Cold-acclimation improves cold-tolerance of diabetic rats.
1. The aim of these experiments was to study the extent to which previous cold-acclimation improves the cold-tolerance of diabetic rats. 2. Alloxan diabetic rats (fasting blood glucose higher than 200 mg/dl) were used in the experiments. 3. In Expt. 1, non-cold-acclimated control and diabetic rats were exposed to cold environment (7-9 degrees C), and the percentage of survival calculated during a 12-day experimental period. In Expt. 2, the rats were previously cold-acclimated before alloxan or saline injection (diabetic and control cold-acclimated rats) and the survival rate was also assessed during a 12-day period in the cold. 4. The percentage of survival of the non-cold-acclimated diabetic rats (Expt.1) was 19% compared with 79% of the diabetic cold-acclimated animals (Expt. 2). There were no deaths in the control groups. 5. Cold-acclimated diabetic rats maintained a near-normal thermogenic response after noradrenaline injection. This response was impaired in non-cold-acclimated diabetic rats. 6. The results of these experiments suggest that the enhanced cold-tolerance of diabetic cold-acclimated rats could be related to the increased sympathetic activity and enhanced insulin sensitivity in thermogenic tissues, such as brown fat.
D000064:Acclimatization; D000818:Animals; D001833:Body Temperature Regulation / Q000187:drug effects; D001835:Body Weight; D003080:Cold Temperature; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D013997:Time Factors
D009638:Norepinephrine