Acquired alterations in vitamin D metabolism in the acidotic state

Abstract
Classic (type I) renal tubular acidosis in children is attended by growth retardation and rickets, abnormalities that can be corrected by alkali therapy alone. We have employed the NH4Cl-treated rachitic chick as a model to investigate vitamin D metabolism in the acidotic state. NH4Cl ingestion for 96 h was associated with a rise in serum calcium, a significant decrease in blood pH (7.42+0.08 vs 7.30±0.08,P3H]1,25(OH)2D3 following [3H]25OHD D3 injections, and enhanced metabolic clearance of administered [3H]1,25(OH)2D3. The data collectively suggest that metabolic acidosis in the chick alters the production and degradation of 1,25(OH)2D3.