title: Interleukin-1 beta enhances interleukin-1 receptor antagonist content in human somatotroph adenoma cell cultures.
abstract: In addition to the well-known modulation of immune and inflammatory responses, the interleukin-1 (IL-1) system has been shown to be involved in the regulation of anterior pituitary hormone secretion and growth. We previously demonstrated that IL-1 receptor antagonist (IL-1ra) is expressed in human pituitary adenomas cultured in vitro. In the present study, we investigated the regulation of IL-1ra protein by IL-1 beta (1-100 U/mL) in human somatotroph adenomas (n = 9) cultured for 12-48 h. IL-1 beta significantly enhanced the concentration of IL-1ra dose dependently in the somatotroph adenoma cell lysates, whereas IL-1ra concentrations remained unchanged in the culture supernatants. Furthermore, basal IL-1ra concentrations were significantly higher in the cell lysates compared with the corresponding culture supernatants. The regulation of IL-1ra in somatotroph adenoma cells is different from human cultured monocytes, in which IL-1 beta significantly stimulated IL-1ra secretion into the culture supernatants, and no change of intracellular IL-1ra content was observed. Incubation of the somatotroph adenoma cells with 100 U/mL IL-1 beta did not result in a change of GH concentrations in the culture supernatants. Enhancement of intracellular IL-1ra protein by IL-1 beta may represent a mechanism intrinsic to somatotroph adenoma cells to counterregulate the response to IL-1 beta on hormone secretion or cellular growth.
authors.affiliation: Max-Planck-Institute of Psychiatry, Department of Endocrinology, Munich, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Sauer
authors.forename: U
authors.initials: U
authors.lastname: Renner
authors.forename: U
authors.initials: U
authors.lastname: Hopfner
authors.forename: M
authors.initials: M
authors.lastname: Lange
authors.forename: A
authors.initials: A
authors.lastname: Müller
authors.forename: C J
authors.initials: CJ
authors.lastname: Strasburger
authors.forename: U
authors.initials: U
authors.lastname: Pagotto
authors.forename: E
authors.initials: E
authors.lastname: Arzt
authors.forename: G K
authors.initials: GK
authors.lastname: Stalla
mesh_terms: D000236:Adenoma / Q000188:drug therapy* / Q000378:metabolism; D000328:Adult; D000368:Aged; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D007375:Interleukin-1 / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D010911:Pituitary Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors*; D014407:Tumor Cells, Cultured
chemical_list: D007375:Interleukin-1; D017472:Receptors, Interleukin-1