Extra-renal 25-hydroxyvitamin D3-1 -hydroxylase in human health and disease
نویسندگان
چکیده
a Burns and Allen Research Institute, Division of Endocrinology, Cedars-Sinai Medical Center and David Geffen School of Medicine at UCLA, Los Angeles, CA 90048, USA b Division of Immunity and Infection, Institute of Biomedical Research, The University of Birmingham Medical School, Birmingham B15 2TT, UK c Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
منابع مشابه
Britain Stimulation of 1 , 25 - dihydroxyvitamin D 3 production by 1 , 25 - dihydroxyvitamin D 3 in the hypocalcaemic rat
Serum 1,25-dihydroxyvitamin D3 concentration and renal 25-hydroxyvitamin D 1 a-hydroxylase activity were measured in rats fed various levels of calcium, phosphorus and vitamin D3. Both calcium deprivation and phosphorus deprivation greatly increased circulating levels of 1,25-dihydroxyvitamin D3. The circulating level of 1,25-dihydroxyvitamin D3 in rats on a low-calcium diet increased with incr...
متن کاملThe 24-hydroxylation of 1,25-dihydroxyvitamin D3.
The production of 1,24,25-trihydroxyvitamin D3 in vivo in vitamin D-deficient rats has been demonstrated from either 25-hydroxyvitamin D3 or 1,25-dihydroxyvitamin D3. The stereochemical configuration of the hydroxyl on the 24 position of 1,24,25-trihydroxyvitamin D3 has also been unambiguously established to be R. Nephrectomy failed to eliminate the conversion of 1,25-dihydroxyvitamin D3 to the...
متن کاملMeasurement of mammalian 25 - hydroxyvitamin D 3 24 R - and la - hydroxylase ( 1 , 25 - dihydroxyvitamin D 3 / 24 , 25 - dihydroxyvitamin D / kidney / calcium ) YOKO TANAKA AND
An in vitro assay of mammalian 25-hydroxyvitamin D3 laand 24R-hydroxylases in kidney has been developed. It had been suggested that 25-hydroxyvitamin D binding protein present in mammalian blood and tissues inhibits the enzyme activities in cell-free preparations by binding the substrate 25-hydroxyvitamin D3 more strongly than the hydroxylases bind it. This inhibitory effect is overcome by the ...
متن کاملParathyroid hormone inhibits 25-hydroxyvitamin D3-24-hydroxylase mRNA expression stimulated by 1 alpha,25-dihydroxyvitamin D3 in rat kidney but not in intestine.
Using a cDNA probe for rat renal 24-hydroxylase, expression of its mRNA was compared in the rat kidney and intestine. Vitamin D-deficient rats received a single injection of 1 alpha,25-dihydroxyvitamin D3. Expression of 24-hydroxylase mRNA was first detected in the kidney at 3-h post-injection and increased thereafter. Similarly, 24-hydroxylase mRNA was expressed in the intestine after 1 alpha,...
متن کاملRegulation of the metabolism of 25-hydroxyvitamin D3 in primary cultures of chick kidney cells.
A primary chick kidney cell culture is described, capable of forming 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], 24,25-dihydroxyvitamin D3 [24,25(OH)2D3], and 1,24,25-trihydroxyvitamin D3 [1,24,25(OH)3D3] over several days. The apparent Km values were 0.125 microM for the 1-hydroxylase and 2.1 microM for the 24-hydroxylase. Exogenous 1,25(OH)2D3 decreased 1-hydroxylase and increased 24-hydroxylase ...
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