Non-insulin-dependent diabetes mellitus
As both insulin secretion and insulin action (NIDDM) is, according to the World Health are controlled genetically, mutations in genes Organization (WHO) definition, diagnosed on encoding for either hormone secretion, or its the basis of raised plasma glucose that can activity at the target cell, could, in theory, be be controlled without exogenous insulin. As the primary event in NIDDM. Equally possible insulin secretion is controlled almost entirely is the hypothesis that environmental insults by a feedback of plasma glucose levels on the affect either insulin secretion or sensitivity, pancreatic โค-cells, hyperglycaemia can arise thereby setting up the cycle of events that cause either from insufficient insulin secretion or the disease. A genetic component of the coninadequate uptake of glucose (i.e., insulin dition is suggested by the fact that NIDDM resistance of the tissues). The condition of insushows familial aggregation; 4 the contribution lin resistance has attracted considerable attenof environmental factors is demonstrated by tion in recent years. Although there can be no observations that obesity or age affects glucose doubt that what ultimately occurs in NIDDM is tolerance. Current opinion is that both types of a lack of sufficient insulin to meet the needs factors confer risk for NIDDM and that the of a particular individual, there are important combination of environmental injury acting on issues relating to the condition that need clarigenetic predisposition causes NIDDM. fying: whether insulin resistance is more important than defective insulin secretion in the pathogenesis of NIDDM; whether the mech-3. POPULATION STUDIES anism is mediated genetically or environmentally; whether insulin resistance is also involved in the pathogenesis of hypertriglyceridaemia, A cross-sectional study investigated insulin thrombotic tendency and hypertension; and resistance in individuals who had either normal whether hyperinsulinaemia is a risk factor for glucose tolerance (NGT) or manifest NIDDM. 5 atherosclerosis.
This study utilized the euglycaemic insulin clamp technique, and insulin-mediated glucose disposal was used as a measure of insulin sen-Addressee for correspondence: Dr E Ferrannini, sitivity. The results showed that there was a