Effects of dexamethasone (DXM) on serum levels of growth hormone (GH), insulin-like growth factor (IGF)-I and IGF binding proteins (IGFBP) in chickens

摘要

The present investigation was conducted to determine the effects of DXM on serum levels of GH, IGF-I and IGFBP in chickens. Male Whihte Leghorn chickens (6 weeks) were injected with DXM (20 #mu#g/100g B.W). The samples of blood and various organs (liver, kidney, spleen and brain) were obtained on.time after DXM injection. In serum, the glucose level was not changed until final sampling time (90 minutes) but GH and IGF-I levels were decreased at 30 and 60 minutes respectively. The IGF-I binding activity was increased at 60 minutes by DXM injection. In organ extracts, the IGF-I binding activity of kidney and spleen was incresed so as in serum but those of brain and liver were not changed by DXM injection. The 34 KDa IGFBP was detected in both serum and kidney extracts of control but not detected in both those of DXM injection, althogh detected newly novel IGFBPs smaller than 34 KDa. These results strongly suggest that DXM affects the GH-IGF_I axis and alters IGFBPs in serum, kidney and spleen.