Cold-acclimation-recruited nonshivering thermogenesis: the syrian
hamster is not an exception.
Dicker, Andrea, Barbara Cannon, and Jan Nedergaard.
The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm
University, S-106 91 Stockholm, Sweden
APStracts 2:0096R, 1995.
Biochemical evidence from in-vitro studies of brown adipose tissue in
Syrian hamsters indicates a significant degree of recruitment of the
tissue as an effect of cold acclimation. However, earlier in-vivo
studies indicate a lack of recruitment of nonshivering thermogenesis
in the intact animal as a result of cold acclimation. Due to this
apparent discrepancy, the occurrence of cold-acclimation-recruited
nonshivering thermogenesis in hamsters was investigated. Hamsters
were cold-acclimated to 6 C or remained at 24 C (controls) and their
thermogenic response was investigated in an open-circuit system at 24
C. Cold acclimation resulted in a small increase in resting metabolic
rate and in a major increase in the thermogenic response to
norepinephrine (61% increase over resting metabolic rate in controls
and 156% in cold-acclimated). The absolute 3-specific adrenergic
agonist CGP-12177 also induced a high rate of nonshivering
thermogenesis which was similarly recruited. It was concluded that
concerning the relative effect of recruitment on the capacity for
nonshivering thermogenesis, the intact hamsters responded as would be
predicted from in-vitro experiments. Thus, the hamster does not seem
to constitute an exception to the general patterns described for
other rodents concerning recruitment of nonshivering thermogenesis
due to cold acclimation.
Received 1 September 1994; accepted in final form 30 March 1995.
APS Manuscript Number R490-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 10 April 1995.