24-hydroxylation of 1,25-dihydroxyvitamin D/sub 3/. [Rats, chickens]

Journal Article · Fri Feb 25 04:00:00 EST 1977 · J. Biol. Chem.; (United States)

OSTI ID:7122416

Tanaka, Y ^[1]; Castillo, L; DeLuca, H F; Ikekawa, N

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1. Univ. of Wisconsin, Madison

The production of 1,24,25-trihydroxyvitamin D/sub 3/ in vivo in vitamin D-deficient rats has been demonstrated from either 25-hydroxyvitamin D/sub 3/ or 1,25-dihydroxyvitamin D/sub 3/. The stereochemical configuration of the hydroxyl on the 24 position of 1,24,25-trihydroxyvitamin D/sub 3/ has also been unambiguously established to be R. Nephrectomy failed to eliminate the conversion of 1,25-dihydroxyvitamin D/sub 3/ to the 1,24,25-trihydroxyvitamin D/sub 3/, establishing that the 24-hydroxylase can be demonstrated in at least one organ in addition to kidney in contrast to the 1-hydroxylase. 1,24,25-trihydroxyvitamin D/sub 3/ can also be produced in vivo from 1..cap alpha..-hydroxyvitamin D/sub 3/ or from 24-hydroxyvitamin D/sub 3/, analogs of vitamin D/sub 3/ which are not naturally occurring. Using chick kidney mitochondrial preparations it has been demonstrated that the 24-hydroxylase is able to utilize 1,25-dihydroxyvitamin D/sub 3/ as a substrate whereas it is unable to utilize 1..cap alpha..-hydroxyvitamin D/sub 3/. In addition, the chick kidney 1-hydroxylase is known to convert 24,25-dihydroxyvitamin D/sub 3/ to the 1,24,25-trihydroxyvitamin D/sub 3/, but this hydroxylase is unable to act on the 24-hydroxyvitamin D/sub 3/. These results demonstrate that the renal vitamin D hydroxylases require that a hydroxyl be on the 25 carbon of the vitamin D molecule before it can be 1- or 24-hydroxylated.

• OSTI ID: 7122416
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 252:4; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BIOCHEMICAL REACTION KINETICS
BIRDS
CELL CONSTITUENTS
CHICKENS
CHOLECALCIFEROL
ENZYMES
FOWL
HYDROXYL RADICALS
HYDROXYLASE
KINETICS
MAMMALS
MITOCHONDRIA
ORGANOIDS
OXIDOREDUCTASES
RADICALS
RATS
REACTION KINETICS
RODENTS
STEREOCHEMISTRY
VERTEBRATES
VITAMIN D
VITAMINS