Isotopic labeling affects 1,25-dihydroxyvitamin D metabolism

Journal Article · Tue Feb 07 04:00:00 EST 1989 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00429a049· OSTI ID:5904720

Halloran, B P; Bikle, D D; Castro, M E; Gee, E

Isotope substitution can change the biochemical properties of vitamin D. To determine the effect of substituting 3H for 1H on the metabolism of 1,25(OH)2D3, we measured the metabolic clearance rate and renal metabolism of unlabeled and 3H-labeled 1,25(OH)2D3. Substitution of 3H for 1H on carbons 26 and 27 (1,25(OH)2(26,27(n)-3H)D3) or on carbons 23 and 24 (1,25(OH)2(23,24(n)-3H)D3) reduced the in vivo metabolic clearance rate of 1,25(OH)2D3 by 36% and 37%, respectively, and reduced the in vitro renal catabolism of 1,25(OH)2D3 by 11% and 54%, respectively. Substitutions of 3H for 1H on carbons 23 and 24 as opposed to carbons 26 and 27 reduced conversion of (3H)1,25(OH)2D3 to (3H)1,24,25(OH)2D3 by 25% and to putative 24-oxo-1,23,25-dihydroxyvitamin D3 by 1600%. These results indicate that substitution of 3H for 1H on carbons 26 and 27 or on carbons 23 and 24 can reduce the metabolic clearance rate and in vitro metabolism of 1,25(OH)2D3 and quantitatively alter the pattern of metabolic products produced.

• Research Organization: Univ. of California, San Francisco (USA)
• OSTI ID: 5904720
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 28:3; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BODY
CHEMICAL PROPERTIES
CLEARANCE
ISOTOPE APPLICATIONS
KIDNEYS
LABELLED COMPOUNDS
LABELLING
MAMMALS
METABOLISM
ORGANS
RATS
RODENTS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES
VITAMIN D
VITAMINS