In 38 recurrent calcareous nephrolithiasis patients (RCN) and in 17 normal fasting subjects we studied the effects of an oral-calcium load on urinary-excretion rate of zinc (ZnE, μg/100 ml GFR), which is credited to inhibit calcium phosphate crystal-formation in urine. There were no significant differences in plasma-zinc levels (P(Zn), μg/dl) and basal ZnE between normal subjects and RCN (P(Zn): 85 ± 16 and 86.6 ± 12.7; ZnE: 0.29 ± 0.21 and 0.4 ± 0.18, respectively); calcium load did not modify ZnE either in normal subjects or in RCN. However, basal urinary Zn/Ca ratio (μg/mg) was significantly lower in RCN (3.6 ± 2.1) than in normals (7.45 ± 6.1, p <0.02), and further fell after calcium load to 1.8 ± 1 in RCN and to 2.2 ± 1.6 in normal subjects (p <0.001 and <0.005, respectively). We suggest that a reduced Zn/Ca ratio may correspond to an increased risk for calcium-crystal precipitation in urine.
|Title of host publication||NUA International Journal of Nephrology Urology Andrology|
|Number of pages||4|
|Publication status||Published - 1980|
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