Dopaminergic regulation of the biosynthetic activity of individual melanotropes in the rat pituitary intermediate lobe: a morphometric analysis by light and electron microscopy and in situ hybridization.
Dopaminergic regulation of the biosynthetic activity of individual melanotropes in the rat pituitary intermediate lobe: a morphometric analysis by light and electron microscopy and in situ hybridization.
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大鼠垂体中间叶中单个黑素细胞生物合成活性的多巴胺能调节：通过光学和电子显微镜以及原位杂交进行形态测量分析。
DOI：
10.1210/endo-123-4-1992
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发表时间：
1988
期刊：
影响因子：
4.8
通讯作者：
William R. Millington
中科院分区：
文献类型：
--
作者：
B. Chronwall;Gregory R. Hook;William R. Millington
大鼠垂体中间叶（IL）的原代细胞类型为多角形分泌细胞，核为光滑卵圆形。然而，本研究的结果表明，IL促黑素细胞是一个异质性细胞群体。黑素细胞的细胞质的着色特性不同，一些细胞出现明显的黑暗，其他人更轻，和细胞染色在中间shades也发现。电子显微镜形态测定显示，深色染色的黑素细胞有一个更致密的胞质溶胶，含有更多的粗面内质网，线粒体和分泌小泡比轻细胞。此外，原位杂交研究，使用POMC探针，表明POMC mRNA分布不均匀的黑素细胞之间的模式相媲美的分布的光明和黑暗的细胞。这些研究进一步表明，多巴胺能药物治疗，这是已知的改变POMC相关的肽从IL的分泌，产生平行的变化，在组织学染色性能和POMC mRNA的量/细胞。氟哌啶醇治疗显着增加了黑暗的黑素细胞的数量和POMC mRNA的量在每个细胞中，并消除了染色性能和POMC mRNA的分布的细胞异质性。溴隐亭治疗后，光促黑素细胞的数量增加，每个细胞含有降低水平的POMC mRNA。这些发现表明，个别促黑素细胞保持不同水平的生物合成活性，并且改变POMC肽的分泌的处理影响个别促黑素细胞中POMC合成的速率和IL的细胞异质性。
The primary cell type of the intermediate lobe (IL) of the rat pituitary is a polyhedral secretory cell with a smooth ovoid nucleus. The results of this study demonstrate, however, that IL melanotropes are a heterogeneous cell population. Melanotropes differed in the tinctorial properties of their cytoplasm; some cells appeared distinctly darker, others lighter, and cells staining in intermediate shades were also found. Electron microscopical morphometry revealed that darkly staining melanotropes have a denser cytosol and contain a greater amount of rough endoplasmic reticulum, mitochondria, and secretory vesicles than light cells. In addition, in situ hybridization studies, using a POMC probe, showed that POMC mRNA was distributed unevenly among melanotropes in a pattern comparable to the distribution of light and dark cells. These studies further demonstrated that dopaminergic drug treatments, which are known to alter the secretion of POMC-related peptides from the IL, produced parallel changes in both the histological staining properties and the amount of POMC mRNA per cell. Haloperidol treatment dramatically increased the number of dark melanotropes and the amount of POMC mRNA in each cell and eliminated the cellular heterogeneity in both staining properties and the distribution of POMC mRNA. After bromocriptine treatment the number of light melanotropes increased, and each cell contained reduced levels of POMC mRNA. These findings indicate that individual melanotropes maintain different levels of biosynthetic activity and that treatments that alter the secretion of POMC peptides affect both the rate of POMC synthesis in individual melanotropes and the cellular heterogeneity of the IL.