The evolution of endocrine function; discovering the hormonal control of osmoregulation in basal vertebrates

The neuroendocrine system is the major mechanism through which changes in the environment are detected and transduced into a coordinated physiological response.  Our current understanding of the hormonal control of osmoregulation in aquatic vertebrates comes almost entirely from work on advanced teleosts, in which prolactin (PRL) promotes osmoregulation in freshwater (FW) and growth hormone (GH) promotes osmoregulation in seawater (SW). Lamprey are basal vertebrates and sturgeon are basal bony fishes that share the same osmoregulatory strategy as teleosts and present a unique opportunity to examine the early evolution of the pituitary control of osmoregulation, which to date has been largely unexamined.  


Our specific aims in this project are to 1) Determine the response of GH and GH receptor to salinity change in lamprey, 2) Determine the osmoregulatory actions of GH in lamprey, and 3) Determine the osmoregulatory roles of GH and PRL in sturgeon. We hypothesize that GH is a SW-acclimating hormone in sea lamprey and that distinct functions of FW acclimation by PRL, and SW-acclimation by GH, will be found in Atlantic sturgeon. By determining for the first time the osmoregulatory function of prolactin and growth hormone in the more basal extant vertebrates, this project will have profound implications for our understanding of endocrinology among all vertebrates including humans. We expect our results to provide evidence of the earliest function of prolactin and growth hormone that can contribute to the revision of physiology and endocrinology textbooks. The results will also have application to the aquaculture and conservation of endangered sturgeon populations and the management of invasive lamprey.

Principle Investigators:

Dr. Stephen McCormick, USGS Conte Anadromous Fish Research Center, Turners Falls, MA, USA and Department of Biology, University of Massachusetts, Amherst, MA, USA.


Postdoctoral Fellow:

Dr. Diogo Ferreira-Martins, Department of Biology University of Massachusetts Amherst, Amherst, MA, USA.


Graduate Student: 

Ciaran Shaughnessy, Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts Amherst, Amherst, MA, USA. 



Professor Mark A. Sheridan, Texas Tech University.

Dr. Ningping Gong, Texas Tech University. 




Supported by the National Science Foundation

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