Abstract
Recently, the 24-hydroxylase enzyme of 25-hydroxyvitamin D3 was purified from rat and chick kidney, and its complementary DNA was cloned. The length of the rat 24-hydroxylase gene is about 15 kbp with 12 exons. Cloning of the 24-hydroxylase gene made it possible to examine the mechanism of regulation of vitamin D metabolism at the gene level. Expression of renal 24-hydroxylase mRNA is regulated by a balance of plasma parathyroid hormone and 1 alpha,25-dihydroxyvitamin D3 levels, whereas intestinal 24-hydroxylase mRNA is regulated mainly by plasma 1 alpha,25-dihydroxyvitamin D3. This article reviews recent progress in understanding the molecular aspects of vitamin D metabolism.
MeSH terms
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Animals
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Calcitriol / blood
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Chickens
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Cholestanetriol 26-Monooxygenase
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Cloning, Molecular
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Cytochrome P-450 Enzyme System / biosynthesis
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Cytochrome P-450 Enzyme System / genetics
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Exons
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Gene Expression
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Homeostasis
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Humans
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Kidney / metabolism*
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Parathyroid Hormone / blood
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RNA, Messenger / analysis
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RNA, Messenger / biosynthesis
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Rats
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Steroid Hydroxylases / biosynthesis
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Steroid Hydroxylases / genetics
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Steroid Hydroxylases / metabolism
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Vitamin D / metabolism*
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Vitamin D3 24-Hydroxylase
Substances
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Parathyroid Hormone
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RNA, Messenger
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Vitamin D
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Cytochrome P-450 Enzyme System
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Steroid Hydroxylases
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CYP27A1 protein, human
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Cholestanetriol 26-Monooxygenase
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Vitamin D3 24-Hydroxylase
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Calcitriol