Brown fat and nonshivering thermogenesis in the gray mouse lemur (Microcebus
murinus).
Génin, F., M. Nibbelink, M. Galand, M. Perret, and L. Ambid.
1,3,4«cnrs» UMR 8571, MNHN, Laboratoire d'Ecologie Générale, F«hyphen»91800
Brunoy; and 2,5«cnrs» UMR 5018, Laboratoire de Neurobiologie, Plasticité Tissulaire et
Métabolisme Énergétique, CHU Rangueil, 31403 Toulouse cédex, France
APStracts 9:0014R, 2003.
The gray mouse lemur Microcebus murinus is a rare example of a primate exhibiting
daily torpor. In captive animals, we examined the metabolic rate during arousal from
torpor and showed that this process involved nonshivering thermogenesis (NST). Under
thermoneutrality (28°C), warming-up from daily torpor (body temperature <33°C)
involved a rapid (<5 min) increase of O2 consumption that was proportional to the
depth of torpor (n = 8). The injection of a ß-adrenergic agonist (isoproterenol) known to
elicit NST induced a dose-dependent increase in metabolic rate (n = 8). Moreover,
maximum thermogenesis was increased by cold exposure. For the first time in this
species, anatomic and histological examination using an antibody against uncoupling
protein (UCP) specifically demonstrated the presence of brown fat. With the use of
Western blotting with the same antibody, we showed a likely increase in UCP expression
after cold exposure, suggesting that NST is also used to survive low ambient
temperatures in this tropical species.
Received 29 August 2002; accepted in final form 18 November 2002
APS Manuscript Number R525-2.
Article publication pending Am J Physiol Regul Integr Comp Physiol
ISSN 1080-4757 Copyright 2002 The American Physiological Society.
Published in APStracts on 29 January 2003