Urinary growth hormone measurements in children with renal insufficiency.

Abstract

It has been reported that intrinsic renal factors could affect urinary growth hormone (UGH) measurements. We compared UGH excretion in 21 children aged 4-16 years, with various degrees of renal insufficiency, with that in 10 control subjects aged 5-13 years. We found 100- to 1000-fold elevations in UGH in children with plasma creatinine concentrations > 120 mumol/L (Group A) compared with patients with plasma creatinine concentrations < 120 mumol/L (Group B) and control subjects. UGH excretion (microU) in the three groups was as follows: group A 804-8556 (median 2649); group B 1.0-85 (median 7.5); and controls 2.6-7.3 (median 4.0). Elevated urinary beta 2-microglobulin levels (microgram) were also observed in group A patients: 875-15,400 (median 11,637) as compared with group B, 1.0-104 (median 32) and controls, 3-18.7 (median 8.0). There was no significant difference in albumin excretion between groups A and B through six patients in group B with nephrotic syndrome (NS) excreted significantly more albumin (P < 0.05) than the other 15 patients investigated. Our data show that abnormalities of renal function have a profound effect on growth hormone excretion and we suggest proximal tubular dysfunction as the causative factor. We conclude that UGH measurements do not provide a reliable means of assessment of hypothalamo-pituitary function in patients with renal insufficiency.