RESEARCH PROJECTS

Development of Strategies to Increase Peripheral Insulin
Responsiveness in Dietary-Induced Insulin Resistant Horses

The phenomenon of insulin resistance is a condition of reduced insulin mediated glucose uptake by peripheral tissues, primarily muscle and fat. As a result of hyperglycemia, pancreatic secretion of insulin increases and the resultant hyperinsulinemia may characterize insulin resistance. 

In the horse, insulin resistance has been associated with the development of several pathological conditions, including laminitis and osteochondrosis dissecans lesions (OCD).  The exact role that insulin resistance plays in the development of these and other diseases remains to be established.

Obesity and inflammation are key factors that lead to insulin resistance.  In each condition, increases in circulating concentrations of small molecular weight proteins, produced by white blood cells and fat tissue, are thought to play a key role in the development of insulin resistance.  The similarity in the mechanism between the development of insulin resistance associated with inflammation and obesity has led to the widely held view that obesity represents a condition of mild inflammation. 

In obese horses, insulin sensitivity can be increased by exercise and weight loss.  Since in some situations exercise of insulin resistant horses may not be possible current studies are focused on pharmacological approaches to improve insulin sensitivity. 

In addition, obesity and insulin resistance are associated with abnormal length estrous cycles. A related objective of these studies is to determine whether increased insulin sensitivity leads to the development of estrous cycles with a normal physiological duration for this species.