Meeting Abstract
The endocrine mechanisms regulating reproductive behavior vary across species. Comparative differences in the effects of hormones can be due to differences in life history. In certain urodele amphibians, prolactin can be used to induce and maintain sexual receptivity. Urodele reproduction typically involves the transition from a terrestrial to an aquatic environment. In contrast, African clawed frogs, Xenopus laevis, are fully aquatic anuran amphibians. Xenopus typically spend their entire lives in murky ponds and mating occurs primarily at night, thus Xenopus use vocal communication to locate potential mates. We investigated whether prolactin would induce sexual receptivity in X. laevis by measuring advertisement calling after prolactin injection. While prolactin did not induce advertisement calling, it did cause the molting of the cornified layer of the skin. Prolactin acts as an osmoregulatory hormone in many vertebrates, and our findings suggest that the role of prolactin in urodele reproductive physiology and behavior may have evolved because of a coincidental change in osmoregulatory needs that occurs when the newts must adjust to an aquatic environment for mating. In X. laevis, which do not move from terrestrial to aquatic environments in order to mate, prolactin does not induce reproductive behavior but still appears to play a role in osmoregulation. Further research is needed to determine the effects of prolactin on the skin.
