[Body mass index influence in the insulin action mechanisms]

Improve the knowledge of the "in vitro" insulin action in healthy subjects with different body mass index (BMI), in order to know the role of obesity in the diabetes mellitus.

In 12 healthy subjects with different BMI and normal oral glucose test we made a gluteal biopsy to obtain adipose tissue. In the isolated adipocytes we studied the interaction of insulin with its receptor and the glucose transport.

BMI was not correlated with the maximal specific 125I-insulin binding but was negative when correlated with the glucose transport in basal situation (r = -0.63, p < 0.05) as well as when stimulated with insulin (r = -0.67, p < 0.05), when the results were expressed as number of cells. When the data were expressed as surface, BMI was negative correlated with the percentage of maximal specific 125I-insulin binding (r = -0.81, p < 0.05), and also with the basal glucose transport (r = -0.69, p < 0.05) and stimulated with insulin (r = -0.77, p < 0.01).

The increase of BMI is an important diabetogenic agent, acting at receptor as well as at postreceptor level, and the data should be expressed according to the cellular diameter rather than to the number of cells in subjects with different BMI. A cutting point was established at the 30 BMI level after which the described alterations could be observed.