Urinary growth hormone excretion in preterm neonates.

We measured urinary growth hormone (U-GH), beta 2-microglobulin (U-B2) and serum growth hormone (S-GH) in preterm neonates on days 1, 4, 7, 14 and 28 of age. U-GH as well as U-B2 were high, particularly in the more premature and sick neonates with respiratory failure requiring mechanical ventilation. U-GH showed significant positive correlations with U-B2 throughout the study but with S-GH only on day 7. Therefore, we conclude that in preterm neonates, U-GH mainly reflects the degree of renal proximal tubular function, which is determined by the degree of renal maturation of the subject and of tubular injury due to disease states such as respiratory failure.