Induced Ovulation in Amphibians by Injection of Antuitrin-S

Abstract

Japanese newts, Triturus (Molge) pyrrhogaster, were given injections of Antuitrin-S, a sex-stimulating extract from the urine of pregnant women, twice daily for 5 days, with the result that eggs were laid on the sixth day. The total number of eggs laid was about 50 of which 27 were fertile and from which number 21 developed into swimming larvae. Both the males and the females were injected at the same time, 0.2 cc. twice a day, subcutaneously in the abdominal region.

The same extract was used in experiments on the Mexican axolotl, generally considered a neotenous form of Amblystoma tigrinum, with the following results.

Experiment I. 2 males and 2 females were injected during the same period, with 0.3 cc. of Antuitrin-S 3 times a day for 4 days. Several hundred eggs were laid on the fifth, sixth, and seventh days, These eggs were not fertile.

Experiment II. 2 males only were injected with 0.3 cc. three times a day, after which they deposited 15-20 spermatophores on the fourth day. 2 females were then injected (on the fourth day of the experiment) 3 times with 0.3 cc. and eggs were laid that night and on the succeeding 4 days. These eggs were mostly infertile, only a few of them going through the second cleavage stage.

Experiment III. 2 males were injected with the same amounts as in previous experiments. Twenty to 25 spermatophores were deposited on the fourth and fifth days. Two days later (on the sixth day) the females laid several hundred eggs, all of which were fertile.

From the last 3 experiments it will be seen that treatment of the male will arouse sexual activity resulting in the deposition of spermatorphores.

These spermatophores are picked up by the females which lay their eggs without treatment.