The Urinary Excretion of Ionized and Non-Ionized Calcium by Rats Treated with 1.25-Dihydroxycholecalciferol

Rc, Puche; Da, Caferra; Mc, Fernández; Me, Locatto

doi:10.1055/s-2007-1013505

Cited by 2 publications

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“…Experimental evidence supports the possible role of VDR in the regulation of tubular citrate handling. In fact, it has been observed that 1,25(OH) 2 D 3 directly influences the activity of enzymes involved in the intracellular metabolism of citrate and in the transmembrane transport system of dicarboxylate [27–32]. The rapid nongenomic effects and the intracellular metabolism of 1,25(OH) 2 D 3 are controlled by VDR which, in humans, is also expressed in the distal and proximal renal tubule cells [8, 9, 33, 34].…”

Section: Discussionmentioning

confidence: 99%

Association between vitamin D receptor gene polymorphisms and tubular citrate handling in calcium nephrolithiasis

Mossetti¹,

Vuotto²,

Rendina³

et al. 2003

Journal of Internal Medicine

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Objectives. Hypocitraturia is a risk factor for calcium nephrolithiasis. 1,25(OH) 2 D 3 influences renal citrate handling and enhances citraturia. The aim of this study was to evaluate the relationship between vitamin D receptor (VDR) allelic variant and urinary citrate excretion in recurrent stone formers (SF) patients. Design. Case-control study. Subjects. A total of 220 recurrent calcium oxalate SF patients and 114 healthy control (C) subjects were enrolled for this study. Subjects with urinary tract infections, hyperparathyroidism, cystinuria >70 lmol/24 h, gouty diathesis, renal tubular acidosis, renal failure, chronic diarrhoeal states, intake of thiazide diuretics, angiotensin-converting enzyme (ACE)-inhibitors, glucocorticoids or oestrogens were excluded. A standard constant diet was given for 7 days. The 24-h urinary citrate excretion and the active tubular reabsorption of filtered citrate (Rcit) were evaluated. Hypocitraturia was defined as a urinary citrate excretion lower than 1.7 mmol day )1 .Stone formers patients and C were genotyped for BsmI and TaqI VDR alleles. Contingency table chi-square tests were used to compare genotype frequencies in hypocitraturic SF patients, normocitraturic SF and C.Results. The prevalence of hypocitraturia in SF patients was 32.7% (72 of 200). Hypocitraturia in these patients resulted from excessive Rcit of a normal load of citrate. We found a different distribution (P < 0.05) of BsmI and TaqI VDR genotypes in hypocitraturic SF patients compared with normocitraturic SF and C. In particular, the prevalence of bb and TT VDR genotypes in hypocitraturic SF was significantly higher than in normocitraturic SF and C. Conclusions. These results point to a genetic association between BsmI and TaqI VDR polymorphisms and idiopathic hypocitraturia in calciumoxalate recurrent SF patients.

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Section: Discussionmentioning

confidence: 99%