Effect of 1,25-dihydroxyvitamin D deficiency on the metabolic clearance rate of 1,25-dihydroxyvitamin D3: studies using pigs with vitamin D-dependent rickets type 1.
We have used pigs with inherited vitamin D-dependent rickets type 1 to study the effect of 1,25-dihydroxyvitamin D deficiency on the metabolic clearance rate of 3H-1,25-dihydroxyvitamin D3 infused to steady-state levels in plasma. Plasma levels of 1,25-dihydroxyvitamin D were 24 +/- 1 (SEM) pmol/l in the hypocalcaemic, homozygous piglets and 196 +/- 27 pmol/l in their normocalcaemic, heterozygous siblings. The metabolic clearance rate of 1,25-dihydroxyvitamin D3 was the same in both normal heterozygous (0.90 +/- 0.02) and hypocalcaemic, homozygous piglets (0.90 +/- 0.01 ml-1 min-1 kg-1 metabolic body size). We conclude that a deficiency of circulating 1,25-dihydroxyvitamin D does not influence the clearance of 1,25-dihydroxyvitamin D3 from the circulation of pigs.
D000818:Animals; D002117:Calcitriol / Q000097:blood / Q000172:deficiency*; D006996:Hypocalcemia / Q000097:blood; D007015:Hypophosphatemia, Familial / Q000097:blood*; D008657:Metabolic Clearance Rate; D013552:Swine; D014808:Vitamin D Deficiency / Q000097:blood*
D002117:Calcitriol