Effect of Munc13ª²1 on insulin secretion during pancreatic development in rats

    YUAN Qingª²Xin£¬LIU Chao£¬TENG Liª²Ping£¬LIU Cuiª²Ping£¬ZHOU Jinª²Yong£¬GUO Jing£¬CHENG Mei£¬DE Wei

    Department of Endocrinology, First Affiliated Hospital, Departª²ment of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing 210029, China

    ¡¾Abstract¡¿ AIM: To investigate the expression of Munc13ª²1 during various stages of embryonic pancreatic development in rats and define the effect of Munc13ª²1 on insulin secretion. METHODS: Pancreata of rat embryonic day 12.5 (E12.5), E15.5, E18.5, newª²born, 21 d after birth (P21) and adult rats were dissected under microscope respectively. In addition, the animal models of intrauterine growth retardation (IUGR) in rats were made by 50% calorie restriction in pregnant rats from gestational day 15 until term. After abstraction of totle RNA and protein, the techniques of RTª²PCR, realª²time PCR, Western blot and ELISA were used to study the expression of Munc13ª²1 and insulin secretion. RESULTS: The genes of insulin and Munc13ª²1 began to be expressed from E12.5 and E15.5 respectively and their expressions were increased as the fetus grew. The result of Western blot showed that the expression of Munc13ª²1 was low at E15.5 and E18.5 and increased later. Blood insulin level was detected at E18.5 and increased rapidly thereafter. The blood insulin level and the expression of Munc13ª²1 were reduced simultaneously in IUGR models compared with normal newborn rats. CONCLUSION: The expression of Munc13ª²1 is accordant to blood insulin level and plays an essential role in insulin exocytosis. ......