垂体前叶内神经纤维可能参与ACTH分泌的调节

我们建立了垂体组织块短时温育并施加电场刺激的离体实验体系，运用此方法并结合放射免疫测定激素含量，观察了大鼠垂体前叶内神经纤维对促肾上腺皮质激素（ＡＣＴＨ）释放的影响。结果表明，电场刺激能够促使垂体前叶ＡＣＴＨ释放显著增加，刺激参数为强度３０ｍＡ，波宽０．５ｍｓ，频率１０Ｈｚ。这个效应可为温育液中加入河豚毒素（ＴＴＸ）和藜芦碱所阻断，但ＴＴＸ不能阻断精氨酸加压素（ＡＶＰ）诱发的ＡＣＴＨ分泌。同样参数的电场刺激对分散培养的大鼠垂体前叶细胞ＡＣＴＨ的分泌没有显著作用。以上结果说明，我们所用参数的电场刺激产生的效应是兴奋了垂体前叶内的神经纤维，而非直接刺激腺细胞所致。上述结果提示：垂体前叶激素分泌的调节除了传统的体液途径之外，还可能存在直接的神经控制。

INVOLVEMENT OF THE NERVE FIBER ELEMENTS IN THE ANTERIOR PITUITARY IN THE REGULATION OF ACTH SECRETION

While peptidergic nerve fibers have been immunoreactively identified in the adenohypophysis of mammals, the function of these fibers in the regulation of hormone secretion remain unknown. The present work was undertaken to investigate possible modulatiug effects of these fibers on the secretion of ACTH in the anterior pituitury. Electrical field stimulation (EFS) was applied to excite the nerve terminals in anterior pituitary quarters of male rats under static incubation, and the ACTH level was determined by radioimmunoassay. It was found that the ACTH release from the anterior pituitary was significantly enhanced by EFS (30 mA, 0. 5 ms and 10 Hz), which could be significantly decreased by adding TTX or veratridine into the incubation medium. However,TTX failed to inhibit AVP-induced ACTH secretion. Since the dispersed cultured anterior pituitary cells did not respond to the same EFS, it was suggested that there might exist dual modulatory mechanisms on the anterior pituitary hormone secretion.