Expression Of Vesicular Glutamate Transporter I In Rat Anterior Pituitary

VGLUTs (vesicular glutamate transporters) are located at the vesicle membranes and provide the vesicles with relatively high concentration of glutamate. They may form glutamatergic system in these endocrine cells and regulate the secretory activity. Three types of VGLUTs with similar pharmacological characters have been discovered: VGLUT1,VGLUT2 and VGLUT3. In our study we demonstrated that VGLUT1 expressed in anterior pituitary in SD rats and have a relatively high colocalization percentage with ACTH.The results of our experiments were as following: Under the light microscope, VGLUT1 mainly located in the rostral or caudal area of the anterior pituitary, the expression in the central region is much weaker. VGLUT1 cells were found in the cell plasma membrane vesicles of ACTH cells and they were small, irregular-shaped, and polygonal. Immunohistochemistry study showed that VGLUT1 expressions in anterior pituitary were increased from low to high level and finally down to the normal level in young rats born after 1 day to 30 days (P < 0.01) with the changes of colocalization percentages of VGLUT1 and ACTH were consistent with it round above 75 % (P < 0.01). For the further study we explored the changes of VGLUT1 expression level after adrenalectomy (ADX) and found that: in the anterior pituitary of adult male SD rats the expression of VGLUT1 decreased at 7 days after ADX compared with normal controls and increased to the normal level then went higher at 14 days after ADX (P < 0.01). The real-time PCR has confirmed the result with significant changes (P < 0.01).In this study, immunohistochemistry combined with molecular biology techniques were used to explore the VGLUT1 distribution in the anterior pituitary of SD rat and to reveal the interaction mechanism of the glutamatergic system and the neuroendocrine system in rats at different developmental stages and under different endocrine status. It is to provide a new theoretical basis for exploring the mechanism of endocrine-related diseases.