Adaptive changes in insulin and glucagon secretion during cold acclimation in the rat.
Arginine-stimulated insulin and glucagon outputs from isolated perfused pancreata of warm-acclimated and 2-, 4-, and 6-wk cold-acclimated rats (4 degrees C) were determined to assess whether observed changes in these parameters were a result of cold exposure per se or a part of the adaptive process of cold acclimation. Progressive and sequential changes were seen in both insulin and glucagon outputs. At 2 wk cold acclimation, glucagon rose and insulin output tended to fall, at 4 wk, glucagon output remained elevated and insulin output was further reduced, and at 6 wk, glucagon output had returned to control levels, whereas insulin output was substantially further reduced. These changes resulted in reduction of the insulin-to-glucagon molar ratio of the total arginine-induced output from 7.27 +/- 1.76 (SE) in the warm acclimate to 2.31 +/- 0.79 (SE) at 2 wk, 1.42 +/- 0.29 (SE) at 4 wk, and 1.26 +/- 0.21 (SE) at 6 wk cold acclimation. The data do not provide in vitro support for the hypothesis that changes in pancreatic hormone secretion in vivo are a consequence of cold exposure and not cold acclimation.
D000064:Acclimatization; D002001:Adipose Tissue, Brown / Q000033:anatomy & histology; D000818:Animals; D001120:Arginine / Q000494:pharmacology; D001835:Body Weight; D003080:Cold Temperature; D005934:Glucagon / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D008297:Male; D010179:Pancreas / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D007328:Insulin; D005934:Glucagon; D001120:Arginine