Detecting And Locating Of Melatonin Receptor In Thyroid Of Human Embryo And Its Molecular Characteristics

As one of the important. ueuro-endocrinology hormone, melatonin was usually thinked of as a hormone which mainly regulate the physiology rhythm in living body. With the proceeding of melatonin study these years, it has been found gradually that melatonin can also regulate the function of reproductive system, immune system and have effect of antioxidation and antitumor. Because of the importance of all these function and the characteristic of small molecular, hydrophobic and wide-existing, melatonin and its further function is being paid more and more attention to by many scientists and laboratories. With so much important function founded, the target organ of melatonin has not been cleared far away yet now. So the study of the active mechanism of melatonin was obstructed and the study of the act site has become one of the important works in the melatonin field. It has been reported that melatonin can regulate the thyroid function and influence the level of thyroid hormone. Therefore, in order to make the active mechanism clear, study of the problem that whether there exist melatonin receptors in thyroid and what the types they are is very necessary. In this study, using several study technics and methods we managed to resolve some questions as these: 1. Are there melatonin receptors in the thyroid organ? 2. Did the melatonin receptors locate in the thyroid cells? 3. Which position do the receptors exist in the cell? 4. How about the quantity of the melatonin receptors? The final destination is to supply some new data for the study of the mechanism how the melatonin regulate the thyroid function. Main mathods and results: 1. Extract total RNA from thyroid and hypothalamus. Amplify with the primer of MT1 and MT2 receptor respectively. -4- Electrophorese and sequeuce the amplify product. Result: electrophoresis sbowpositive result of the RT-PCR with either MT1 or MT2 receptor primer in boththyroid and bypothalamus. Sequencing result show that the DNA sequence ofproduction ere coincidc with the sequencc frOm GENE BANK. The resultindicate that there express MTl and MT2 receptors in thyroid organ. Comparedwith positive control, the quantity of the tWo Idnd of receptor is smaIIerrespcctively 2. SIice up the thyroid and hypothalamus organs and detected themelatonin rcceptor with immunohistochemistry method. The result show that inthc slice, pretreated with the antibody of MTl or MT2 recepton brown granulesdeposited in the mcmbrane, cytosol and nucIear of the thyroid cell orhypothalamus cell. 3. After extracting totaI RNA frOm thyroid andhypothaIamus, electrophorese and transmember in RNAase-free environmentand dyeing them with MTl and MT2 probe. The result show that, no matterwith the MTl or MT2 probe, the plasma of the thyroid cell or hypothaIamus ceIlare all positively dyed. The quantity of MTl and MT2 in thyroid are all Iess thanthose in hypothalamus.Conclusion: Thyroid celI of human embryos express two Idnds of melatoninreceptors, MTl and MT2. They located in the membrane, cytosoI and nuclearof thyroid cells. The quantity of MTl is smaIIer comparcd with that in thehypothalamus and no difference in that of MT2. Thesc indicate that the thyroidof human cmbryo is one target organ of meIatonin. It can act on the thyroiddirectly to rcgulate the thyroid function or the development of the thyroid ofhuman embryo.