Kerr J B, Weiss M
Department of Anatomy, Monash University, Clayton, Melbourne, Victoria, Australia.
Am J Anat. 1991 Feb;190(2):101-17. doi: 10.1002/aja.1001900202.
The cytology and ultrastructure of the hypertrophied special zone, which is formed spontaneously in the adrenal cortex of adult female brush-tailed possums (Trichosurus vulpecula), was compared to the adrenocortical tissue in adult males in which the special zone, normally absent, was induced following castration alone or by additional treatment with follicle-stimulating hormone (FSH). The special zone in females was situated between the zona fasciculata and the zona reticularis, the latter being a rudimentary zone in this species. Special zone tissue extended as a broad band parallel to and on one side of the adrenal medulla. In the luteal phase of the reproductive cycle, the special zone cells showed ultrastructural features commonly associated with steroidogenic tissues, with many mitochondria and compact masses of smooth endoplasmic reticulum. Cytoplasmic lipid inclusions were rarely observed. In lactating females, however, the special zone cells exhibited cytological and ultrastructural features suggestive of a transformation in their morphology broadly divided into two types of cells: (1) cells at the periphery of the special zone (closest to the zona fasciculata) showed variable quantities of lipid inclusions, mitochondria with dispersed cristae, and segregation of the smooth endoplasmic reticulum into compact masses; (2) cells within the more central regions showed an increasing abundance of lipid inclusions which in many cells became the dominant feature of the cytoplasm. These special zone cells contained very little smooth endoplasmic reticulum and their mitochondria contained few cristae together with amorphous granular material within the matrix. In castrated males, special zone tissue developed between the zona fasciculata and the zona reticularis, appearing initially as focal islands of cells (8 months postcastration) and later (11 months postcastration) expanding into a single zone, probably via the proliferation and differentiation of adjacent cells of the zona fasciculata and longitudinal growth of the special zone. Similar focal aggregations of special zone cells were induced after 14 days of FSH treatment given to 2-month castrated males. In all castrated and FSH-treated castrated males, the ultrastructure of special zone cells was similar to that of special zone cells in luteal-phase female possums. The findings suggest that the formation and cellular composition of the special zone is associated with changes in the pituitary-gonadal axis and that FSH plays a primary role in the differentiation of this tissue.
在成年雌性帚尾袋貂（Trichosurus vulpecula）肾上腺皮质中自发形成的肥大特殊带的细胞学和超微结构，与成年雄性肾上腺皮质组织进行了比较。在成年雄性中，单独阉割或额外用促卵泡激素（FSH）处理后可诱导出通常不存在的特殊带。雌性的特殊带位于束状带和网状带之间，在该物种中网状带是一个发育不全的带。特殊带组织呈宽带状，与肾上腺髓质平行并位于其一侧。在生殖周期的黄体期，特殊带细胞呈现出通常与类固醇生成组织相关的超微结构特征，有许多线粒体和紧密排列的滑面内质网。很少观察到细胞质脂质包涵体。然而，在哺乳期雌性中，特殊带细胞呈现出细胞学和超微结构特征，表明其形态发生了转变，大致分为两种类型的细胞：（1）特殊带周边（最靠近束状带）的细胞显示出数量不等的脂质包涵体、嵴分散的线粒体以及滑面内质网聚集成紧密的团块；（2）更中心区域的细胞显示脂质包涵体数量增加，在许多细胞中成为细胞质的主要特征。这些特殊带细胞含有很少的滑面内质网，其线粒体含有很少的嵴，基质内还有无定形颗粒物质。在阉割的雄性中，特殊带组织在束状带和网状带之间发育，最初表现为细胞的局灶性岛状结构（阉割后8个月），后来（阉割后11个月）可能通过束状带相邻细胞的增殖和分化以及特殊带的纵向生长扩展为单个带。对2个月龄阉割雄性给予14天FSH处理后，也诱导出了类似的特殊带细胞局灶性聚集。在所有阉割和FSH处理的阉割雄性中，特殊带细胞的超微结构与黄体期雌性袋貂特殊带细胞的超微结构相似。这些发现表明，特殊带的形成和细胞组成与垂体 - 性腺轴的变化有关，并且FSH在该组织的分化中起主要作用。
