title: Reduction of circulating 25-hydroxyvitamin D by antipyrine.
abstract: 1 Twenty-four Asian vegetarians had significantly lower 25-hydroxyvitamin D (25-OHD) levels and longer antipyrine half-lives than twenty white non-vegetarians (P less than 0.001). 2 Treatment with oral antipyrine over 4 or 5 weeks in seven vegetarian Asians and five racially different non-vegetarians increased drug oxidation significantly in both groups as measured by a fall in antipyrine half-lives and a rise in serum gamma-glutamyltranspeptidase levels and urinary 6 beta-hydroxycortisol/17-hydroxycorticosteroid ratios. 3 Antipyrine treatment produced a fall in circulating 25-hydroxyvitamin D of around 60% in all subjects in whom pretreatment levels could be measured, independent of race and diet. 4. In the Caucasian non-vegetarian group 1,25 dihidroxyvitamin D levels, the most active metabolite of vitamin D, were also measured and remained unaltered despite a substantial fall in 25-hydroxy substrate. 5 The acute fall in 25-hydroxyvitamin D concentration with a maintained level of 1,25 dihidroxyvitamin D may represent the early changes of drug-induced osteomalacia.
mesh_terms: D000328:Adult; D000983:Antipyrine / Q000378:metabolism / Q000494:pharmacology*; D001208:Asia / Q000208:ethnology; D003864:Depression, Chemical; D014676:Diet, Vegetarian; D005260:Female; D006207:Half-Life; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood*; D007700:Kinetics; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D013997:Time Factors; D006113:United Kingdom
chemical_list: D006887:Hydroxycholecalciferols; D000983:Antipyrine