resistin

Resistin is an adipokine named for its apparent ability to make the body “resist” insulin. It was discovered as a fat-derived hormone that, in mice, seemed to be a direct link between obesity and difficulty controlling blood sugar.

In rodents, resistin is secreted mainly by fat cells and raises blood glucose by promoting insulin resistance, especially in the liver. It also has pro-inflammatory effects. These findings made it an attractive candidate to explain why excess fat impairs insulin action, and it remains a useful model for thinking about adipose-driven metabolic disease.

An important honest caveat: the human story is more complicated. In people, resistin comes largely from immune cells (monocytes and macrophages) rather than fat cells, and its role in human insulin resistance is debated and far less clear than in mice. Resistin illustrates a recurring lesson in endocrinology — a hormone’s biology can differ substantially between species, so animal results must be confirmed in humans.