Somatostatin Regulates Raw 264.7 Cell Cytokine Release

Immigrant monocytes and resident macrophages propagate the vertebrate innate immune response through cell migration and cytokine production. Monocytes responding to inflammatory challenge migrate into tissues, and as resident macrophages, release a major pro-inflammatory cytokine, tumor necrosis factor a (TNF-a). Macrophge cytokine synthesis is known to be under both negative and positive regulatory control. Recent studies have shown that somatostatin (SRIF) regulates monocyte and peritoneal macrophages. However, the effects of SRIF on RAW 264.7 cells, a transformed monocyte/macrophage cell line, have not been investigated. In the present study, SRIF effect on cytokine release in LPS stimulated RAW 264. 7 cells was examined. Somatostatin regulated monocyte response to LPS stimulation as reflected by decrease in TNF-a release. In particular, LPS showed temporal TNF-a release peaking at 2h. SRIF, 7 10 at physiological concentrations (10- M to 10- M) showed dose independent reduction 10 on TNF-a release. We found SRIF 10- M concentration inhibited TNF-a release to the 10 maximum at 2 h. Finally, we show SRIF 10- Mover a time course inhibited maximum TNF-a release at 2 h in LPS stimulated RAW 264.7 cells. Taken together, our results show that SRIF modulates TNF-a release in LPS stimulated RAW 264.7 cells