GH1 and acromegaly: In patients with acromegaly, the average basal plasma GH and IGF-I levels were 1.40 ± 1.10 ng/mL (normal reference range, 0.05–10.0 ng/mL) and 253.0 ± 219.10 ng/mL (normal reference range, 169–591 ng/mL), respectively.