Metabolic detection of insulin abuse in sport

Insulin exhibits a number of actions involving metabolic regulation, body fluid control and cell proliferation. There are, however, insulin effects which directly affect muscle size and contractility and can potentially affect sport performance.  Insulin is the main anabolic hormone. It is responsible for the shift from the muscle catabolism associated with overnight fasting to the anabolic response to feeding. Insulin has the potential to stimulate synthesis and inhibit degradation of contractile proteins. In addition, it enhances inward amino acid transport. In skeletal muscle and at the whole body level, the insulin anabolic response is enhanced by protein/amino acid feeding. Muscle glycogen stores are the primary carbohydrate source during exercise. Exercise time to exhaustion directly correlates with muscle glycogen content. The acute hypoglycemic insulin effect is largely mediated by stimulation of muscle glucose uptake. Glycogen synthesis represents a large proportion of total glucose utilization in muscle. The aim of the project is to develop methodologies to detect insulin abuse through identification of metabolic markers of exogenous insulin administration.