Serum Immunoreactive Insulin Levels During Glucose Tolerance and Intensive Islet Stimulation: Effect of Prednisone

The effects of a potent glucocorticoid (prednisone) on hlood sugar and serum immunoreactive insulin (IRI) levels during glucose tolerance and intensive islet stimulation were studied in forty-two subjects whose glucose tolerance ranged from well-within-normal limits to frankly diabetic. The ability to maintain “normal” glucose tolerance under this added stress was not directly related to capacity for increasing serum IRI levels. “Diabetic” subjects were not more susceptible to degeneration of glucose tolerance after prednisone even though serum IRI levels increased little 01 even decreased in several subjects. The data make it difficult to directly relate the magnitude of serum IRI levels at the times measured to degree of glucose intolerance and suggest that other factors (possibly insulin resistance), as yet unknown, are operative.