Cimini V, Van Noorden S, Timson C M, Polak J M
Department of Histochemistry, Royal Postgraduate Medical School, London, UK.
Cell Tissue Res. 1993 Apr;272(1):137-46. doi: 10.1007/BF00323579.
The localization of galanin in rat lactotropes and human corticotropes is well established. Neuromedin U immunoreactivity is present in rat corticotropes but radioimmunoassay of thyroid-manipulated rat pituitaries has also linked it to the thyroid axis. We found galanin immunoreactivity in some rat corticotropes, so we have re-examined rat anterior pituitary galanin- and neuromedin U-like immunoreactivity by use of immunocytochemistry and electron microscopy in rats in the normal state and after estrogen administration or adrenalectomy. In normal rats galanin immunoreactivity was present in a few corticotropes and lactotropes, females showing more than males; neuromedin U-like immunoreactivity was present in some thyrotropes and most corticotropes, in both sexes. Where galanin, neuromedin U and ACTH immunoreactivities were colocalized in corticotropes they were present in the same granules. Estrogen administration caused an increase in number of galanin immunoreactive lactotropes, as previously shown. The proportion of neuromedin U-positive corticotropes was not affected. After adrenalectomy, only females showed a significant increase in the proportion of galanin-positive corticotropes. Neuromedin U immunoreactivity was significantly increased in both sexes, as previously shown. Thus, in rat, as in man, galanin can be present in corticotropes and its expression appears to be sex-related. This finding, and the demonstration of thyrotrope neuromedin U (only examined in normal females), provide correlation with previous experiments. The influence of endocrine status on the expression of these novel peptides underlines the inherent plasticity of pituitary endocrine cells.
甘丙肽在大鼠促乳素细胞和人促肾上腺皮质激素细胞中的定位已得到充分证实。神经降压素U免疫反应性存在于大鼠促肾上腺皮质激素细胞中，但对甲状腺功能受调控的大鼠垂体进行放射免疫分析也将其与甲状腺轴联系起来。我们在一些大鼠促肾上腺皮质激素细胞中发现了甘丙肽免疫反应性，因此我们利用免疫细胞化学和电子显微镜，重新检查了正常状态下以及给予雌激素或进行肾上腺切除术后大鼠垂体前叶中甘丙肽和神经降压素U样免疫反应性。在正常大鼠中，少数促肾上腺皮质激素细胞和促乳素细胞存在甘丙肽免疫反应性，雌性大鼠中的数量多于雄性；神经降压素U样免疫反应性存在于一些促甲状腺激素细胞和大多数促肾上腺皮质激素细胞中，两性均有。在促肾上腺皮质激素细胞中，甘丙肽、神经降压素U和促肾上腺皮质激素免疫反应性共定位时，它们存在于相同的颗粒中。如先前所示，给予雌激素会导致甘丙肽免疫反应性促乳素细胞数量增加。神经降压素U阳性促肾上腺皮质激素细胞的比例未受影响。肾上腺切除术后，只有雌性大鼠中甘丙肽阳性促肾上腺皮质激素细胞的比例显著增加。如先前所示，两性的神经降压素U免疫反应性均显著增加。因此，在大鼠中，与人一样，促肾上腺皮质激素细胞中可存在甘丙肽，其表达似乎与性别相关。这一发现以及促甲状腺激素细胞中神经降压素U的证实（仅在正常雌性中进行检查），与先前的实验结果相关。内分泌状态对这些新肽表达的影响突显了垂体内分泌细胞固有的可塑性。
