Effects of 1,25-dihydroxycholecalciferol administration on the rat renal vitamin K-dependent carboxylating system.
We have shown previously that the in vitro activity of the renal vitamin K-dependent gamma-glutamyl carboxylase toward synthetic oligopeptide substrates is stimulated by administration of either parathyroid hormone (PTH) or 1,25-dihydroxycholecalciferol [1,25(OH)2D3] to rats [(1983) J. Biol. Chem. 258, 12783-12786]. Here we report that administration of 1,25(OH)2D3 to rats increases their levels of endogenous carboxylase substrate as well. Rats fed a vitamin D-deficient diet had highly elevated serum PTH levels while vitamin D-replete animals had undetectable levels. Furthermore, since PTH increases 1,25(OH)2D3 levels by stimulating renal 25-hydroxyvitamin D-1 alpha-hydroxylase, it is very likely that the stimulatory effects of PTH on the renal vitamin K-dependent carboxylating system are mediated by 1,25(OH)2D3.
D000818:Animals; D002112:Calcifediol / Q000097:blood; D002117:Calcitriol / Q000097:blood / Q000494:pharmacology*; D002118:Calcium / Q000097:blood; D019735:Carbon-Carbon Ligases; D066298:In Vitro Techniques; D007668:Kidney / Q000201:enzymology*; D007700:Kinetics; D008025:Ligases / Q000378:metabolism*; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains; D014812:Vitamin K / Q000494:pharmacology*
D010281:Parathyroid Hormone; D014812:Vitamin K; D008025:Ligases; D019735:Carbon-Carbon Ligases; C020660:glutamyl carboxylase; D002117:Calcitriol; D002112:Calcifediol; D002118:Calcium