Calciferol metabolism and intestinal calcium transport in the chick with reduced renal function
Hartenbower, D.L.; Coburn, J.W.; Reddy, C.R.; Norman, A.W.
Journal of Laboratory and Clinical Medicine 83(1): 38-45
1974
ISSN/ISBN: 0022-2143 PMID: 4357619 Document Number: 75335
Day-old White Leghorn chicks were fed on a rachitogenic diet but were given unlabelled cholecalciferol by mouth in suboptimal doses, averaging 0.7 to 3.4 IU/day, between days 12 and 23 after hatching. Renal insufficiency was induced surgically at 20 to 22 days of age; 8 to 10 days later groups of sham-operated (control) and uraemic chicks were given either 20 IU of unlabelled cholecalciferol before estimation of intestinal Ca transport in vitro, or 3H- or 14C-labelled cholecalciferol. Compared with controls, uraemic chicks showed impaired intestinal Ca transport and a reduction in amounts in intestinal mucosa of a labelled metabolite chromatographically identical to 1,25-dihydroxycholecalciferol (1,25-DHCC), though there was no difference in the quantities of total labelled metabolites in plasma. The differences in labelled 1,25-DHCC present in intestinal mucosa were evident only in chicks whose intake of unlabelled cholecalciferol was less than 3 IU/day.