Reduced glucose availability induces torpor in Siberian hamsters.
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.
Dark
J
J
Department of Psychology, University of California, Berkeley 94720.
Miller
D R
DR
Zucker
I
I
D000818:Animals; D001682:Biological Availability; D001786:Blood Glucose / Q000032:analysis; D001831:Body Temperature / Q000187:drug effects; D006224:Cricetinae; D003847:Deoxyglucose / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005215:Fasting; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000493:pharmacokinetics*; D010084:Oxidation-Reduction; D017111:Phodopus / Q000502:physiology*; D012894:Sleep Stages / Q000502:physiology*; D013864:Thioglycolates / Q000494:pharmacology
D001786:Blood Glucose; D005227:Fatty Acids; D013864:Thioglycolates; C017487:2-mercaptoacetate; D003847:Deoxyglucose; D005947:Glucose