The Regulation And Mechanism Of Melatonin On Progesterone Secretion In Porcine Corpus Luteum Cell

Melatonin is a neuroendocrine hormone that is produced by the changes in circadian rhythms that are produced by the secretion of the mammalian pineal gland and the retina.Studies have shown that Melatonin is mainly through its membrane receptor(Melatonin receptor,MR)play a role of biology,1998 IU PHAR meeting named mammalian receptors MT1 and MT2 and MT3 three subtypes.Melatonin in the hypothalamus and pituitary level regulating animal reproductive activities by the attention of the researchers,in recent years,studies have found that the target organs of ovarian also direct role of melatonin,melatonin receptor in ovary tissue widely distributed,the follicle development,estrogen and progesterone secretion has a regulation,but more concentrated in these studies and mouse,less research on livestock,especially of melatonin on livestock pregnancy corpus luteum function adjust action research is not reported.This study intends to choose pregnancy sow as the research object,using immunohistochemical staining,cell indirect immunofluorescence,QRT-PCR and western blotting methods such as research of melatonin receptor during pregnancy pig corpus luteum tissue and in vitro culture of corpus luteum cells distributed positioning,melatonin for pig corpus luteum cells progesterone secretion regulation of the function and mechanism.The results are as follows.1.The results of the immunohistochemical stain indicate that MT1 and MT2 are widely distributed in the gestation period,which is mainly in the corpus luteum cells.2.The indirect immunofluorescence of cells indicates that MT1 and MT2 are widely distributed in vitro cultured pig corpus luteum cells.The experimental results showed that the physiological concentration of melatonin(p<0.05)was significantly increased.3.Different concentration gradient of melatonin treatment corpus luteum cells for 24 h,the results showed that 1 pg/mL,5 pg/mL,25 pg/mL,125 pg/mL and 625 pg/mL of melatonin can significantly promote the secretion of progesterone(p<0.05),and a dose dependent.With 25 pg/mL and 125 pg/mL of melatonin treatment luteal cell 0 h,8 h,16 h,24 h,32 h,40 h and 48 h results show that progesterone secretion and processing time show dependencies,and training all the time after 8 h point of progesterone secretion were significantly higher than control group(p<0.05).With 25 pg/mL and 125 pg/mL melatonin treatment corpus luteum cells for 24 h,at the same time with melatonin receptor inhibitor treatment corpus luteum cells,the results found that melatonin on progesterone secretion,promote the corpus luteum cells was completely blocked.4.The effects of melatonin in the process of progesterone synthesis were measured by 25 pg/mL and 125 pg/mL melatonin,and the QRT-PCR and western blotting methods.The results showed that melatonin increased the expression of StAR and P450 scc,while the expression of 3β-HSD had no effect.Membrane receptor inhibitors block the increased role of melatonin in the expression of StAR and P450 scc.This study confirmed that the melatonin receptor MT1 and MT2 widely distributed in pregnancy pig corpus luteum organization,mainly located in the corpus luteum cells,physiological concentration of melatonin can significantly increase luteal cell activity.The study found that the release of melatonin through its membrane receptor MT1 and MT2 promoted the secretion of progesterone,and the timing and dose dependence of progesterone.Further studies have found that the role of melatonin in promoting the production of progesterone through MT1 and MT2 may be done by raising the StAR and P450 scc.