Prevention of hypercalcemia-induced renal concentrating defect and tissue calcium accumulation.
Prevention of hypercalcemia-induced renal concentrating defect and tissue calcium accumulation.
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预防高钙血症引起的肾浓缩缺陷和组织钙积累。
DOI：
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发表时间：
1986
影响因子：
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通讯作者：
R. Schrier
中科院分区：
文献类型：
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作者：
D. Harris;P. Gabow;S. Linas;D. Rosendale;S. Guggenheim;R. Schrier
通过观察伴随的限磷效应，探讨了高钙血症浓缩缺陷的机制。大鼠分别饲喂正常磷饲粮、不含磷饲粮（1组）、含二氢快胆固醇饲粮（2组）和低磷饲粮（3组）。高钙血症在2组（12.1 +/- 0.6 mg/dl）和3组（11.8 +/- 0.4 mg/dl）中相当，但3组的血清磷酸盐低于2组（3.8 +/- 0.7 vs. 7.1 +/- 1.1 mg/dl, P < 0.005）。与1组（3,263 +/- 466 mosmol/kg H2O）或3组（3,332 +/- 515 mosmol/kg H2O）相比，2组大鼠在24 h失液后最大尿浓度下降（2,441 +/- 450 mosmol/kg H2O, P < 0.001）。2组大鼠仅出现多饮、多尿。2组（83.1 +/- 33.5 mg/24 h, P < 0.001）高于1组（47.0 +/- 26.1 mg/24 h）和3组（52.8 +/- 19.3 mg/24 h）， 2组髓质钙浓度（7.57 +/- 3.08 nmol/mg干wt）高于1组（5.04 +/- 1.37 nmol/mg干wt）和3组（5.32 +/- 0.98 nmol/mg干wt）。3组髓质总溶质浓度显著高于2组。因此，磷酸盐限制可以防止慢性高钙血症尿浓缩能力的缺陷，可能是通过减少小管吸收和组织钙的积累。
The mechanism of the concentrating defect of hypercalcemia is explored by examining the effect of concomitant phosphate restriction. Rats were pair fed a normal phosphorus diet, without (group 1) or with dihydrotachysterol (group 2), or a low-phosphorus diet (group 3). Hypercalcemia was comparable in groups 2 (12.1 +/- 0.6 mg/dl) and 3 (11.8 +/- 0.4 mg/dl), but serum phosphate was lower in group 3 than group 2 (3.8 +/- 0.7 vs. 7.1 +/- 1.1 mg/dl, P less than 0.005). Group 2 rats had impaired maximum urinary concentration after 24 h of fluid deprivation (2,441 +/- 450 mosmol/kg H2O, P less than 0.001) compared with group 1 (3,263 +/- 466 mosmol/kg H2O) or group 3 (3,332 +/- 515 mosmol/kg H2O) animals. Polydipsia and polyuria were found in group 2 rats only. Tubular calcium reabsorption was higher in group 2 (83.1 +/- 33.5 mg/24 h, P less than 0.001) than group 1 (47.0 +/- 26.1 mg/24 h) or group 3 (52.8 +/- 19.3 mg/24 h) animals, and medullary calcium concentration was higher in group 2 (7.57 +/- 3.08 nmol/mg dry wt, P less than 0.05) as compared to group 1 (5.04 +/- 1.37 nmol/mg dry wt) or group 3 (5.32 +/- 0.98 nmol/mg dry wt) rats. Total medullary solute concentration was significantly higher in group 3 than group 2 animals. Thus phosphate restriction prevents the defect of urinary concentrating ability of chronic hypercalcemia, probably by decreasing tubular uptake and tissue accumulation of calcium.