Metabolic effects of combination glipizide and human proinsulin treatment in NIDDM

The effects of 3 mo of treatment with a combination of glipizide and human proinsulin were studied in a small group of closely monitored patients. The patients had non-insulin-dependent diabetes mellitus (NIDDM) and poor glucose regulation, despite maximal sulfonylurea therapy. This was a randomized double-blind placebo-controlled trial in which there were three treatment groups who received either 20 mg glipizide given 30 min before breakfast and dinner and human proinsulin given subcutaneously at bedtime (n = 5), glipizide and human proinsulin placebo (n = 5), or glipizide placebo and human proinsulin (n = 5). Glycemic regulation was assessed by measurements of 24-h plasma glucose profiles and glycosylated hemoglobin. Our observations demonstrate that the combination of glipizide plus human proinsulin was more effective than either agent alone in controlling overall glycemia in patients with NIDDM. The data support the concept of use of an agent during the day that has its major effects postprandially and another agent at bedtime that is relatively hepatospecific.