Meeting Abstract

P3.122  Jan. 6  Comparison of Standard Metabolic Rate and Uncoupling Protein-2 in the Common Snapping Turtle Chelydra serpentina KEMP, HR*; STEYERMARK, AC; Univ. of St. Thomas; Univ. of St. Thomas hrkemp@stthomas.edu

Following the identification of uncoupling protein-2 (UCP2) as a mitochondrial carrier protein homologous to the original uncoupling protein UCP1 (thermogenin) and subsequent discovery that UCP2 was expressed ubiquitously, many studies have investigated the family of uncoupling proteins. In spite of all this interest, the physiological role of UCP2 is still unknown. Studies have claimed that upregulation of UCP2 results in decreased mitochondrial potential. Some have postulated from this that UCP2 may play a role in non-shivering thermogenesis similar to UCP1. If that is case, then one would expect to find a relationship between UCP2 and standard metabolic rate (SMR), a physiological quality linked closely to mitochondrial membrane potential. We investigated the relationship between relative UCP2 content and SMR in the common snapping turtle, Chelydra serpentina. Standard metabolic rate was determined by carbon dioxide consumption measured using an open-flow, push-through respirometry system. Following SMR determination, each turtle was sacrificed, its liver harvested, and liver mitochondrial protein was probed for UCP2 content using western blotting. Blots were analyzed to determine relative UCP2 content. Initial results indicate no significant relationship between relative UCP2 content and mass adjusted SMR. Pending further data collection and analysis, our results lend support to those that reject the idea that the function of UCP2 was thermogenic.