DO SO-CALLED NORMAL GROWTH-HORMONE CONCENTRATIONS (2-5-MU-G L) INDICATE CURE IN ACROMEGALY/

The study was undertaken to determine whether acromegalic patients wit h mean growth hormone (GH) concentrations of 2 - 5 mu g/l have biochem ically active disease following pituitary surgery or radiotherapy. 22 patients with acromegaly, 22 post surgery, 19 post radiotherapy had GH concentrations estimated during: (i) an oral glucose tolerance test ( OGTT), (ii) a standard TRH test and (iii) 20 minute sampling for 8 hou rs. IGF-1 concentrations were measured. 6 normal subjects were also st udied. Patients were divided into 3 groups on the basis of their mean GH concentration during the 8 hour sampling, > 5 mu g/l, 2 - 5 mu g/l, <2 mu g/l. Patients with mean GH concentrations of 2 - 5 mu g/l (n = 6) had biochemically active disease: all had inadequate suppression of GH after OGTT, 5 had elevated IGF-1 concentrations, 4 had a paradoxic al response to TRH. Patients with mean GH concentrations > 5 mu g/l (n = 6) all had inadequate suppression after OGTT, 5 of 6 had increased IGF-1 concentrations, and 5 had abnormal responses to TRH. Of patients with mean GH concentrations < 2 mu g/l (n = 10), 2 had elevated IGF-1 levels, 5 had abnormal responses to TRH and 4 inadequate GH suppressi on after OGTT. GH pulse number was similar in the three groups and GH pulse amplitude was significantly higher in those with CH > 5 mu g/l c ompared to the other groups. In conclusion patients with GH concentrat ions of 2 - 5 mu g/l have biochemically active disease and should be c onsidered for further therapy after hypophysectomy.