L-Serine Uptake by Trout ( Salmo Trutta ) Red Blood Cells: the Effect of Isoproterenol

Abstract

We studied the uptake of L-serine by trout red blood cells and the effect of a -adrenergic agonist (isoproterenol) on this process. The results obtained indicate that L-serine is taken up by these cells by means of a concentrative process. The uptake seems to be mediated both by a sodium-dependent process and by a sodium-independent process. The sodium-dependent uptake is mediated by a transport system that probably belongs to the ASC system family. Isoproterenol exerts an inhibitory effect on L-serine uptake. This effect is dose-dependent. It is proposed that the inhibitory effect of isoproterenol is mediated by a rise in the intracellular sodium concentration and/or changes in cell volume.