|Budget Amount *help
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1997: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1996: ¥1,000,000 (Direct Cost: ¥1,000,000)
Recently, we found that cytokine-induced neutrophil chemoattractant (CING), a key chemotactic factor in the immune system of the rat, was produced in the hypothalamo- pituitary system, and also influenced anterior pituitary hormone release. In addition, we previously reported that CINC is produced in the rat pituitary gland. The source of CINC has not yet been determined, but we speculate that folliculo-stellate (FS) cells are one of the candidates for CINC-producing cells in the pituitary. We investigated the possibility' of detection CINC immunoreactivity in the pituitary FS- like cell line (TtT/ GF). Intense immunoreactivity was observed by immunocytochemistry in the cytoplasm and cell processes of TtT/ GF cells. CINC immunoreactivity was detected by an enzyme- linked immunosorbent assay A as little as 3 h after conditioning the medium with TtT/ GF cells, and it increased significantly in a time- dependent manner during the first 24 h of the culture. This immunoreactivity could be induced by lipopolysaccharide (LPS) and tumor necrosis factor-a (TNF) in a time- and dose-dependent manner. We also observed the expression of CINO mRNA in TtT/ GF cells and LPS increased CINO mRNA accumulation in TtT/GF cells. Moreover, the mechanism of CINO secretion induced by LPS or TNF was investigated. Mitogen activated protein (MAP) kinase is knwon to be induced by various extra- stimuli. Therefore, the effect of LPS or TNF on MAP kinase was examined in TtT/GF cells. Both LPS and TNF induced MAP kinase activity. The treatment of MEK inhibitor, PD98059, which is a specific blocker of MAP kinase cascade, attenuated both LPS- and TNF- induced CINO secretion. These findings indicate that CINO produced by FS cells through MAP kinase cascade may play a role as paracrine factor of the pituitary gland.