A paradoxical effect of chlorpropamide on the plasma glucose and immunoreactive insulin response to intravenous glucose in normal dogs

Effect of glipizide treatment on various aspects of glucose, insulin, and lipid metabolism in patients with noninsulin-dependent diabetes mellitus

Glipizide is a "second generation" sulfonylurea compound, and in this study the effects of several months of glipizide treatment on various aspects of glucose, insulin, and lipid metabolism were documented in 23 patients with noninsulin-dependent diabetes mellitus. Mean (+/-SEM) fasting plasma glucose concentration decreased (p less than 0.001) from 264 +/- 12 to 172 +/- 10 mg/dl, and a similar decrement in postprandial glucose concentration was also seen following glipizide therapy. Mean plasma triglyceride concentration was also lower (p less than 0.05) after glipizide treatment and was associated with modest reciprocal changes in plasma cholesterol (lower) and high-density lipoprotein cholesterol (higher) concentrations. Although neither of these latter two effects was statistically significant, the net effect was to lead to a significant (p less than 0.02) increase in the ratio of high-density lipoprotein cholesterol to total cholesterol. Furthermore, significant relationships were noted between the improvement in diabetic control in glipizide-treated patients and lowering of both very low-density lipoprotein-triglyceride (r = 0.69, p less than 0.001) and low-density lipoprotein-cholesterol (r = 0.54, p less than 0.02) concentrations. Finally, glipizide treatment was associated with improvements in both the plasma insulin response to mixed meals and estimates of in vivo insulin-stimulated glucose utilization. Although both of these changes were likely to have contributed to the ability of glipizide to lower plasma glucose concentrations, only the increase in in vivo insulin action correlated with the improvement in diabetic control (r = 0.69, p less than 0.001).

Therapeutic approaches to reducing insulin resistance in patients with noninsulin-dependent diabetes mellitus

Patients with noninsulin-dependent diabetes mellitus (NIDDM) are characterized by a loss of the normal ability of insulin to stimulate glucose uptake. The effects of diet, exercise, sulfonylurea compounds, and exogenous insulin on in vivo insulin-stimulated glucose uptake have been reviewed in this presentation. Although there is still a great deal to learn about the manner in which these various forms of treatment affect in vivo insulin action, the available information provides a rational framework for therapeutic attempts to enhance insulin sensitivity in patients with NIDDM.