[Hormone and metabolic profile in diabetic hyperosomolar coma. Plasma insulin response to intravenous tolbutamide...

Fifteen patients with non-ketotic hyperosmolar diabetic coma were investigated and compared with ketoacidotic patients. Basal plasma insulin levels were low in all patients (14.8 +/- 1.0 micronU/ml in hyperosmolar coma, 11.0 +/- 1.3 in keto-acidosis), but insulin level increased after intravenous tolbutamide (between 30 and 105 micronU/ml) in eight hyperosmolar comas. Insulin showed no increase in seven hyperosmolar comas and in none of the ketoacidotic patients. In hyperosmolar coma plasma free fatty acids (1710 +/- 197 micronEq/1), triglycerides (3,4 +/- 0,4 g/1) and cortisol levels (49,7 +/- 9,0 microgram/100 ml) were increased, must as in keto-acidosis. Growth hormone (1,7 +/- 0,1 ng/ml) was normal, unlike the case in keto-acidosis. Plasma lactate concentrations were elevated and account for the frequent mild acidosis found in hyperosmolar coma. In spite of the low peripheral "insulin/glycemia ratio", the positive response to tolbutamide in half of the hyperosmolar cases suggests a less complete pancreatic deficiency than in keto-acidosis. The plasma high free fatty acid and triglyceride levels suggest that the lack of ketosis is not due to inhibition of lipolysis but could be a consequence of inhibition of hepatic ketogenesis.