Meeting Abstract

S6-2.1  Saturday, Jan. 5  GnRH II A Multipurpose Peptide RISSMAN, Emilie F.; University of Virginia rissman@virginia.edu

We have pioneered the use of the musk shrew (Suncus murinus) for studies of reproductive behavior. One of our novel findings is that this primitive placental mammal has at least two forms of gonadotropin releasing hormone (GnRH) in brain. GnRH I is produced by forebrain neurons widely distributed from the OVLT to the POA. The other population of GnRH cells resides in the midbrain under the midbrain central gray. These neurons produce evolutionarily conserved GnRH II which is found from fish to primates, yet is not present in rodent brains. These two GnRH peptides are produced by separate genes in separate cells, have different receptors, and have largely independent projections. We have discovered two related physiological functions for GnRH II in females. When energy resources are low and females have ceased mating behavior central infusions of the peptide can reinstate sexual receptivity. In addition these infusions have an acute negative affect on food intake. We hypothesize that GnRH II acts as a metabolic sensor that permits reproduction when energy levels are high and when energy levels are low it facilitates feeding. This work was supported by NIH R01 MH068729.