Insulin resistance and mechanical dysfunction in hearts of Wistar rats with streptozotocin-induced non-insulin-dependent diabetes mellitus.

The present study correlates the insulin resistance seen in the myocardium of rats with streptozotocin-induced non-insulin-dependent diabetes mellitus with insulin secretory defects, hyperglycaemia and disease duration. Two-day-old male Wistar rats were given a bolus injection of streptozotocin (0.09 mg/g body weight) which caused glucose intolerance when these animals reached adulthood. Although these rats developed a progressive resistance to the actions of insulin in the heart this did not correlate with the development of glucose intolerance. However, a correlation was seen with a shift in insulin secretory response from hyper- to hypo-secretion which developed between 6 and 14 months of age. Moreover, this shift in secretory pattern can be associated with the onset of a cardiac mechanical malfunction.