scholarly journals 25-Hydroxycholecalciferol-l-Hydroxylase Activity in Heat Stressed Laying Hens

1982 ◽  
Vol 61 (3) ◽  
pp. 586-588
Author(s):  
C.A. BAILEY ◽  
C.R. CREGER
Keyword(s):  
Laying Hens ◽  
Hydroxylase Activity ◽  
25 Hydroxycholecalciferol

scholarly journals Effect of oestrogen and 1,25-dihydroxycholecalciferol on 25-hydroxycholecalciferol metabolism in primary chick kidney-cell cultures

1978 ◽  
Vol 174 (1) ◽  
pp. 231-236 ◽  
Author(s):  
E Spanos ◽  
D I Barrett ◽  
K T Chong ◽  
I MacIntyre
Keyword(s):  
Vitamin D ◽  
Cell Cultures ◽  
Kidney Cell ◽  
Primary Cultures ◽  
Kidney Cells ◽  
Hydroxylase Activity ◽  
Experimental Conditions ◽  
Polar Metabolites ◽  
Chick Kidney ◽  
25 Hydroxycholecalciferol

Primary cultures of chick kidney cells convert 25-hydroxycholecalciferol into more-polar metabolites. Cells from vitamin D-deficient chicks have high 25-hydroxycholecalciferol 1 alpha-hydroxylase (1 alpha-hydroxylase) activity, but no 25-hydroxycholecalciferol 24-hydroxylase (24-hydroxylase) activity. Physiological concentrations of 1,25-dihydroxycholeclaciferol suppress 1 alpha-hydroxylase and induce 24-hydroxylase activity. The inhibition of 1 alpha-hydroxylase preceded the induction of 24-hydroxylase. In contrast, oestradiol-17 beta had no effect on the activity of either hydroxylase under a variety of experimental conditions. These results clearly demonstrate that 1,25-dihydroxycholecalciferol, but not oestrogen, acts directly on the kidney cells to regulate the metabolism of 25-hydroxycholecalciferol.

Submitochondrial localization of kidney 25-hydroxycholecalciferol 1α-hydroxylase in vitamin D repleted weanling guinea pigs

1987 ◽  
Vol 65 (7) ◽  
pp. 673-676 ◽  
Author(s):  
Xue Yan ◽  
Guy Charette ◽  
Edgard E. Delvin
Keyword(s):  
Vitamin D ◽  
Cytochrome C ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
Membrane Fraction ◽  
Hydroxylase Activity ◽  
Oxidoreductase Activity ◽  
Pig Kidney ◽  
Steroid Hydroxylases ◽  
25 Hydroxycholecalciferol

We have studied the submitochondrial localization of guinea-pig kidney 25-hydroxycholecalciferol 1α-hydroxylase. Treatment of the mitochondrial-enriched fraction with recrystallized digitonin produced mitoplasts bordered by a single membrane and with intact matrix. They contained nearly 90% of the 25-hydroxycholecalciferol 1α-hydroxylase activity and nearly 100% of the cytochrome-c: oxygen oxidoreductase. Amine: oxygen oxidoreductase activity remained mainly in the outer membrane fraction. These data show that 25-hydroxycholecalciferol 1α-hydroxylase has a distribution similar to that of steroid hydroxylases.

The effect of dietary calcium on the activity of 25-hydroxycholecalciferol-l-hydroxylase and Ca absorption in vitamin D-replete chicks

1977 ◽  
Vol 38 (1) ◽  
pp. 47-54 ◽  
Author(s):  
R. Swaminathan ◽  
Barbara A. Sommerville ◽  
A. D. Care
Keyword(s):  
Vitamin D ◽  
Dietary Intake ◽  
Specific Activity ◽  
Dietary Calcium ◽  
Duodenal Mucosa ◽  
List Type ◽  
Type Number ◽  
Hydroxylase Activity ◽  
Dietary Level ◽  
25 Hydroxycholecalciferol

