Lee E R, Leblond C P
Am J Anat. 1985 Mar;172(3):205-24. doi: 10.1002/aja.1001720304.
The isthmus of typical mucous units of the pyloric antrum was investigated in 3- to 4-month-old CD1 mice using light and electron microscopy as well as 3H-thymidine radioautography. On the average, the isthmus measured 25 microns in length and was composed of 36 isthmal cells and two enteroendocrine cells. Isthmal cells generally displayed features found in embryonic cells, such as many free ribosomes, scant organelles, and a large reticulated nucleolus, and were, therefore, at an immature stage of development. Isthmal cells could be devoid of secretory granules ("granule-free cells," 2%) or contain a few small, spherical, PA-Schiff-positive, mucous granules in their apex. The granules in some of the cells had a variegated appearance and a diameter averaging 235 nm ("mottled granule cells," 39%); in other cells, the granules had a large diameter, 278 nm, with a pale background and a dense core ("core granule cells," 28%); while in still others they were homogeneously dark and measured 264 nm ("dense granule cells," 12%). Finally, some cells included a mixture of core and dense granules ("mixed granule cells," 14%). One hour after a single injection of 3H-thymidine, 37% of the isthmal cells were labeled. Each of the five isthmal cell types could acquire label and, therefore, divide. After one or more days of continuous 3H-thymidine infusion, all isthmal cells were labeled. Their turnover time was estimated to be 16.1 hr (t1/2 = 11.2 hr). The isthmus is thus composed of several cell types which are turning over rapidly. While all are relatively immature, the various types are thought to represent different developmental stages in the life history of an isthmal cell. A model devised on this basis proposes that the granule-free cells are stem cells, from which mottled granule cells are derived. These in turn evolve into either the dense granule cells of the upper isthmus or the core granule cells of the lower isthmus, or into the mixed granule cells (which are believed to develop eventually into dense granule cells or core granule cells). Maintenance of a steady state requires that the rapid production of isthmal cells be associated with rapid emigration; the dense granule cells presumably going to the pit and the core granule cells to the gland. The turnover of isthmal cells is accordingly described as following a "bidirectional pattern" of renewal.
利用光学显微镜、电子显微镜以及3H-胸腺嘧啶放射自显影技术，对3至4月龄CD1小鼠幽门窦典型黏液单位的峡部进行了研究。峡部平均长度为25微米，由36个峡部细胞和两个肠内分泌细胞组成。峡部细胞通常呈现出胚胎细胞的特征，如许多游离核糖体、细胞器稀少以及有一个大的网状核仁，因此处于发育的不成熟阶段。峡部细胞可能没有分泌颗粒（“无颗粒细胞”，占2%），或者在其顶端含有一些小的、球形的、PA-希夫染色阳性的黏液颗粒。一些细胞中的颗粒呈现出斑驳的外观，平均直径为235纳米（“斑驳颗粒细胞”，占39%）；在其他细胞中，颗粒直径较大，为278纳米，背景较淡且有致密的核心（“核心颗粒细胞”，占28%）；而在另外一些细胞中，颗粒均匀地深染，直径为264纳米（“致密颗粒细胞”，占12%）。最后，一些细胞包含核心颗粒和致密颗粒的混合物（“混合颗粒细胞”，占14%）。单次注射3H-胸腺嘧啶1小时后，37%的峡部细胞被标记。五种峡部细胞类型中的每一种都可以获得标记，因此都能分裂。在连续输注3H-胸腺嘧啶一天或多天后，所有峡部细胞都被标记。它们的更新时间估计为16.1小时（半衰期 = 11.2小时）。因此，峡部由几种快速更新的细胞类型组成。虽然所有细胞都相对不成熟，但不同类型的细胞被认为代表了峡部细胞生命历程中的不同发育阶段。在此基础上设计的一个模型提出，无颗粒细胞是干细胞，斑驳颗粒细胞由其衍生而来。这些斑驳颗粒细胞进而演变为峡部上部的致密颗粒细胞或峡部下部的核心颗粒细胞，或者演变为混合颗粒细胞（据信最终会发育成致密颗粒细胞或核心颗粒细胞）。维持稳态要求峡部细胞的快速产生与快速迁移相关联；致密颗粒细胞大概会迁移到胃小凹，而核心颗粒细胞会迁移到腺体。因此，峡部细胞的更新被描述为遵循一种“双向模式”。
