AJP - Renal Physiology, Vol 234, Issue 6 466-F471, Copyright © 1978 by American Physiological Society
Magnesium metabolism in potassium-depleted rats
C. G. Duarte
In rats, a diet depleted of potassium caused a significant hypokalemia and
hypermagnesemia, a diuresis and natriuresis, a decrease in urinary and
fecal excretion of potassium, a magnesiuria, and a decrease in fecal
excretion of magnesium. Balance studies revealed that potassium metabolism
was negative in potassium-depleted rats and that magnesium metabolism was
positive and higher than in control rats. In potassium-depleted rats,
potassium and magnesium contents in muscle were reduced, whereas the sodium
level was increased and plasma aldosterone was significantly lower.
Therefore, the elevation in plasma concentration of magnesium induced by a
diet poor in potassium is the result of a more positive metabolic balance
of magnesium and of shifting of magnesium from the tissue into the plasma
compartment. Results of additional preliminary studies support the
possibility that the hypermagnesemia may be mediated through the depression
in mineralocorticoid activity induced by the depletion of potassium.
