Evaluation of acromegaly by measurement of 24-hourly urinary growth hormone excretion

Twenty-four hourly urinary growth hormone excretion (24-h uGH) has been quantified using a combination of ultrafiltration and conventional immunoradiometric assay. Twenty-four hourly uGH was measured in 20 normal adults and in 42 patients with acromegaly (9 untreated, 28 treated but with above-normal IGF-I levels, and 5 treated and cured). The means and ranges were as follows: 3.7 (1-9) ng/24 h for normals and 160 (40-540), 66 (2-380) and 5.2 (4-8) ng/24 h for the three groups of acromegalic patients, respectively. Ten patients with pituitary adenomas without acromegaly had 24-h uGH within the normal range. Twenty-four hourly uGH therefore gives a clear differentiation between controls and untreated patients. Log-transformed values for subjects with acromegaly showed significant correlations between 24-h uGH and levels of IGF-I (r = 0.63, p < 0.01), fasting plasma GH (r = 0.92, p < 0.001) and plasma GH after glucose loading (r = 0.85, p < 0.001). Twenty-four hourly uGH was also determined in three acromegalic patients before and during SMS 201-995 therapy. Twenty-four hourly uGH reflected the corresponding changes in mean levels for hourly sampling over 12 h of plasma GH and IGF-I and in clinical signs after 3-6 months of therapy. The results of this study indicate that 24-h uGH is an accurate indicator of GH secretion in acromegalic patients and could therefore be used both in diagnosis and in monitoring the progress of therapy in these patients.