We tested whether reduced blood glucose concentrations are necessary and sufficient for initiation of torpor in Siberian hamsters. During spontaneous torpor bouts, body temperature (T_b) decreases from the euthermic value of 37 to <31°C. Among hamsters that displayed torpor during maintenance in a short-day length (10 h light/day) at an air temperature of 15°C, blood glucose concentrations decreased significantly by 28% as T_b fell from 37 to <31°C and increased during rewarming so that by the time T_b first was >36°C, glucose concentrations had returned to the value preceding torpor. Hamsters did not display torpor when maintained in a long-day length (16 h light/day) and injected with a range of insulin doses (1-50 U/kg body mass), some of which resulted in sustained, pronounced hypoglycemia. We conclude that changes in blood glucose concentrations may be a consequence rather than a cause of the torpid state and question whether induction of torpor by 2-deoxy-D-glucose is due to its general glucoprivic actions.

body temperature; thermoregulation; insulin; 2-deoxy-D-glucose

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				H. H. Bae, J. L. Stamper, E. C. Heydorn, I. Zucker, and J. Dark Role of area postrema in control of torpor in Siberian hamsters Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2000; 279(2): R591 - R598. [Abstract] [Full Text] [PDF]