Investigation of the prolonged hypoglycemic effect of human proinsulin in diabetes mellitus.
Human proinsulin possesses a clear hypoglycemic effect, the extent and kinetics of which were investigated in 8 insulin dependent diabetics. In addition, to adequate therapy with a controlled-release insulin, each patient received i.v. injections of insulin (e U) and proinsulin (9 U) on separate test days. After 9 U of proinsulin, the blood glucose decrease was delayed in comparison to 3 U of insulin. However, it reached identical maximum blood glucose decrease values. The elimination kinetics of proinsulin are delayed compared to insulin. There is a linear relation between the time and the reciprocal value of the measured insulin immuno-reactivity. The hypoglycemic effect of proinsulin which is protracted for hours corresponds to that of an extreme controlled-release insulin. Under certain conditions, proinsulin might therefore prove effective in the long-term treatment of the insulin-dependent diabetes mellitus.