Regulation and role of intrapituitary IL-6 production by folliculostellate cells.

Interleukin-6, mainly produced by monocytes and macrophages is known to influence the secretion of anterior pituitary hormones and is, therefore, considered to play an important role in the interaction between the immune system and the endocrine system. However, IL-6 represents not only a lymphocyte message but is also produced within the anterior pituitary. Folliculostellate (FS) cells have been identified as the source of the intrapituitary IL-6 production in the normal pituitary, whereas in pituitary adenomas IL-6 is produced by the tumor cells themselves. The present review summarizes the knowledge about the regulation of the intrapituitary IL-6 synthesis and release in FS cells. Moreover, the possible roles of the intrinsic IL-6 production for function and growth of normal and adenomatous endocrine pituitary cells are discussed.