The Action of Corticosteroids on the Renal Excretion and Utilization of Citric Acid

Abstract

During treatment with steroid hormones the tubular reabsorption of citric acid (cit.) increases, and the endogenous citric acid clearance is reduced. This is attributed to increased diffusion of citric acid from the tubular lumen to the renal tissue. With simultaneous administration of corticosteroids and anabolic steroids the tubular reabsorption of citric acid becomes normal. Steroid hormones block the renal synthesis of cit. and the renal utilization of cit. becomes identical with the amount of cit. reabsorbed in the tubules. Blockade of the synthesis of cit. is attributed to the inhibitory effect of steroid hormones on enzyme systems.

The Renal Excretion and Tubular Reabsorption of Citric Acid in Renal Tubular Acidosis

“…Our results confirm previous observations that the pattern of Ci metabolism differs from the decreased Ci metabolism achieved after inhibition of carboanhydrase (1, 6). Our findings support the opinion that carboanhydrase activity is normal in RTA.…”

“…Glomemlar filtration rate (GFR) was measured as inulin clearance, and renal plasma flow (RF'F) was calculated on the basis of paraaminohippuric acid (PAH) clearance and the extraction rate of PAH. The chemical methods used and the formulas for calculation have been described previously (6). Table I shows the average values for 2-3 consecutive examination periods.…”

“…Urinary citrate (Ci) excretion is decreased in renal tubular acidosis (RTA) (2,3) and after acetazoleamide blockade of the enzyme carboanhydrase (4,6). It has not been demonstrated that correction of the metabolic acidosis in RTA normalizes Ci excretion.…”