Role of System Gly in glycine transport in monolayer cultures of liver cells

Abstract

The high-affinity component of glycine uptake by the hepatoma cell line HTC and by the ordinary rat hepatocyte corresponds to System Gly, the agency serving for glycine uptake by pigeon red blood cells and rabbit reticulocytes, and at most to only a minor extent to System ASC. This component was identified in HTC by its sensitivity to inhibition by sarcosine but scarcely by 2-(methylamino) isobutyric acid, by its insensitivity to lowering of the pH, and by the unique relation of its rate to the square of the Na+ concentration. The identity of the low-affinity component with System A was confirmed by opposite properties, and by its stimulation by insulin or amino acid starvation. Both components differed sharply from the System ASC uptake as measured with threonine.