The currently accepted remission criteria of acromegaly are mean 24-hour GH levels < 2.5 μg/l (ng/ml) (5 mU/l) or GH nadir after oral glucose tolerance test (OGTT) < 1 μg/l (ng/ml) (2 mU/l) in the presence of age, gender, and assay-specific normal IGF-I levels [5,10-13]. Here, IGF1 is linked to acromegaly.