Relationship between body fat distribution, serum insulin, and glucose tolerance in obese, non-diabetic women. Recent studies suggest that hyperinsulinemia and upper body obesity are predictive factors for the development of non-insulin-dependent diabetes mellitus. To further characterize the relationship between body fat distribution, serum insulin, and glucose tolerance an oral glucose tolerance test was performed in 48 obese, non-diabetic women. Fasting insulin levels were correlated to both total body fat calculated as body mass index (r = 0.58, p less than 0.001) and upper body fat distribution expressed as waist-to-hip ratio (WHR, r = 0.47, p less than 0.01). In the women with upper body fat localization (WHR greater than 0.90) significantly higher basal and glucose-stimulated insulin concentrations were established than in the women with a lower body type of obesity (WHR less than 0.78) (basal insulin 27.4 +/- 11.5 vs. 15.4 +/- 8.8 mU/l, p less than 0.05, insulin area 779 +/- 320 vs. 468 +/- 237 U, p less than 0.05). They also had impaired glucose tolerance (glucose area 925 +/- 139 vs. 633 +/- 147 U, p less than 0.01). Fasting triglyceride concentrations were correlated both with WHR (r = 0.63, p less than 0.001) and fasting insulin (r = 0.33, p less than 0.05) but not with BMI (r = -0.02, n.s.). A positive association was found between systolic and diastolic blood pressure and both WHR (r = 0.43 and r = 0.44 resp., p less than 0.01) and BMI (each r = 0.35, p less than 0.05). Interestingly, basal insulin was also associated with blood pressure (r = 0.30, p less than 0.1, and r = 0.40, p less than 0.01 resp.).(ABSTRACT TRUNCATED AT 250 WORDS)