Hepatic Insulin Sensitivity

Hepatic insulin sensitivity is the degree to which the liver responds to insulin, particularly insulin's ability to suppress hepatic glucose production. In the fasting state, the liver helps maintain blood glucose through glycogen breakdown and gluconeogenesis. As insulin concentrations rise after eating, an insulin-sensitive liver reduces glucose production and promotes processes such as glycogen synthesis .^1,2

In metabolic research, hepatic insulin sensitivity is commonly assessed by measuring how strongly a given insulin concentration suppresses endogenous glucose production. Because the liver accounts for most endogenous glucose production under typical experimental conditions, measurements using glucose tracers can provide an estimate of hepatic insulin action. A hyperinsulinemic-euglycemic clamp combined with a glucose tracer is a widely used method for measuring this response .¹

Reduced hepatic insulin sensitivity is referred to as hepatic insulin resistance. In this state, insulin is less effective at suppressing hepatic glucose production, so the liver can continue releasing more glucose than would occur with normal insulin sensitivity despite the presence of insulin. This impaired suppression can contribute to elevated fasting and postprandial blood glucose concentrations .^1,2

Hepatic insulin sensitivity is distinct from whole-body or skeletal-muscle insulin sensitivity. Muscle insulin sensitivity primarily concerns insulin-stimulated glucose uptake by muscle, whereas hepatic insulin sensitivity concerns insulin's effects on liver metabolism. Insulin resistance can therefore differ between tissues, and hepatic, muscle, and adipose-tissue insulin sensitivity need not be impaired to the same degree .¹