Endocrinology of a Viviparous Amphibian

University Of Notre Dame, Notre Dame IN

Investigators

Abstract

The ability to give birth to live young occurs in all classes of vertebrates except cyclostomes and birds. In a unique order of tropical amphibians, the caecilian amphibians, the majority of species give birth to live young but the physiological mechanisms which control this process are unknown. It is proposed that fetal caecilian gills function as endocrine organs and produce hormones similar to those produced by mammalian placentas. Such structures have not been described in non-mammals. The goal of this project is to determine whether fetal caecilian tissues produce steroid hormones. The methods to be used include identification of steroid metabolites produced by tissues in vitro and localization of enzymes known to function in steroid synthesis. Maternal steroid hormone levels will be determined. These studies will provide the first information on steroid endocrinology and the control of live- bearing for this order of amphibians. They will thus contribute substantially to understanding of reproductive biology and conservation of these unique animals and also to hormonal control of pregnancy in other vertebrates.