Bovine Adrenal Cells Secrete Interleukin-6 and Tumor Necrosis Factor in Vitro

Abstract

Interleukin-6 (IL-6) and tumor necrosis factor (TNF) are secreted and/or synthesized by the rat and human adrenal cortex. In this study, the release of IL-6 and TNF from bovine adrenal cells was determined. Bovine adrenal glandswere collected from an abattoir and dissected into the zona glomerulosa (ZG), zona fasciculata(ZF), zona reticularis (ZR), and medulla. The tissues wereenzymatically dispersed to single cells and culturedfor 4–6 days. The cells were then exposed (4 h) to angiotensin II (AII), adrenocorticotrophic hormone (ACTH), phorbol dibutyrate (PDB), interleukin-1β (IL-1β), interleukin-1α (IL-1α), and endotoxin (LPS). The IL-6 and TNF content of the incubation medium was determined by bioassays. The release of IL-6 and TNF from the ZG, ZF, ZR, and medulla was increased by PDB, IL-1α, IL-1β, and LPS. In contrast, ACTH and AII increased IL-6 release from the ZG, ZF, and ZR but had no effect on IL-6 release from the medulla. ACTH decreased TNF release from all adrenal cortical zones but had no effect on TNF release from the medulla. Immunohistochemistry utilizing antibodies against TNFα demonstrated TNFα-containing cells throughout the adrenal gland. The majority of the cells of the ZG, ZF, and ZR contained TNFα. However, the cells of the ZG contained more TNFα than the cells of the ZR or ZF. Small patches of TNFα-containing cells were also found in the adrenal medulla and capsule. These findings support the hypothesis that IL-6 and TNF may have autocrine/paracrine effects on the adrenal gland.