No abstract

No abstract

Mg28 was used to explore the kinetics of magnesium distribution in 9 normal individuals and in 16 patients with various diseases. When Mg28 was given in 12–30 mEq of stable magnesium intravenously, plasma disappearance was rapid within the first several hours. In normal subjects a mean of 19.8% of the injected radioactivity was accounted for in the urine within 24 hours. Fecal excretion was negligible, although equilibration of Mg28 in bile occurred within 18 hours. The specific activities of plasma and urine stabilized by the 18th hour, and showed only a gradual decrease thereafter. Exchangeable magnesium contents in normal subjects ranged between 2.6 and 5.3 mEq/kg of body weight—less than 16% of the estimated total body content of magnesium. Mg28 exchanged very slowly with the stable ion in bone, muscle and erythrocytes. The results in patients with diabetes mellitus and hepatic diseases showed no striking differences from those obtained in normal subjects. Note: (With the Technical Assistance of Dale R. Harms and Jacqueline Z. Reardon) Submitted on October 5, 1959

1) Coexisting Mg and K deficiency may occur with greater frequency than has been previously appreciated. 2) Profound hypokalemia, or refractoriness to K repletion or coexisting hypokalemia and hypocalcemia should suggest the possibility of concurrent Mg and K depletion. 3) The identification and treatment of concurrent K and Mg depletion is especially important in patients with congestive heart failure because of problem of digitalis toxicity. 4) We believe that the role of magnesium in optimizing cardiac function remains to be elucidated, identification and treatment of coexisting Mg and K depletion will be facilitated by making serum Mg a routine electrolyte determination together with Na, K, CI, CO2.