US-UK Dissertation Enhancement: Evolution of Unusual Steroids in Lamprey Species

Michigan State University, East Lansing MI

Investigators

Abstract

0336929 Li This U.S.-U.K. dissertation enhancement project involves Weiming Li of Michigan State University, doctoral student Mara Beth Bryan, and Andrew Scott of the U.K. Centre for Environment, Fisheries and Aquaculture Science. The award supports a two-month visit by the doctoral student to investigate the presence and possible functionality of unusual 15a-hydroxylated steroids in European river lamprey (Lampetra fluviatillis). This line of research enhances the dissertation effort currently focused on the structure and functionality of 15a-hyroxylated steroids in the sea lamprey (Petromyzon marinus). The goal is to determine if the 15a-hyroxylated steroids (gonadal steroids) are ancestral and universal in lampreys by investigating their role in the European river lamprey, the most derived lamprey genus. The objectives are to study the steroids in the river lamprey's gonadal tissues in vitro, steroid circulation and production in vivo, changes in steroid levels in response to GnRH administration. Research on steroids in lampreys has implications in evolution and biodiversity of endocrine functions, as lampreys are the earliest evolving extant vertebrate studied for the hypothalamus-pituitary-gonadal axis. However, most research has focused on hormones of the hypothalamus and pituitary, and has been conducted on a single species, the sea lamprey. This dissertation project extends these studies to gonadal steroids in several different species. The project takes advantage of access to unique facilities in the United Kingdom which house river lampreys. The results will further understanding of conservation and control efforts for various lamprey species, which in different parts of the world are endangered, threatened, or considered as an invasive species.