Metabolic effects of biosynthetic human proinsulin in type 2 diabetes mellitus

Due to a longer plasma half-life and half-time of action on glucose metabolism biosynthetic human proinsulin was thought to be an alternative to long-acting insulin preparations. To test this hypothesis we studied 23 type 2 diabetic patients who could no longer be treated sufficiently with oral hypoglycaemic agents. After an initial 1 week phase during which all patients received protamine bound insulin twice daily, the patients either continued on NPH insulin (Group A, n = 11) or were randomly switched to human proinsulin (Group B, n = 12). Glucose profiles and peripheral and hepatic insulin sensitivity (euglycaemic clamp: 120 mU m-2 min-1) were measured at the end of the initial period (Time 1) and 1 week later (Time 2). The insulin-mediated glucose disposal (RD) was not changed after either treatment (group A: 176 +/- 18 vs. 192 +/- 19 mg m-2 min-1; group B: 175 +/- 15 vs. 174 +/- 12 mg m-2 min-1 for times 1 and 2, respectively, NS). Suppression of hepatic glucose output (HGO) was complete in both groups at both times. Fasting blood glucose levels (FBG) and basal HGO were equally low at times 1 and 2 (group A: FBG 118 vs. 123 mg dl-1, BHGO 81 vs. 79 mg m-2 min-1; group B: FBG 118 vs. 106 mg dl-1, BHGO 87 vs. 84 mg m-2 min-1; NS).(ABSTRACT TRUNCATED AT 250 WORDS)