Failure of Hebin to Cause Ovulation in Toads. ∗

Abstract

Hebin, the maturity hormone of pregnancy urine, has been shown by Mazer and Goldstein, 1 and Friedman 2 to produce ovulation in rats, mice, and rabbits. The authors wished to determine if hebin also acts as an inductor of ovulation in toads.

Preparation and Standardization of Hebin. The Wallen-Lawrence and Van Dyke 3 method of preparation of hebin was modified by concentrating the urine under reduced pressure at a temperature below 35°C. and separating the precipitates by filtering instead of centrifuging. In standardization, the equivalent of 0.3 cc. original urine caused the opening of the vagina in each of 3 immature 30-day old female rats; 2 of which showed oestrus cycles and ripe ovarian follicles, but only one of these 2 had an enlarged uterus. This amount was taken as a rat unit. Larger amounts of the preparation showed activity in every case.

Injection of Hebin into toads. Three sexually mature Bufo americanus females were placed with males and the former given hebin injections into the dorsal lymph sac. Daily dosages of 1, 2, and 3 rat units, respectively, were used for a period of 5 days. No ovulation occurred during this time. During the next 5 days, injections of 0.5, 1.0, and 1.5 rat units, respectively, were made every 6 hours; making a total of 15, 30, and 45 rat units used. No ovulation occurred during the next 4, 7, and 7 days respectively. The failure to obtain ovulation might be due to one of more possibilities (1) use of immature females, (2) an over-dosage causing degeneration of the ovary, (3) too small of a dosage, and (4) that hebin does not contain the active maturity principle of the anterior lobe of the hypophysis of toads.