Evaluation of activity in postoperative acromegalics--plasma growth hormone levels during oral glucose tolerance test, daytime blood sampling and urinary GH excretion.

Plasma growth hormone (GH) levels during oral glucose tolerance test (OGTT) and during the daytime (0900-1700 h) and urinary GH excretion were determined in 6 normal subjects and 10 patients with postoperative acromegaly by means of a highly sensitive enzyme immunoassay (EIA). Acromegalic patients were divided into two groups according to their GH responses during OGTT. In group I patients plasma GH was suppressed below 1.0 microgram/l as in normal subjects, whereas GH levels persisted above 1.0 microgram/l in group II patients. Plasma GH profiles during the daytime were characterized by low nadir GH levels in normal subjects (0.21 +/- 0.10 microgram/l and group I patients (0.38 +/- 0.10 microgram/l) when compared with those in group II patients (4.7 +/- 2.0 microgram/l). Nadir GH levels during the daytime coincided with those during OGTT. Urinary GH excretions in group I patients (median 12 ng/day, range 4.3-29 ng/day) were within normal limits (2.6-20 ng/day) and significantly lower than those in group II patients (median 40 ng/day, range 19-130 ng/day.) Determination of plasma GH levels during OGTT and urinary GH excretion by the highly sensitive enzyme immunoassay is useful in evaluating the activity of postoperative acromegaly.