Maleic acid-induced impaired conversion of 25(OH)D3 to 1,25(OH)2D3: Implications for Fanconi's syndrome

Brewer, Eileen D.; Tsai, Huan C.; Szeto, King-Seing; Morris, R. Curtis

doi:10.1038/ki.1977.109

Cited by 35 publications

(9 citation statements)

References 42 publications

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“…Indeed, 25-OHD, levels below 5 ¡.tg/1 were associated with low total and free l,25-(OH)2D, levels, whereas short-term therapy with 25-OHD, normalized all parameters [28]. An addi tional disturbance in renal tubular function, as has been reported in patients with the nephrotic syndrome and normal GFR [29][30][31], could theoretically also affect the renal 25-OHD,-la-hydroxylase activity but our data do not confirm such a posibility. Although Bikle et al [32] recently suggested that free l,25-(OH)2D, levels are not accurately predictable from total DBPand l,25-(OH)2D, levels, their direct measurements equally involve several manipulations which may disturb the equilibrium and reliability of the direct free hormone estimation.…”

Section: Discussionmentioning

confidence: 87%

Decreased Free 1,25-Dihydroxycholecalciferol Index in Patients with the Nephrotic Syndrome

Auwerx¹,

Keyser²,

Bouillon³

et al. 1986

Nephron

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The serum concentrations of calcium, phosphorus, parathyroid hormone, vitamin D₃ metabolites and their transport protein (DBP) were measured in 18 patients with the nephrotic syndrome (mean daily proteinuria 8.8 g). The glomerular filtration rate was normal in 13 patients while the remaining 5 had a mild degree of renal failure. The serum concentrations of total protein, albumin and DBP were significantly decreased in patients with the nephrotic syndrome. The serum calcium concentration was decreased but the calculated ionized calcium concentration remained normal. The serum concentrations of 25-hydroxycholecalciferol (5.3 ± 3.1 μg/l) and 1,25-dihydroxycholecalciferol [1,25-(OH)₂D₃ (20 ± 12 ng/l)] were significantly lower in patients with the nephrotic syndrome and normal glomerular filtration rates than in normal controls (14.4 ± 4 μg/l and 42 ± 13 ng/l, respectively). The free 1,25-(OH)₂D₃ index was also significantly below normal (0.9 ± 0.4 vs. 1.8 ± 0.4). Total and free 1,25-(OH)₂D₃ were still further reduced in patients with mild renal failure. The nephrotic syndrome thus results in mild vitamin D depletion with decreased free 1,25-(OH)₂D₃ concentrations but generally without secondary hyperparathyroidism.

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Section: Discussionmentioning

confidence: 87%

Decreased Free 1,25-Dihydroxycholecalciferol Index in Patients with the Nephrotic Syndrome

Auwerx¹,

Keyser²,

Bouillon³

et al. 1986

Nephron

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“…For example, in X-linked hypophosphatemia, in which the basic defect is a disorder in tubular phosphate transfer, Scriver et al [7] observed a relatively low concentration of 1,25(OH)2Da, but other results are divergent [8]. In experimental Fanconi's syndrome, recent studies suggest a decrease in l~-hydroxylase renal activity [9]. Moreover, in renal phosphate leak related to fibrous tumors a low 1,25(OH)2D3 serum concentration has been observed [10,11].…”

Section: Discussionmentioning

confidence: 96%

Nonosteomalacic osteopathy associated with chronic hypophosphatemia

et al. 1982

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We studied bone histomorphometry in 19 patients with chronic hypophosphatemia related to an idiopathic renal phosphate wasting and without histological osteomalacia. Nine patients had renal lithiasis (group 1), three had radiological osteoporosis (group 2), and seven had lumbar pain (group 3). In the whole group of 19 patients, serum phosphate levels were low (24.9 +/- 2.1 mg/l), calcium in blood was normal, calcium in urine was increased, and iPTH was low. Histomorphometric data showed decreased osteoblastic surfaces with normal resorption surfaces, normal osteoid volume and calcification front. There was no correlation between serum phosphate level and histomorphometric parameters. There was no statistical difference between the data of the 3 groups of hypophosphatemic patients. We concluded that chronic hypophosphatemia in the adult doses not always lead to osteomalacia but to an unusual osteopathy characterized by an osteopenia due to an isolated decrease in bone formation. The respective importance of phosphate deficiency and of decreased iPTH level in the pathogenesis of this osteopathy is uncertain.

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“…Our usual clearance study procedures were carried out [1]. Each rat received 6 nil isotonic sodium chloride intravenously for 1 h to insure adequate hydration so that urine output was l-2m !/h.…”

Section: Methodsmentioning

confidence: 99%

“…Rats were awake, but restrained atop an inverted wire basket during the 3 h of study. In 4 rats with JVC+CAC, inulin clearance was measured as previously described [1] by administration of inulin, 7.5g/dl, in the control solution during the hour immediately after the isotonic saline was given and again 22 h later, just prior to sacrif icing the rats. Urine samples from spontaneous voidings were also tested with standard dipsticks (Labstix®, Ames) for glucose, blood, and protein.…”

Section: Methodsmentioning

confidence: 99%

“…Carotid arterial catheters (CAC), threaded retrograde toward the aorta, are used by some investigators [1][2][3] for the pur pose of repetitive sampling of arterial blood during clearance studies in rats. When this technique was used for studying the renal effects of maleic acid administration in awake animals, renal infarcts were observed in control as well as experimental animals.…”

Section: Introductionmentioning

confidence: 99%

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The Association of Renal Infarcts with Carotid Artery Catheters Used for Clearance Studies

Verani¹,

Brewer²,

Ince³

et al. 1982

Kidney Blood Press Res

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Maleic acid-induced impaired conversion of 25(OH)D3 to 1,25(OH)2D3: Implications for Fanconi's syndrome

Cited by 35 publications

References 42 publications

Decreased Free 1,25-Dihydroxycholecalciferol Index in Patients with the Nephrotic Syndrome

Decreased Free 1,25-Dihydroxycholecalciferol Index in Patients with the Nephrotic Syndrome

Nonosteomalacic osteopathy associated with chronic hypophosphatemia

The Association of Renal Infarcts with Carotid Artery Catheters Used for Clearance Studies

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