Interleukin-8 production from human somatotroph adenoma cells is stimulated by interleukin-1β and inhibited by growth hormone releasing hormone and somatostatin

Objective: Pituitary adenomas cause morbidity and mortality due to their localization and influence on pituitary hormone secretion. Although the pathogenesis of pituitary adenomas is unclear, studies have indicated that cytokines are involved. We investigated the role of cytokines, in particular interleukin (IL)-8, in the pathogenesis of growth hormone (GH) producing tumours. Design: Human somatotroph adenoma tissue was obtained from patients undergoing surgery for acromegaly. The tissue underwent mechanical and enzymatic digestion, was washed, suspended and cultured in 24-chamber plates. After stimulation/inhibition supernatants were harvested. As control of growth hormone producing properties of the cultured cells, GH releasing hormone (GHRH) stimulated and somatostatin inhibited the GH response. Results: The cultured adenoma cells released both IL-6 and IL-8 and the secretion was inhibited by GHRH and somatostatin. IL-1 beta dose-dependently stimulated GH, IL-6 and IL-8 secretion. Conclusion: Using cultured primary somatotroph adenoma cells as a dynamic method, we found a consistent release not only of IL-6 as described previously, but also of IL-8. This finding could be important for reassessing a role of these cytokines in the pathogenesis of pituitary tumour growth and function, and thus form a basis for targeted therapy. In line with previous studies, our results further indicated a common physiological or pathophysiological reaction of endocrine cells to cytokine stimulation. (C) 2011 Growth Hormone Research Society. Published by Elsevier Ltd. All rights reserved.