Thermogenic capacity in shrews
1. Mass-independent (division of body mass to the 2/3 power) resting metabolic rates (RMR) were greater in the shrew (Sorex vagrans) than in the three rodent species studies (Peromyscus maniculatus, Reithrodontomys megalotis and Microtus montanus).
2. Norepinephrine-induced nonshivering thermogenesis (NST) was not different among the four species studied, but for the shrew, was less than predicted by body mass.
3. Specific GDP binding to brown fat mitochondria, an index of brown fat thermogenic capacity and thus nonshivering thermogenic capacity, was also depressed in the shrews.
4. Acute (2 h) cold exposure of S. vagrans or P. maniculatus had no effect on brown fat GDP binding.
5. These observations are consistent with the hypothesis that regulatory nonshivering thermogenic capacity is relatively low in shrews.
brown adipose tissue, Microtus montanus, mitochondrial GDP binding, nonshivering thermogenesis, Peromyscus mani culatus, Reithro dontomys megalotis, resting metabolic rate, cold-induced metabolic rate, Shrews, Sovex vagrans
Tomasi, Thomas E., Jock S. Hamilton, and Barbara A. Horwitz. "Thermogenic capacity in shrews." Journal of thermal biology 12, no. 2 (1987): 143-147.
Journal of Thermal Biology