Kidney function in normal man during short-term growth hormone infusion

Kidney function was studied in 9 normal males before and during a 2 h growth hormone (GH) infusion of 50 ng/kg/min. The following variables were measured during each 20 min clearance period: glomerular filtration rate, GFR, effective renal plasma flow, RPF (steady state infusion technique with urinary collections using [125I]iothalamate and [131I]iodohippurate), and urinary albumin and beta2-microglobulin excretion rates (radioimmunoassays). The GH infusion resulted in a 10-fold increase in plasma GH concentration. All the above mentioned variables remained practically unchanged during the infusion except for a small (-5%) but significant decrease in renal plasma flow (P less than 0.01). Our negative results contrast to the findings of increased GFR and RPF during prolonged GH administration and suggest that GH requires several hours or days for its renal effects to become manifest.