AJP - Endocrinology and Metabolism, Vol 250, Issue 6 669-E676, Copyright © 1986 by American Physiological Society
Adaptive changes in insulin and glucagon secretion during cold acclimation in the rat
C. I. Edwards and R. J. Howland
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.
