Insulin Secretion in Addison's Disease: Effect of Hydrocortisone Treatment*

Summary The effect of hydrocortisone treatment on insulin secretion after O.G.T.T., I.V.T.T. and I.V.G.T.T. in 9 patients with Addison's disease has been studied. Tbe results showed no significant differences in fasting glycemia nor in I.R.I. levels in patients be fore and after hydrocortisone treatment. After hydrocortisone slightly higher glycemic levels after O.G.T.T. were obtained but still remaining within the adopted criteria of normality for this test. However, the insulinemic res ponse after oral glucose load was significantly enhanced (p < 0.05) at 60 and 90 minutes. Also the insulinernie res ponse induced by l.V. tolbutamide was significantly higher after hydrocortisone particularly in the very early insulin release phase (minute 1). However, hydrocortisone while slightly improving glucose peripherical uptake after I. V. glucose, did not significantly modify the insulin release pat tern. Tbe results would favour an indirect rather than a direct action of hydrocortisone on glucose induced insulin release, perhaps by amplifying the effects of the entere insular axis.