Growth hormone induced rise in glomerular filtration rate is not obliterated by angiotensin-converting enzyme inhibitors

Abstract

In 8 healthy normotensive probands with normal glomerular filtration rate, the effect of recombinant human growth hormone (rhGH) on inulin clearance (Cin) was examined in an open study with intraindividual crossover with or without enalapril pretreatment (20 mg/day). rhGH was administered by subcutaneous injection (4.5 U twice daly) for 3 days. On the following day Cin was measured with an enzymatic steady state infusion technique. Systemic hemodynamics and potential metabolic effects of rhGH, i.e., inulin-like growth factors I and II, somatomedin-binding protein, glucagon, C peptide, amino acid pattern, etc., were monitored. On controlled dietary intake of protein, the median Cin rose 72 h after start of rhGh administration from 114 (range 91-158) to 135 (108-167) ml/min/1.73 m2 without enalapril pretreatment (p less than 0.01) and from 111 (88-153) to 131 (100-173 ml/min/1.73 m2 with enalapril pretreatment (p less than 0.02). The results confirm that (1) rhGH increases Cin to a similar extent as extractive GH and (2) further demonstrate that this action is not obliterated by blocking the circulating converting enzyme.