The Function Of Insulin Like Growth Factor And Epidermal Growth Fator In Grass Carp Pituitary

Insulin-like growth factor(IGF)and epidermal growth factor(EGF)are widely distributed in various parts of the tissues,which play an important role in the organism.IGF could combine with IGFBP to regulate the physiological functions.Most of the IGF form of IGF/IGFBP complexes in the body,and only a few exist in free form.At present,the functions of IGF and EGF are mainly focused on the liver and gonadal tissues in the teleost,but their specific functions in the pituitary gland are still unclear.Based on this,using grass carp as the research modal to systematically explain the functions of IGF1/IGFBP1 a and EGF in the pituitary gland of teleost.The specific results are as follows:1.IGF1/IGFBP1 a is involved in regulating the expression of LH and FSH in grass carp pituitary.Firstly,we cloned the sequences of grass carp IGFs(IGF1,IGF2 a,IGF2b,IGF3)and IGFBP1(IGFBP1a,IGFBP1b).The sequence alignment results showed that the IGFs ligand family of grass carp was highly conserved.The mammalian and grass carp IGFBP1 a was highly conserved in the C-terminal and N-terminal regions,but not in the connecting domain.The results of tissue expression analysis showed that IGFBP1 a was highly expressed in grass carp pituitary,kidney and spleen.Using immunohistochemistry to further locate the specific distribution position of IGFBP1 a in the grass carp pituitary,The results show that IGFBP1 a is widely distributed in the neuropituitary area in the posterior pituitary gland,which indicated that IGFBP1 a may play an important function in the pituitary.Based on this,IGF1 and IGFBP1 a were used to treat grass carp pituitary primary culture cells,respectively.The results showed that IGF1 and IGFBP1 a could induce the 786 and 616 differential expression genes in grass carp pituitary,respectively.These differential expression genes are mainly involved in critical physiological functions such as cell growth,development,and immune response.Then,Next,using the primary cultured grass carp pituitary cells as the research object.Further studies found that IGF1 could induce the expression of LHβ and FSHβ in a time and dose-dependent manner,while IGFBP1 a could inhibit the expression of LHβ and FSHβ in a time and dose-dependent manner.Interestingly,co-treatment with IGF1 and IGFBP1 a in pituitary cells,the results showed that IGFBP1 a could block the induction of LHβ and FSHβ by IGF1.And IGFBP1 a could significantly inhibit the phosphorylation activation level of ERK and AKT by IGF1.The above results indicated that the inhibitory effect of IGFBP1 a on the expression of pituitary LHβ and FSHβ is achieved by blocking the effect of endogenous IGF1.2.EGF could induce UTS1,EGR1 and MMP13 in grass carp pituitary.EGF is a6 k Da small molecule protein containing 53 amino acids.It plays an important role in cell proliferation,differentiation and follicle formation by binding to its receptor ErbBs.In mammals and fish,the research on the function of EGF mainly focuses on the breast and gonadal tissues.However,the function of EGF in pituitary is less studied.Based on this,using grass carp pituitary cells as a research model.First,the results of transcriptome analysis showed that EGF-induced pituitary differentially expressed genes are mainly enriched in metal ion binding,cancer-related pathways,and metabolism-related pathways.Secondly,further study confirmed that EGF could significantly induce the expression of UTS1,EGR1 and MMP13 m RNA in grass carp pituitary cells in a time-and dose-dependent manner.Next,post-receptor signaling pathway studies showed that EGF could induce the expression of UTS1 and EGR1 by binding to ErbB1 and ErbB2 receptors by activating the MEK/ERK and PI3K/AKT/m TOR pathways.While EGF mainly binds to ErbB1 receptors and activate the MEK/ERK signaling pathway to induce the expression of MMP13.