Benzonana G, Dreifuss J J, Gabbiani G
Cell Tissue Res. 1979 Aug 3;200(1):123-33. doi: 10.1007/BF00236892.
In view of the suggestion that actin-like proteins might be involved in the final steps leading to hormone secretion, the actin content of pituitary glands of adult rats was determined by sodium dodecylsulfate-polyacrylamide gel electrophoresis (for total actin), by the DNAse method (which measures predominantly monomeric actin) and by immunocytochemistry. The amount of actin present in the neural lobe, expressed per mg total protein, was found to be comparable to that of other neural tissues. In contrast, in the anterior lobe, the ratio was significantly lower. The intensity of immunofluorescent staining with anti-actin antibodies was higher in the neural lobe than in either anterior or intermediate lobes. The intensity and distribution of tubulin immunofluorescent staining with anti-tubulin antibodies resembled that of anti-actin antibodies. Thus, three independent methods point to an uneven distribution of actin in the subdivisions of the pituitary gland, although all these subdivisions are believed to secrete their hormones by exocytosis. These data suggest that the bulk of actin present in pituitary cells is unlikely to be involved only in exocytosis, but may be implicated also in the intracellular translocation of secretory products.
鉴于有观点认为肌动蛋白样蛋白可能参与导致激素分泌的最后步骤，采用十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳法（用于检测总肌动蛋白）、DNA酶法（主要检测单体肌动蛋白）以及免疫细胞化学方法，测定了成年大鼠垂体腺的肌动蛋白含量。发现神经叶中每毫克总蛋白所含的肌动蛋白量与其他神经组织相当。相比之下，前叶中的该比例则显著较低。抗肌动蛋白抗体免疫荧光染色的强度在神经叶中高于前叶和中叶。抗微管蛋白抗体的微管蛋白免疫荧光染色的强度和分布与抗肌动蛋白抗体相似。因此，尽管垂体腺的所有这些亚部分都被认为是通过胞吐作用分泌其激素的，但三种独立方法均表明肌动蛋白在垂体腺各亚部分中分布不均。这些数据表明，垂体细胞中存在的大量肌动蛋白不太可能仅参与胞吐作用，还可能与分泌产物的细胞内转运有关。
