Dose-dependent effects of glycine, alanine, and glucose on hepatic bile secretion, oxygen consumption, and hemodynamics.

To assess the effects of a small (0.5%) and a large dose (5%) of glycine and alanine and of hypertonic glucose on hepatic bile secretion, oxygen consumption, and hemodynamics, experiments were performed on anesthetized pigs. Only the large dose of amino acids exerted significant changes. Glycine, alanine, and glucose reduced bile acid-dependent bile secretion gradually, which was nearly halved from a control value of 0.32 +/- 0.04 ml/min. Oxygen consumption was thereby continuously stimulated during amino acid and glucose infusion and increased from 448 +/- 132 mumol/min before to 995 +/- 226 mumol/min after the infusion of glycine, alanine, and glucose. Hepatic arterial blood flow increased from 214 +/- 14 ml/min to 238 +/- 14 ml/min after glycine infusion, whereas portal venous blood flow decreased from 542 +/- 50 ml/min to 481 +/- 47 ml/min. Total hepatic blood flow remained unchanged. Alanine and glucose provoked no further changes in hepatic blood flow. Bile secretion is a sensitive marker of hepatic metabolism, whereas hepatic blood flow is not a dominant regulator of bile secretion. Stimulation of hepatic metabolism is not followed by changes in total hepatic blood flow.