Effects Of Triiodothyronine On Neuropeptide Y Gene Expression In Zebrafish Embryos

Triiodothyronine(T3) is a hormone secreted from the thyroid gland, synthesising withtetraiodothyronine(T4) both in thyroglobulin molecules, with T4have the same life activity, butit played a much more strong effective than T4. T3receptor in the nucleus of the liver and otheraffects the process of metabolism of almost all tissues and organs. Learning and memoryfunction where mammals with damaged is related to the local neuron lack of T3. A certainamount of T3can reduce the vascular resistance, myocardial contraction and cardiac outputincreased in mammals. In addition, T3have a certain effect on embryonic skeletal, hematopoieticsystem, eyes, gene expression and feeding in zebrafish. Neuropeptide Y (NPY) is a polypeptidewhich play a very important role in inducing the vertebrate feeding. If T3concentrations on thegrowth and development is related to the expression of NPY in zebrafish.If T3may directlyaffect NPY and participate in the appetite mechanism of regulation,it is a very importantsignificance in feeding and growth in zebrafish.In the research, we observed the NPY genes clearly spatiotemporal expression of eachperiod by in situ hybridization in the zebrafish embryo,the result shows that in every period ofzebrafish embryo have obvious hybridization signals.12h later, it express many in the embryo’souter mantle. Along with the gradual growth of the embryos, its expression from the brainregions transferred to the digestive organs, bones and other areas. This study lays down thefoundation for further studies of the mechanisms of the process of embryonic developmentcontrolled by NPY genes in zebrafish.To explore the Influence of T3on the growth and ingestion of zebrafish，the embryonic ofzebrafish were cultured with different different concentration of T3.The result shows that theexpression of NPY is the hightest in group cultured with5nM of T3， this group also have thefastest growth rate. When the concentration of T3is more than5nM, the expression of NPY isless and the deformity and mortality rate are highter.Speculating that the NPY plays a a crucial role in the development of the brain, formationof the bone and ingestion of the embryonic of zebrafish. The5nM of T3can promote theexpression of NPY of the zebrafish. In a certain range, the expression of the NPY was negatively correlated with the concentration of T3. Speculating the T3affects the NPY and participates inthe regulation of appetite mechanism directly.