In vitro samples of primary cultures of somatotropinoma and rat pituitary adenoma cell line (GH3) showed that imatinib, a drug that causes growth failure in CML probably targeting GH or IGF-1 axis, inhibited GH secretion in a dose-independent manner and without affecting cell viability. This evidence concerns the gene GH1 and chronic myelogenous leukemia, BCR-ABL1 positive.