Non-specificity of Anuran Hypophyses in Induction of Ovulation in Toads. ∗

Abstract

Experiments were conducted to determine the specificity of the anuran hypophysis in producing ovulation in the toad (Bufo americanus). Houssay, Giusti, and Lascano-Gonzalez 1 , 2 advanced the theory of “zoological specificity ”when they were unable to secure ovulation in toads (Bufo arenarium) using hypophysis implants from several classes of animals, including frogs. They were, however, able to start ovulation in frogs, using hypophysis implants from toads. Adams 3 repeated these experiments, using European species and also made additional experiments using mammalian extracts of the anterior lobe and concluded that only the hormone produced by the toad could stimulate toad ovaries to release their eggs. Recently Bardeen 4 has reported the failure to produce ovulation in Bufo americanus after implanting 2 frog hypophyses daily for 15 days.

Adams 5 , 6 , 7 and Burns and Buyse 8 , 9 have shown that in urodeles the use of mammalian extracts of hypophysis or the use of heteroplastic implants from various groups of animals causes ovulation in sexually mature females. From the above results it is seen that the toads are the only group of amphibians in which there is a supposed specificity of hypophysis hormone.

In the authors' experiment 2 females of Bufo americanus were taken from the general stock on October 14th to be used as recipients of implants of hypophyses from frogs. The implants were placed in the dorsal lymph sac just posterior to the head. Each female received 4 hypophyses daily. The first day each was given 3 implants from Rana sphenocephala and 1 from Rana pipiens and the following day the donors were all of the latter species. The first female ovulated completely on the third day after having received, altogether, 8 frog hypophyses.