Studies of insulin resistance in adipocytes induced by macrophage mediator.

An apparent insulin resistance is noted in 3T3-L1 adipocytes after the addition of an endotoxin-induced mediator from macrophages. Examination at the level of the insulin receptor has revealed that the mediator does not effect either the functional ability of the cells to bind insulin or the ability of insulin to stimulate the uptake of glucose. The resistance appears to reflect a post-receptor interference with the insulin-induced biosynthesis of the anabolic enzymes, acetyl Co-A carboxylase and fatty acid synthetase, which are required for the conversion of glucose into storage lipid. These studies offer a new in vitro model for investigating the molecular basis of insulin resistance.