The metabolic clearance rate, serum half-time and apparent distribution space of authentic biosynthetic human growth hormone in growth hormone-deficient patients.

We studied the metabolic clearance rate (MCR) serum half-time (t1/2) and apparent distribution space (DS) of unlabelled, authentic, biosynthetic human growth hormone (B-hGH) in 9 GH-deficient patients by means of the constant iv infusion to equilibrium technique. B-hGH was infused for 3 h at a rate of 33 ng.kg-1.min-1 after which the disappearance from serum of GH was followed for 1 h. The mean +/- SEM values for MCR, t1/2 and DS were: 2.3 +/- 0.6 ml.kg-1.min-1, 21.1 +/- 1.7 min and 67.6 +/- 14.6 ml/kg, respectively. The disappearance of GH was monoexponential for the first 30 min, during which 75% of the GH had been cleared. The disappearance rate during the last 30 min of the observation period was somewhat lower, still approximately 90% of the GH had been eliminated after 60 min.