Plasma renin, aldosterone, and urinary prostaglandin E levels in children with hypocalcemia due to vitamin D deficiency rickets.

We investigated the effect of hypocalcemia on plasma renin, aldosterone, and urine PGE levels in children with vitamin D deficiency rickets (VDDR). In the study group, 25 patients with VDDR-induced hypocalcemia were treated with a single dose of 150,000-300,000 IU cholecalciferol and 50 mg/kg/day elemental Ca for 10 days. On any day between 21th and 30th days after the treatment, the patients' clinical, biochemical and radiologic findings were re-evaluated. The healthy children with the same sex and similar age as the study group comprised the control group. Plasma sodium (Na), potassium (K), calcium (Ca), phosphorus (P), alkaline phosphatase (ALP), parathyroid hormone (PTH), 25- hydroxy vitamin D (25OHD), renin, aldosterone; and urinary Ca, creatinine (Cr) and prostaglandin E (PGE) levels were measured in both the study (pre-treatment and post-treatment) and the control group. Plasma Ca, P, 25OHD and renin levels and urinary PGE/Cr ratio in the post-treatment group were significantly higher than those in the pre-treatment group while K, ALP, and PTH concentrations were significantly lower. Plasma ALP and PTH levels in pre-treatment group were significantly higher than in the control group while Ca, P, 25OHD, aldosterone and renin concentrations and urinary PGE/Cr ratio were significantly lower. Post-treatment plasma Ca level was significantly decreased in normal limits compared to the control group while other biochemical parameters were not different from the control group. Plasma Ca concentration was positively correlated with renin level and urinary PGE/Cr ratio. The findings suggest that hypocalcemia may inhibit the production of renin, aldosterone and PGE and a blunt aldosterone secretion may develop even after recovery from hypocalcemia.