The Guanosine Monophosphate Reductase Gene Is Conserved in Rats and Its Expression Increases Rapidly in Brown Adipose Tissue during Cold Exposure

摘要: Non-shivering thermogenesis is required for survival of rodents during cold stress. Uncoupling protein-1 acts in brown adipose tissue (BAT) to transport protons, thus dissipating the proton gradient across inner mitochondrial membrane. This permits respiration uncoupled from ATP synthesis. UCP-1 function inhibited by binding purine nucleotides, with GTP/GDP being more potent than ATP/ADP. We used a cDNA subtraction analysis identify cDNAs rapidly induced exposure. One these encodes rat guanosine monophosphate reductase (GMP-r). was surprising that previous data had suggested this enzyme absent rodents. Rat GMP-r 96% identical human GMP-r, and its mRNA increased 30-fold BAT within 6 h The gene also expressed (but not cold-responsive) muscle kidney, but white fat. speculate physiological marked increase stress may be deplete adipocyte guanine converting them IMP, permitting enhanced function. previously unrecognized regulatory aspect thermogenesis, an essential response cold.