Glucocorticoid-induced glucose release is abolished in trout hepatocytes with elevated hsp70 content.
The metabolic potential of cells with elevated heat shock protein 70 (hsp70) content was examined by measuring unstimulated and glucocorticoid-stimulated glucose release in trout hepatocytes maintained in primary culture. Exposure of hepatocytes to either heat shock (HS;+15 degrees C) or sodium arsenite (50 microM) did not affect cell viability, but resulted in significantly higher hsp70 levels over a 24 h recovery period. Hsp70 accumulation had no significant impact on unstimulated glucose release, but completely abolished cortisol-induced glucose release in trout hepatocytes. This lack of glucocorticoid responsiveness corresponded with lower glucocorticoid receptor protein levels. Together, our results suggest that stressor-induced hsp70 accumulation, while important for maintaining cellular homeostasis, may impair metabolic adjustments to subsequent stressors in animals, especially those that are glucocorticoid-dependent.
Boone
A N
AN
Department of Biology, University of Waterloo, Waterloo, Ontario, N2L 3G1 Canada.
Ducouret
B
B
Vijayan
M M
MM
D000818:Animals; D018053:Arsenites / Q000378:metabolism; D015153:Blotting, Western / Q000379:methods; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D005947:Glucose / Q000032:analysis / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006854:Hydrocortisone / Q000494:pharmacology*; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D008099:Liver / Q000378:metabolism*; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D011965:Receptors, Glucocorticoid / Q000378:metabolism
D018053:Arsenites; D018840:HSP70 Heat-Shock Proteins; D011965:Receptors, Glucocorticoid; D007770:L-Lactate Dehydrogenase; D005947:Glucose; C015001:arsenite; D006854:Hydrocortisone