Effects Of Low-concentration TPT On The Growth And GH/IGF-I Axis In Common Carp(cyprinus Carpio)

Triphenyltin?TPT?,as a typical organic pollution,has been widely used as many kinds of commercial products such as antifouling paint,pesticide,and fungicide.It affected aquatic organisms survive and the health of human indeed.Actually,the development of fish mainly was depended on the regulation of GH/IGF-I axis.Because of widely distributed,easily feeding,satisfactory economic value,Common carp was used as a model vertebrate species.Then it was used as a widely organism in scientific studies on influence of endocrine disrupting chemicals.In order to countersign the effects of TPT on GH/IGF-I axis and explore the pollution mechanisms,common carp were exposed to 0.024?g/L,0.24?g/L,2.4?g/L TPT exposure groups and control group for 7days,21 days,48 days.And then morphological indices,digestive enzyme activities,hematological parameters and the expression of genes related GH/IGF-I axis were analyzed.The results were showed that:1.Compared with control group,after 7 days exposure,HSI and CF of TPT exposure groups were not significantly changed.There was no significant change in HSI exposed to TPT for 21 days,however,CF was obviously decreased at 0.024?g/L,0.24?g/L TPT exposure groups.After 48 days exposure,HSI was showed significant increase at 2.4?g/L TPT exposure groups.At the same times,CF was significantly reduced at 0.24?g/L TPT exposure groups.2.The activities of lipase and trypsin located in intestine of common carp were expressed a weakly decreasing tendency after 7 days exposure of TPT.While after 21days and/or 48 days,the activities of lipase and trypsin were decreased significantly at TPT concentration increasing,showing evident dose-effect relationship.3.When exposed to 7 days,the levels of plasmic GH were showed significant increase at 0.24?g/Land 2.4?g/L TPT exposure groups,but the levels of IGF-I,E₂ and T of plasma were caused inhibited evidently.After long term exposure of TPT,the content of plasmic GH and IGF-I were declined at high TPT concentration.Nevertheless,the expression of E₂ and T of plasma did not have obvious change.4.Exposed to 7 days,the concentration of GH mRNA,GnRH mRNA of pituitary and GHR mRNA,IGF-IR mRNA in liver were increased.But hepatic IGF-I mRNA and IGFBP mRNA were inhibited at TPT exposure.While after 21 days,the expression of hepatic GHR mRNA,IGF-IR mRNA,IGF-I mRNA and pituitary GH mRNA were declined with TPT concentration increasing,and then hepatic IGFBP-1 mRNA level was obviously increased.There was a positive relationship between hepatic GHR mRNA,IGF-IR mRNA,IGF-I mRNA,IGFBP-1 mRNA level as well as pituitary GH mRNA level and TPT concentration exposed to 48days,while pituitary GnRH mRNA level was not showed significant change.