|Budget Amount *help
¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
Fiscal Year 2009: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2008: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2007: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Immune-endocrine interaction is thought to be important for fish health, especially following injury and inflammation. We investigated influences of growth hormone (GH) and insulin-like growth factor (IGF)-I, which are known not only as osmoregulatory but also immunomodulatory hormones, on the process of inflammation and expression of immune genes induced by administration of bacterial lipopolysaccharide (LPS). An intraperitoneal injection of LPS into rainbow trout increased expression of pro-inflammatory cytokine genes, tumor-necrosing factor (TNF)-α and interleukin (IL)-1, in peripheral blood leucocytes (PBL) and several tissues examined, suggesting provocation of inflammation. Following the peaks of expression of cytokine genes, IGF-I mRNA levels in PBL showed a significant increase by LPS injection. Administration of homologous IGF-I to rainbow trout increased TNF-αand IL-1 mRNA levels in gills, whereas those cytokine genes did not show significant change in other lymphoid tissues, head kidney or spleen. Administration of GH or IGF-I increased mRNA levels of Na^+,K^+-ATPase, beta-actin, cyclin, caspase, and lysozyme in gills. GH and IGF-I look the candidate of key-factor bridging among immune, endocrine, and osmoregulatory systems during adaptation to physical, osmotic, and disease stresses.