Potassium Migration and Amino Acid Transport

Alanine and Sodium Fluxes Across Mucosal Border of Rabbit Ileum

“…The importance of Na in the transmural transport and accumulation of sugars and amino acids by small intestine (2,3,(13)(14)(15)(16)(17)(18) and kidney (19,20) and in the accumulation of amino acids by a variety of cells (21)(22)(23)(24)(25)(26)37) is well established. Two hypotheses have been suggested to explain this Na requirement.…”

“…In 1952, Christensen and Riggs (36) reported that replacement of NaC1 with KC1 inhibited glycine uptake by Ehrlich ascites tumor cells. Although these authors, in a subsequent report (37), raised the possibility that glycine entry may be coupled to Na influx, they presented a number of arguments which favored an inhibitory role for extracellular K. It is clear from the studies of Kromphardt et al (21) that much of the effect observed by Christensen and Riggs can be attributed to the fact that glycine accumulation by ascites cells is a Na-dependent process. Several investigators have, however, reported specific inhibitory effects of high K media on both sugar (7) and amino acid accumulation (20,24) in excess of that which can be attributed simply to replacement of Na.…”

Characteristics of Threonine, Valine and Methionine Absorption in the Jejunum and Ileum of Sheep

“…Glycine ratios between the two sides revealed that a small concentration gradient had developed on the high potassium side. Correlation between potassium concentration in the cell and glycine absorption by that cell was 0.81 (Riggs et al, 1958). Lowering intracellular concentration of potassium lowers the amount of glycine absorbed.…”

“…Potassium has been shown to be related to amino acid absorption (Christensen and Oxender, 1960;Riggs et al, 1958). Nathans et al (1960) removed the potassium from the incubation medium without affecting the absorption of monoiodotyrosine, but increasing the potassium concentration to 0.02 molar or above did decrease uptake.…”

Proceedings of The Biochemical Society

“…In vivo studies on the rabbit are still in progress. Net uptake of glycine by ascites-tumour cells is known to be inhibited by lack of sodium or potassium, or in the presence of ouabain (Riggs, Walker & Christensen, 1958;Kromphardt, Grobecker,Ring & Heinz, 1963;Bittner & Heinz, 1963). We have now examined the effects of varying the sodium and potassium concentrations in the medium on the respective rates of glycine entry and efflux.…”