. Bilateral ovariectomy was also performed, which alone will be followed by uterine bleeding. On this day of ovariectomy, treatment was begun with Progestin (method of Corner and Allen), giving generally 70 gm. equivalent of fresh sow corpora daily∗∗∗. Bleeding has never occurred during the course of treatment with progestin, and has been prevented, in various animals for from 10 to 28 days after the double stimulus to bleeding afforded by bilateral ovariectomy and cessation of oestrin treatment. The preparation has one R.U. of oestrin per 19 gm. equivalent which is quite inadequate to prevent uterine bleeding.

A typical animal (My89, wt. 4.4 K.) was given 15 days of aqueous solution of anterior pituitary (dry gland equivalent of 17 gm.). During the last 4 days of this period 100 R.U. oestrin (Theelin, P. D. & Co.) was administered daily. On operation the ovaries were large (1.172 gm.) and contained numerous cystic follicles, no corpora.