Studies in glucose tolerance: (1) the intravenous glucose tolerance test; (2) cortisone induced impairment of glucose tolerance in the detection of the diabetic diathesis.

Abstract

1. THE INTRAVENOUS GLUCOSE TOLERANCE TEST By L. J. P. DUNCAN REPRINTED FROM THE QUARTERLY JOURNAL OF EXPERIMENTAL PHYSIOLOGY (Vol. 41, No. 1) 1956.

2. Cortisone induced impairment of glucose tolerance in the detection of the diabetic diathesis. By L. J. P. DUNCAN.

(i) The effect of cortisone on glucose tolerance was investigated by the administration of 200 mg. of cortisone 120 minutes before an intravenous glucose tolerance test. The resultant increment index (I.I.) has been compared with the control I.I.

(ii) In 20 normal persons no change was observed following cortisone,

(iii) In 16 mildly diabetic patients the I.I. after cortisone was lower than the control I.I. by an average of 33 per cent.

(iv) In 10 patients with latent diabetes the I.I. after cortisone was lower than the control I.I. by an average of 35.5 per cent.

(v) Nineteen persons suspected of being in a prediabetic state were tested and in nine, cortisone induced a lowering of the I.I. by at least 30 per cent. of the control I.I. value. Of these patients two have subsequently become clinically diabetic. In no other persons tested was this cortisone -induced impairment of glucose tolerance observed.

(vi) It is suggested that the use of an intravenous technique for the determination of glucose tolerance is the most precise measure of that function, and that the impairment of glucose tolerance induced by preliminary administration of cortisone makes it possible to diagnose the diabetic diathesis before any defect in carbohydrate tolerance is demonstrable by other laboratory tests.