Blumberg, M. S., & Sokoloff, G. Dynamics of brown fat thermogenesis in week-old rats: Evidence of relative stability during moderate cold exposure. Physiological Zoology, 70: 324-330, 1997.

Neonates of many mammalian species, including humans, depend primarily upon thermogenesis by brown adipose tissue (BAT) as a defense against cold challenge. Although the steady-state thermogenic responses of BAT to various air temperatures are well known, the dynamic responses have received relatively little attention. In this paper, we examine the relative stability of BAT thermogenesis during brief perturbations of air temperature (Ta). Specifically, week-old rats were allowed to settle at one of two levels of cold exposure. These two levels were defined on the basis of previous work as being moderate (Ta = 30.5°C) or extreme (Ta = 23°C). After pups had settled at these temperatures, they were exposed to positive or negative air temperature perturbations of approximately 3.7°C. Pups experiencing perturbations from the moderate Ta, but not the extreme Ta, exhibited organized thermogenic responses that allowed them to return quickly to their pre-perturbation conditions. These data suggest that BAT thermogenesis is more stably controlled than has previously been suspected.