An Acute Infusion of Lactic Acid Lowers the Concentration of Potassium in Arterial Plasma by Inducing a Shift of Potassium into Cells of the Liver in Fed RatsCheema-Dhadli S. · Chong C.-K. · Kamel K.S. · Halperin M.L.
Division of Nephrology, St. Michael’s Hospital, Toronto, Ont., Canada
Background: Potassium (K+) input occurs after meals or during ischemic exercise and is accompanied by a high concentration of L-lactate in plasma (PL-lactate). Methods: We examined whether infusing 100 µmol L-lactic acid/min for 15 min would lead to a fall in the arterial plasma K+ concentration (PK). We also aimed to evaluate the mechanisms involved in normal rats compared with rats with acute hyperkalemia caused by a shift of K+ from cells or a positive K+ balance. Results: There was a significant fall in PK in normal rats (0.25 mM) and a larger fall in PK in both models of acute hyperkalemia (0.6 mM) when the PL-lactate rose. The arterial PK increased by 0.8 mM (p < 0.05) 7 min after stopping this infusion despite a 2-fold rise in the concentration of insulin in arterial plasma (PInsulin). There was a significant uptake of K+ by the liver, but not by skeletal muscle. In rats pretreated with somatostatin, PInsulin was low and infusing L-lactic acid failed to lower the PK. Conclusions: A rise in the PL-lactate in portal venous blood led to a fall in the PK and insulin was permissive. Absorption of glucose by the Na+-linked glucose transporter permits enterocytes to produce enough ADP to augment aerobic glycolysis, raising the PL-lactate in the portal vein to prevent postprandial hyperkalemia.
© 2012 S. Karger AG, Basel
Published online: April 28, 2012
Number of Print Pages : 9
Number of Figures : 7, Number of Tables : 4, Number of References : 32
Vol. 120, No. 2, Year 2012 (Cover Date: May 2012)
Journal Editor: Kleta R. (London)
ISSN: 1660-2137 (Print), eISSN: 1660-2137 (Online)
For additional information: http://www.karger.com/NEP