BIOCHEMICAL MARKERS OF ACROMEGALIC ACTIVITY

Against a clinical score we compared the effectiveness of three bioche mical markers of acromegalic activity: a) growth hormone response to I V thyrotropin-releasing hormone, b) growth hormone suppression one hou r after an oral glucose load, c) basal plasma IGF-I levels. In 21 pati ents we obtained 39 observations comprising the four parameters. Accor ding to the clinical score, patients were divided into three groups: g roup I = patients before surgery; group II = improved but still clinic ally active; group III = clinically inactive. After IV thyrotropin-rel easing hormone, abnormal observations increased although the patients improved clinically, so that this test was excluded from statistical a nalysis. Abnormalities in plasma IGF-I levels and in GH suppression af ter oral glucose were similarly frequent in the groups studied: both 1 00% in group I, both 71.4% in group 11, 27.3% vs. 18.2% in group III ( p > 0.05). Both tests made exactly the same contribution to the other' s capacity to detect acromegalic activity: 3 out of 39 observations (5 .1%). We conclude that basal plasma IGF-I is the single best biochemic al marker to detect acromegalic activity, since it is statistically at least as useful as growth hormone suppression, and is far more simple for the patient and the laboratory.