MEASUREMENT OF INSULIN-RESISTANCE IN OBES E HYPERANDROGENIC WOMEN USING THE INSULIN TOLERANCE-TEST

Background: Insulin tolerance test is a simple method to measure insul in resistance that has a good correlation with glucose clamp studies. Aim: To use the insulin tolerance test to detect differences in insuli n sensitivity between healthy and obese hyperandrogenic women and to c orrelate its results with those of the minimal model intravenous gluco se tolerance test. Patients and methods: Five healthy women aged 27+/- 7 years old with a body mass index of 21+/-2 kg/m(2) and six hyperandr ogenic women aged 25+/-4 years old with a body mass index of 40+/-5 kg /m(2) were studied after a 10 hours fast. For the insulin tolerance te st 0.1 U/kg of crystalline insulin were injected intravenously and blo od samples were drawn to measure glucose at -5,0,3,5,10 and 15 min, af ter the injection. Insulin resistance was calculated using the slope o f descending blood glucose levels (SI1). For the intravenous glucose t olerance test, 29 blood glucose samples were obtained after an intrave nous injection of 0.3 g glucose/kg followed by an injection of 0.02 U/ kg of crystalline insulin. Insulin sensitivity (SI2) was calculated us ing Bergman's minimal model. Results: Healthy women had a SI1 of 0.58 (range 0.53-0.63) and a SI2 of 7.9 x 10(4) x min(-1)/mu U/ml (range 4. 15-9.11). For hyperandrogenic women were 0.18 (range 0.06-0.29) and (0 .9 x 10(4) x min(-1)/mu U/ml (range 0.46-1.79), respectively. Both met hods had a positive correlation coefficient of 0.859 (p<0.001). Conclu sions: Insulin tolerande test is a good method to measure insulin resi stance and has a good correlation with the frequently sampled intraven ous glucose tolerance test.