EFFECT OF MODERATE OBESITY ON GLUCOSE-TRANSPORT IN HUMAN MUSCLE

We have shown that maximally stimulated glucose transport is reduced i n in vitro incubated muscle of morbidly obese subjects. To investigate the possibility that a ''threshold'' of obesity exists, above which g lucose transport is significantly decreased, hormone (insulin, IGF-I, or IGF-II) stimulation of glucose transport was correlated with body m ass index using muscle biopsies from a group of 30 lean to obese femal es with BMI ranging from 16 to 40. There was a significant negative re lationship between stimulation for glucose transport and BMI (R= 0.765 ). These data suggest there is no obesity threshold for insulin resist ance in skeletal muscle but a continuous decline in glucose transport below a BMI of approximately 30 kg/m(2), after which insulin and the I GFs no longer stimulate glucose transport.