April 2005

Insulin-Resistant? Lose The Leptin

The hormone leptin may be the difference between fat horses who are insulin-resistant and those that aren’t.

The risk may have more to do with hormones than the amount a horse may be overweight.

Insulin resistance (IR) is an important factor in some horses with obesity and recurrent, unexplained laminitis. Dubbed “metabolic syndrome,” it was largely assumed that obesity caused IR, and many studies seemed to back up the theory.

However, Dr. J.A. Cartmill at Louisiana State University has thrown a whole new light on the problem. The culprit may actually be leptin resistance.

Leptin is a hormone produced by fat cells that’s normally a signal to stop eating. Its release is triggered by high cellular supplies of glucose, at which point leptin “tells” the brain to stop eating. Leptin also regulates the metabolic rate, increasing resting energy expenditure. With resistance to the effects of…