Meeting Abstract

P3.74  Tuesday, Jan. 6  Response of leptin I and II to cold acclimation in carp. LONDRAVILLE, R.L.*; HEMLEPP, L; COPELAND, C; SCARBOROUGH, J; University of Akron; University of Akron; University of Akron; University of Akron londraville@uakron.edu

Leptin is a small (16 kDa) peptide hormone that influences fat deposition, metabolic rate, satiety, reproduction, angiogenesis, bone density and immune function in mammals. Its study in basal vertebrates has been hampered by difficulty cloning the cDNA; however recent labs have had success for fish, including Fugu (Kurokawa and Suzuki, Peptides 26:745, 2005) and Cyprinus carpio (Huising et al., Endocrin. 147: 5786, 2006). Carp are the only vertebrates reported to date that express multiple isoforms of leptin. As temperate-zone fishes typically accumulate body lipid as they acclimate to temperatures, we acclimated carp to 5C and 25C for 8 weeks to measure the response of each leptin isoform to leptin exposure. Semiquantitative PCR indicates that cold exposure significantly increases mRNA expression of both leptin isoforms. Currently we are confirming these results with quantitative (real-time) PCR. These data indicate that the leptin signal in ectotherms remains coupled to adipose stores (both increase with cold exposure) as opposed to endotherms, where adipose stores increase while leptin decreases.