Plasticity of non-shivering thermogenesis and brown adipose tissue in high-altitude deer mice

ABSTRACT High altitude environments challenge small mammals with persistent low ambient temperatures that require high rates of aerobic heat production in face O2 availability. An important component thermogenic capacity rodents is non-shivering thermogenesis (NST) mediated by uncoupled mitochondrial respiration brown adipose tissue (BAT). NST plastic, and for increases cold acclimation. However, lowland native rodents, hypoxia inhibits BAT. We hypothesize highland deer mice (Peromyscus maniculatus) overcome the hypoxic inhibition through changes BAT function. tested this hypothesis using lab born raised mice, a congeneric leucopus), acclimated to either warm normoxia (25°C, 760 mmHg) or (5°C, 430 mmHg). determined effects acclimation ancestry on whole-animal NST, mass interscapular (iBAT), uncoupling protein (UCP)-1 expression. To identify function, we conducted high-resolution respirometry isolated iBAT mitochondria substrates inhibitors targeted UCP-1. found increased but only mice. There was no effect any group, showed UCP-1 expression UCP-1-stimulated response these stressors. Our results suggest have evolved increase chronic hypoxia, driven part