[Renal function of cations excretion in children predisposed to essential hypertension].

We studied the renal function of cations excretion in 86 normal children, aged 4-6 years old. 24-hour urinary excretion of sodium, potassium, calcium, magnesium, copper and zinc were measured before and after acute oral salt loading. The result showed that urinary sodium levels were significantly lower (101.88 mmol/24 h, 126.58 mmol/24 h, respectively, P less than 0.01) in children with family history of essential hypertension than in those without family history after salt loading. This suggests that the children with family history may have hereditary functional defect in the excretion of sodium before developing hypertension. We also found the renal excretions of potassium, calcium and zinc showed difference between children with and without family history of essential hypertension.