Meeting Abstract

S1.9  Monday, Jan. 4  Origins of the Neuroendocrine System in a Basal Vertebrate, the Sea Lamprey SOWER, STACIA A.*; KOSUGI, TAKAYOSHI; AQUILINA-BECK, ALLISAN; FREAMAT, MIHAEL; University of New Hampshire, Durham; University of New Hampshire Durham; University of New Hampshire, Durham; University of New Hampshire, Durham sasower@cisunix.unh.edu

The hypothalamic-pituitary (HP) system is considered to be a vertebrate innovation and seminal event that emerged prior to or during the differentiation of the ancestral agnathans and led to the neuroendocrine control of many complex functions including growth, reproduction, osmoregulation, stress and metabolism (Sower et al., 2009). In spite of the very diverse patterns of life cycles and reproductive strategies and behaviors, this endocrine system is remarkably conserved throughout the gnathostome lineages. For neuroendocrine studies, the availability of the genome has been critical for identification of ligands and receptors. We will report on some of our latest findings from the lamprey genome that includes the identification of lamprey (l) GnRH-II, two novel GnRH receptors (lGnRHR-2 and GnRHR-3, and two glycoprotein hormone receptors, (lGpHR-I, gonadal-like and lGpHR-II, thyrotropic-like) as well as functional studies on the GnRH and glycoprotein hormone receptors. From our data we propose a model in that the neuroendocrine control of reproduction and thyroid functions in an Agnathan, the sea lamprey, exhibits an overlapping, simplified organization represented by one and possibly two glycoprotein hormones putatively interacting with two glycoprotein receptors, a gonadotropin-like receptor and a thyroid stimulating hormone-like receptor. This paradigm can serve as a model for analysis of the evolutionary mechanisms leading to emergence of the highly specialized Gnathostome endocrine axes. Supported by NSF IBN-0421923, IOS-0849569, NH AES Hatch 332 and NIH 5R21RR024477-02 to SAS.