Vitamin D status regulates 25-hydroxyvitamin D3-1 alpha-hydroxylase and its responsiveness to parathyroid hormone in the chick.

Booth, Beverley E.; Tsai, Huan C.; Morris, R. Curtis

doi:10.1172/jci111668

Cited by 43 publications

(18 citation statements)

References 38 publications

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“…The renal synthesis of 1,25(OH)2D, the most biologically active metabolite of vitamin D, is catalyzed by 25-hydroxyvitamin D a-l-hydroxylase (1-hydroxylase)l (1)(2)(3)(4)(5)(6)(7), an enzyme that can be stimulated by PTH (8)(9)(10)(11)(12)(13)(14) and suppressed by 1,25(OH)2D (10,12,13,15), normal vitamin D status (14), blood ionized calcium (10,(16)(17)(18), and some function of the 1. Abbreviations used in this paper: l-hydroxylase, 25-hydroxyvitamin D a-l hydroxylase; PR, production rate; 25-OHD, 25-hydroxyvitamin D.…”

Section: Introductionmentioning

confidence: 99%

Physiologic regulation of the serum concentration of 1,25-dihydroxyvitamin D by phosphorus in normal men.

Portale¹,

Halloran²,

Morris³

1989

J. Clin. Invest.

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260

106

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We asked this question: in normal humans, is either a normal dietary intake or normal serum concentration of phosphorus a determinant of the serum concentration of 1,25(0H-)D? In seven normal men whose dietary phosphorus was decreased from 2,300 to 625 mg/d, each intake for 8-9 d, under strictly controlled, normal metabolic conditions, we measured serum concentrations of 1,25(OH)2D daily, and concentrations of phosphorus hourly throughout a 24-h period, before and after restriction. Decreasing dietary phosphorus induced: (a) a 58% increase in serum levels of 1,25(OH)2D; (b) a 35% decrease in serum levels of phosphorus measured in the afternoon; (c) a 12% decrease in the 24-h mean serum level of phosphorus; but, (d) no decrease in morning fasting levels of phosphorus. Serum concentrations of 1,25(OH)2D varied inversely and significantly with 24-h mean concentrations of phosphorus (r = -0.77, P < 0.001). When these data are combined with those of our prior study in which dietary phosphorus was varied over an extreme range, the relationship between serum levels of 1,25(OH)2D and 24-h mean serum levels of phosphorus is even stronger (r = -0.90, P < 0.001). In the aggregate, the results demonstrate that in normal men, dietary phosphorus throughout a normal range and beyond, can finely regulate the renal production and serum concentration of 1,25(OH)2D, and provide evidence that this regulation is mediated by fine modulation of the serum concentration of phosphorus.

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Section: Introductionmentioning

confidence: 99%

Physiologic regulation of the serum concentration of 1,25-dihydroxyvitamin D by phosphorus in normal men.

Portale¹,

Halloran²,

Morris³

1989

J. Clin. Invest.

Self Cite

260

106

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“…(OH)2D], the most biologically active metabolite of vitamin D known, is catalyzed by 25-hydroxyvitamin D-la-hydroxylase (1-hydroxylase) (1)(2)(3)(4)(5)(6)(7), an enzyme that can be stimulated by parathyroid hormone (PTH)' (8)(9)(10)(11)(12)(13)(14), and suppressed by 1,25-(OH)2D (10,12,13,15), normal vitamin D status (14), blood ionized calcium (10,(16)(17)(18), and some function of the dietary intake of inorganic phosphorus ( 19,20). When dietary phosphorus is restricted in normal adult subjects (21)(22)(23)(24)(25) and in patients with moderate renal insufficiency (26,27), the serum concentration of 1,2540H)2D increases.…”

Section: Introductionmentioning

confidence: 99%

Dietary intake of phosphorus modulates the circadian rhythm in serum concentration of phosphorus. Implications for the renal production of 1,25-dihydroxyvitamin D.

Portale¹,

Halloran²,

Morris³

1987

J. Clin. Invest.

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207

130

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IntroductionWe recently reported that in healthy men, changes in the production rate (PR) (29), the serum concentration of 1,2540H)2D decreases. We have shown in healthy men that these phosphorus-induced changes in serum concentration of 1,25-(OH)2D can be accounted for entirely by changes in the production rate (PR) of the hormone (25). The mechanism by which changes in dietary phosphorus induce changes in the PR of 1,25-(OH)2D has, however, not been defined. In the chick and rat, the concentration ofphosphorus in serum (1 1, 19, 30, 31) or bathing medium (32) can be an important determinant of the activity of l-hydroxylase and the production rate of 1,25-(OH)2D. Yet, in humans, both restriction (24) and supplementation (25, 28) of dietary phosphorus can induce sustained changes in serum concentration of 1,25-(OH)2D without sustained changes in the morning fasting serum concentration ofphosphorus. These observations raise the question of whether changes in serum concentration of phosphorus do in fact mediate the changes in serum concentration of 1 ,2540H)2D induced by manipulation of dietary phosphorus.In normal subjects ingesting a normal diet, the serum concentration of phosphorus exhibits a circadian rhythm that is characterized by a nadir in the morning, a rise in early afternoon, and a peak at night (33-37). Indeed, Stanbury reported such a circadian rhythm in serum phosphorus in normal adult subjects ingesting only a small, constant amount of fluid hourly for 24 h (33). But Jubiz et al. subsequently reported that the nocturnal peak in serum phosphorus level was abolished in normal subjects receiving neither food nor fluid for 24 h, and suggested that the circadian changes in serum phosphorus were due in large part to food ingestion (35). In fact, it is not known whether the circadian rhythm in serum phosphorus can be affected by changes only in phosphorus intake in sub-

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“…In vitamin D-replete chicks, both basal and PTH-stimulated renal la-hydroxylase activity are diminished (35). In contrast, basal and PTH-stimulated activities increase with deprivation of vitamin D, and basal renal 25-hydroxyvitamin D-la-hydroxylase varies inversely with serum 1,25(OH)2D (35). These findings provide evidence that 1,25(OH)2D modulates its own synthesis both in the basal state and in response to PTH.…”

Section: Regulation Of Vitamin D Metabolismmentioning

confidence: 72%

“…In the vitamin D-deficient state, renal synthesis of 1,25(OH)2D is maximal, and synthesis is inhibited by addition of 1,25(OH)2D (24,33,34). In vitamin D-replete chicks, both basal and PTH-stimulated renal la-hydroxylase activity are diminished (35). In contrast, basal and PTH-stimulated activities increase with deprivation of vitamin D, and basal renal 25-hydroxyvitamin D-la-hydroxylase varies inversely with serum 1,25(OH)2D (35).…”

Section: Regulation Of Vitamin D Metabolismmentioning

confidence: 99%

Vitamin D-endocrine system.

Bell¹

1985

J. Clin. Invest.

142

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Vitamin D status regulates 25-hydroxyvitamin D3-1 alpha-hydroxylase and its responsiveness to parathyroid hormone in the chick.

Cited by 43 publications

References 38 publications

Physiologic regulation of the serum concentration of 1,25-dihydroxyvitamin D by phosphorus in normal men.

Physiologic regulation of the serum concentration of 1,25-dihydroxyvitamin D by phosphorus in normal men.

Dietary intake of phosphorus modulates the circadian rhythm in serum concentration of phosphorus. Implications for the renal production of 1,25-dihydroxyvitamin D.

Vitamin D-endocrine system.

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