Urea synthesis, nitrogen balance, and glucose turnover in growth-hormone-deficient children before and after growth...

We measured the effect of human growth hormone (hGH) on urea synthesis, nitrogen retention, and glucose turnover in ten euthyroid growth hormone (GH)-deficient children before and after seven daily injections of 0.1 U/kg hGH. The patients were fed a weight-maintaining diet with 9% of energy derived from protein. Following an overnight fast, urea synthesis and glucose turnover were determined using a primed constant infusion of [15N2] urea and a constant infusion of [6,6-2H2] glucose. Human growth hormone produced a decrease in urea nitrogen synthesis from 6.8 +/- 0.5 to 4.2 +/- 0.4 mg/kg.h; (P less than .01), while plasma urea nitrogen decreased from 13.1 +/- 0.8 to 7.4 +/- 0.8 mg/dL; (P less than .01). The decrease in urea synthesis was reflected in a corresponding decrease in urine urea nitrogen excretion (-2.8 mg/kg.h). There was a significant correlation between plasma urea nitrogen and urea synthesis rate both before (r = 0.85, P less than .01) and after (r = 0.79, P less than .01) hGH treatment. In response to hGH, there was a rise in both plasma glucose (81.4 +/- 2.2 v 89.8 +/- 2.3 mg/dL; P less than .05) and insulin (5.7 +/- 0.8 v 13.1 +/- 3.0 microU/mL; P less than .05), however, glucose turnover remained unchanged (4.7 +/- 0.3 v 4.6 +/- 0.6 mg/kg.min). After seven days of growth hormone treatment, the patients were placed on 0.1 U/kg of hGH three times a week for 6 months, and their growth rate was calculated.(ABSTRACT TRUNCATED AT 250 WORDS)