Role of kidney tissue in the production of 25-hydroxyvitamin D3-26,23-lactone and 1 alpha, 25-dihydroxyvitamin D3-26,23-lactone.

Autor: Tanaka, Y, Wichmann, J K, Paaren, H E, Schnoes, H K, DeLuca, H F
Zdroj: Proceedings of the National Academy of Sciences of the United States of America; November 1980, Vol. 77 Issue: 11 p6411-6414, 4p
Abstrakt: Labeled 25-hydroxyvitamin D3-26,23-lactone was isolated from the serum of vitamin D-repleted rats given [3 alpha-3H]-25-hydroxyvitamin D324 hr prior to sacrifice. The metabolite was identified by cochromatography with the authentic lactone on straight-phase and reversed-phase high-performance liquid chromatography. Production of the lactone was abolished by nephrectomy indicating that the kidney is the site of synthesis. Homogenate of kidneys from chickens given large doses of vitamin D can carry out in vitro production of the lactone from 25-hydroxyvitamin D3. When 1 alpha, 25-dihydroxyvitamin D3 was used as substrate, this system produced only traces of a compound believed to be 1 alpha, 25-dihydroxyvitamin D3-26,23-lactone. However, incubation of rachitic chicken kidney homogenates with 25-hydroxyvitamin D3-26,23-lactone produced substantial amounts of a compound that has been identified by mass spectrometry as 1 alpha, 25-dihydroxyvitamin D3-26,23-lactone. Thus, the development of a functional group on C-26 and eventual lactone formation takes place in kidney by a system acting on 25-hydroxyvitamin D3.
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