Corticosterone-induced insulin resistance is not associated with alterations of insulin receptor number and kinase activity in chicken kidney.

Chicken renal insulin receptors have been recently characterized; their number and kinase activities vary in response to altered nutritional status. In the present study, the effect of chronic corticosterone treatment was examined in 5-week-old chickens. The development of an insulin resistance following corticosterone was suggested after 1 and 2 weeks of treatment by a significant increases in plasma insulin levels (1.63 +/- 0.13 vs 0.56 +/- 0.14 ng insulin/ml in controls) and in renal cytosolic phosphoenolpyruvate carboxykinase activity (17.2 +/- 0.8 vs 13.7 +/- 0.7 nm/mn/mg tissue in controls). No significant changes were present at the level of insulin receptor number and kinase activity. Therefore, in kidney and, as previously observed, in muscles, corticosterone can induce insulin resistance at postreceptor steps in the cascade of events leading to insulin action.