AJP - Renal Physiology, Vol 248, Issue 6 796-F803, Copyright © 1985 by American Physiological Society
Role of citrate excretion in acid-base balance in diuretic-induced alkalosis in the rat
A. M. Kaufman, C. Brod-Miller and T. Kahn
Studies were performed to assess the role of changes in the excretion of
citrate, a metabolic precursor of bicarbonate, in acid-base balance in
diuretic-induced metabolic alkalosis. Rats on a low-chloride diet with
sodium sulfate added were studied during a base-line period, 3 days of
furosemide administration, and 4 days post-furosemide. During the period of
furosemide administration, net acid excretion and plasma bicarbonate
concentration increased. In the post-furosemide period, net acid excretion
remained higher than base line but plasma bicarbonate concentration did not
increase further. Citrate excretion was significantly higher in the
post-furosemide period than in base line. Studies substituting sodium
neutral phosphate or sodium bicarbonate for dietary sodium sulfate
demonstrated greater increases in net acid excretion post-furosemide and,
again, no increase in plasma bicarbonate concentration during this period.
Citrate excretion was greater than in the sulfate group. The increment in
citrate excretion was proportional to the base "load," defined with respect
to changes in net acid excretion and/or dietary bicarbonate. Thus, in these
studies alterations of base excretion in the form of citrate play an
important role in acid-base balance during diuretic-induced metabolic
alkalosis.
