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.
Mitchell L. Halperin, MD
Division of Nephrology, St. Michael’s Hospital, Room 408
Kenan Research Building, LKSI 30 Bond Street
Toronto, ON M5B 1W8 (Canada)
Tel. +1 416 864 5292, E-Mail firstname.lastname@example.org
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