Concurrent measurement of plasma levels of vitamin D3 and five of its metabolites in normal humans, chronic renal failure patients, and anephric subjects
Lambert, P.W.; DeOreo, P.B.; Hollis, B.W.; Fu, I.Y.; Ginsberg, D.J.; Roos, B.A.
Journal of Laboratory and Clinical Medicine 98(4): 536-548
1981
ISSN/ISBN: 0022-2143 PMID: 6270222 Document Number: 168535
Newly developed and established techniques were used for the estimation of a broad spectrum of cholecalciferol metabolites in plasma, including cholecalciferol and 25-hydroxycholecalciferol-26,23- beta -lactone (25HCC-lactone), in normal human subjects, chronic renal failure patients and anephric subjects. The methods described were methanol-methylene chloride extraction. Lipidex-5000 chromatography with stepwise gradient elution, normal-phase high-performance liquid chromatography with concave gradient elution and sensitive ligand-binding estimations. The results of the study strongly suggest an extrarenal source for 24,25- and 25,26-dihydroxycholecalciferol and indicate that 25HCC-lactone and 1,25-dihydroxycholecalciferol may be produced entirely in the human kidney. Significant reductions of nondetectable plasma cholecalciferol in the renal disease patients may reflect abnormalities in the hepatobiliary-intestinal or cutaneous metabolism of vitamin D, or both.