[Study on the activity of acromegaly: evaluation of IGF-I].

: The evaluation of acromegaly only with GH levels can be difficult. We have evaluated in 32 acromegalic patients the clinical activity and baseline GH after oral glucose and THR. IGF-I was also evaluated. According GH suppression by glucose, three groups were established. A) minimum GH less than ng/ml, B) minimum GH 2-5 ng/ml and C) GH less than 2 ng/ml. IGF-1 in group A was 8.8 +/- 4.1 U/ml (mean +/- SD) and in group C IGF-I was 1.4 +/- 0.5 U/ml. Group B presented heterogeneous clinic and IGF-I levels. A 4 years clinical and hormonal follow-up could be performed in 20 patients. Those patients who were clinically inactive maintained their GH levels less than 2 ng/ml, with normal IGF-I titers throughout the follow-up period. In summary, IGF-I is very reliable in the evaluation of acromegaly activity and only requires a baseline determination being thus very useful in initial screening. It also determines with great reliability the treatment effectiveness in the evolutive study.