AJP - Regulatory, Integrative and Comparative Physiology, Vol 267, Issue 2 496-R501, Copyright © 1994 by American Physiological Society
Reduced glucose availability induces torpor in Siberian hamsters
J. Dark, D. R. Miller and I. Zucker
Department of Psychology, University of California, Berkeley 94720.
Siberian hamsters kept in long photoperiods (16 h light/day) at 10 degrees
C do not display torpor when provided with food ad libitum but do reduce
their body temperatures (Tb) from 37 degrees C to as low as 15 degrees C
for several hours each day in response to food restriction. Female hamsters
maintained in a long photoperiod and fed ad libitum were injected with
2-deoxy-D-glucose (2-DG), a glucose analogue that reduces cellular glucose
oxidation, or mercaptoacetate (MA), a drug that disrupts fatty acid
oxidation. Dosages of 2-DG in excess of 1,500 mg/kg body mass reliably
induced torpor with latencies of approximately 50 min from time of
injection to a decrease in Tb below 30 degrees C; 79% of females displayed
torpor at a dosage of 2,500 mg/kg. MA was uniformly ineffective in inducing
torpor and did not increase incidence of torpor when combined with 2-DG
treatment or food restriction. Decreased availability of glucose may be the
major metabolic signal for inducing torpor in Siberian hamsters;
availability of fatty acids appears to play little if any role in
regulating this behavior.
