Interleukin-6 secreting human pituitary adenomas in vitro.

Interleukin-6 was found to be secreted from seven out of ten human pituitary tumours cultured in vitro. These tumours included prolactin-secreting, growth hormone-secreting and clinically non-functioning adenomas. The amount of Interleukin-6 secreted was variable from 58 to 10,000 units per ml. in medium removed after a four-day incubation under basal conditions. Four tumours secreted IL-6 in excess of 500U/ml, three of which were clinically non-functioning, but each secreted follicle stimulating hormone in vitro. This is the first report of a cytokine growth factor being released basally by human pituitary tumours.