The isolated perfused rat liver as an experimental model.

Intrinsic liver function may be specifically studied using the isolated perfused liver system. In this report, the metabolic characteristics of the perfused rat liver are described in response to lactate (5 mM) and ammonia (10 mM) loading. These conditions are analogous to the increased substrate availability that accompanies some acute disease states such as trauma. Glucose production (490 +/- 85 nm/gm liver/min) was constant during a 90-minute perfusion whereas albumin secretion exhibited a biphasic kinetic profile in the absence of exogenous amino acids. Liver oxygen consumption (VO2) was responsive to substrate loading as evidenced by a 20 to 60 per cent initial increase in VO2. The authors conclude that a large portion of hepatic VO2 may normally be directed toward substrate clearance. Additionally, although hepatic secretory protein synthesis persists despite the limitation of nutrient amino acid supply, the kinetics of secretion are complex.