1.As most of the studies on the regulation of renal 25-hydroxycholecalciferol-1-hydroxylase (25-HCC-1-hydroxylase) activity have been done in marginally-vitamin D-defieient animals and as it is known that vitamin D administration suppresses the specific activity of the 25-HCC-1-hydroxylase, it was decided to study the effect of dietary calcium on the activity of 25-HCC-1-hydroxylase and on Ca absorption in vitamin Dreplete chicks.2.Chicks, 10 d old, were given diets differing in their Ca contents (65 nmol cholecalciferol/kg diet) for 10 d and the activity of 25-HCC-1-hydroxylase in kidney homogenates, Ca absorption from the duodenum, Cabinding protein (CaBP) activity in the duodenal mucosa and plasma Ca and phosphate concentrations were all determined.3.The CaBP activity and the efficiency of Ca absorption both decreased with increasing dietary intake of Ca. Ca absorption and CaBP activity were significantly correlated (r 0.995, P < 0.01).4.The activity of 25-HCC-1-hydroxylase decreased as the dietary level of Ca increased and was significantly correlated with Ca absorption (r0.900, P < 005). The plasma Ca concentration and the activity of 25-HCC-1-hydroxylase were inversely related (r-0.940, P < 0.01).5.It is concluded that in the vitamin D-replete chick the efficiency of duodenal Ca absorption is regulated by the renal 25-HCC-1-hydroxylase activity via production of 1,25-dihydroxycholecalciferol and CaBP synthesis.

scholarly journals Combinations of cholecalciferol and 25-hydroxycholecalciferol as vitamin D sources in white laying hen feed diets

2014 ◽  
Vol 38 (6) ◽  
pp. 573-580
Author(s):  
Diego Fernando Remolina Rivera ◽  
Antonio Gilberto Bertechini ◽  
Tiago Ferreira Birro Oliveira ◽  
Solange de Faria Castro ◽  
Henrique Braga Oliveira ◽  
...  
Keyword(s):  
Vitamin D ◽  
Egg Production ◽  
Laying Hens ◽  
Egg Quality ◽  
Egg Laying ◽  
Available P ◽  
Egg Mass ◽  
Productive Performance ◽  
Positive Effects ◽  
25 Hydroxycholecalciferol

The effect of cholecalciferol (D3) and 25-hydroxycholecalciferol (25-OHD3) as isolated or associated sources of vitamin D (100%-0%, 75%-25%, 50%-50%, 25%-75%, 0%-100%) on the productive performance, egg quality, and bone characteristics was evaluated in white egg-laying hens fed two levels of calcium (Ca) and phosphorus (P) in the basal diet (BD) (BD1 = 0.38% Ca - 0.36% available P and BD2 = 3.2% Ca - 0.30% available P). Nine hundred and sixty Dekalb White hens (24 weeks old) were distributed into 80 cages, under a completely randomized factorial design for 16 weeks. The use of associated sources of vitamin D reduced the feed intake and feed conversion ratio, as well as BD1, which also increased the egg production and egg mass. The association of vitamin D sources with up to 50% 25-OHD3 increased the eggshell percentage. There was interaction (p<0.05) between the sources of vitamin D and the concentrations of Ca and available P, sources with at least 50% 25-OHD3 increased ash percentage and bone radiographic densitometry (BRD) with BD1; in BD2 the use of 25-OHD3 as isolated vitamin D source increased BRD. The association of D3 and 25-OHD3 improved the productive performance, increased the percentage of eggshell and had different positive effects on the bone characteristics that depend on the concentrations of Ca and available P in the balanced feed of white egg-laying hens.

Feedback Regulation of 25-Hydroxycholecalciferol Metabolism by Vitamin D3

1975 ◽  
Vol 48 (3) ◽  
pp. 227-230
Author(s):  
I. M. A. Evans ◽  
K. W. Colston ◽  
L. Galante ◽  
I. MacIntyre
Keyword(s):  
Vitamin D ◽  
Vitamin D3 ◽  
Actinomycin D ◽  
Feedback Regulation ◽  
Kidney Cells ◽  
Hydroxylase Activity ◽  
25 Hydroxycholecalciferol

1. In vitamin D-deficient chicks both vitamin D3 and 1α-hydroxycholecalciferol markedly decrease renal 1-hydroxylase activity and induce 24-hydroxylase activity. 2. Actinomycin D abolishes both effects. 3. These results are consistent with feedback regulation of vitamin D3 metabolism by a direct nuclear action of the vitamin or its metabolites on the kidney cells.

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