Exogenous ATP and hepatic hemodynamics in the perfused rat liver.

The actions of exogenous adenosine triphosphate (ATP) on hepatic hemodynamics were analyzed in the isolated perfused rat liver. The effects of ATP (10, 40, and 160 microM) on hepatic circulatory resistances were determined from changes in portal vein flow, portal vein perfusion pressure, hepatic arterial perfusion pressure, and hepatic capacitance. ATP decreased portal vein flow under conditions of constant perfusion pressure, but it increased portal vein perfusion pressure under constant flow perfusion. ATP increased the resistance of the presinusoidal regions and reduced hepatic capacitance. Adenine derivatives including adenosine, adenosine monophosphate (AMP), adenosine diphosphate (ADP), and ATP also decreased portal vein flow; the order of vascular activity of the adenine compounds was ATP greater than ADP greater than AMP = adenosine. The shock-protective actions of ATP may reflect hepatic hemodynamic adjustments.