Erythrocyte insulin receptors and insulin sensitivity in adrenocortical insufficiency. Report of a case of diabetes mellitus type I with superimposed Addison's disease.

Studies on erythrocyte insulin receptors were performed in a boy with type I diabetes mellitus and superimposed adrenocortical insufficiency before and during treatment with hydrocortisone and 9-alpha-fluorohydrocortisone. The development of the adrenal insufficiency was associated with a progressively increased sensitivity to insulin which reverted after therapy. The maximum specific insulin binding of the erythrocytes was low during threatening addisonian crisis (6.9%) but normalized during hydrocortisone treatment (12.0%). These findings suggest that the increased insulin sensitivity characteristic for adrenocortical insufficiency is not an effect of an increased insulin receptor concentration and that hypocortisolaemia is associated with a down-regulation of the insulin receptors.