Glucose-Induced Insulin Secretion in Dyslipidemic and Normolipidemic Patients With Normal Glucose Tolerance

The metabolic syndrome is highly prevalent in industrialized countries, where it represents a major public health burden due to the associated high risk of diabetes and cardiovascular disorders (1,2). High plasma triglyceride and low HDL cholesterol are prominent features of this syndrome (2,3). Large epidemiological studies have shown associations with both insulin resistance and low insulin secretion (4). The aim of this study was to evaluate whether the alterations of blood lipid, observed in the metabolic syndrome, are associated with alterations of insulin sensitivity or secretion in subjects with normal glucose tolerance. Glucose homeostasis was evaluated during a two-step hyperglycemic clamp in a group of dyslipidemic patients and in a group of normolipemic subjects of similar age and body weight. Subjects were studied after short-term administration of dexamethasone to evaluate reciprocal changes in insulin secretion and insulin sensitivity (5,6,7,8). Twenty dyslipidemic subjects (13 men and 7 women) with BMI >27 kg/m2 but having normal glucose tolerance, as documented by a standard oral glucose tolerance test (fasting glycemia 94 ± 7 mg/dl, 2-h glycemia 95 ± 17 mg/dl) (9), were selected for the study. They had a mean (±SD) age of 46.6 ± 7.6 years, body …