Saland L C, Samora A, Desai S
Department of Anatomy, University of New Mexico School of Medicine, Albuquerque 87131.
Anat Rec. 1990 May;227(1):97-103. doi: 10.1002/ar.1092270111.
The pituitary intermediate lobe, a source of pro-opiomelanocortin (POMC) peptides, was examined with light and electron microscopic techniques in Sprague-Dawley rats aged 5-18 months and Zucker rats aged 18 months. Cysts were common in the intermediate lobe in the Zucker animals, a finding also noted in human pituitary glands by other investigations. The nuclear envelopes were often indented in cells of aging rats, while those of young animals were generally smooth. Lipid droplets and lysosomes, rarely seen in tissue from young animals, were frequently observed in endocrine cells of older rats. Most cells had an abundance of secretory granules, suggestive of enhanced storage of peptides in the cytoplasm. Nerve terminals which were present among endocrine cells contained myelin figures in some of the old rats, and may indicate degenerative changes, while other terminals appeared normal. These morphologic findings suggest that the aging phenomena in intermediate lobe tissue have characteristics in common with nervous tissue, and may also reflect a diminished inhibitory neuroregulation.
采用光镜和电镜技术，对5至18月龄的Sprague-Dawley大鼠以及18月龄的Zucker大鼠的垂体中间叶（促肾上腺皮质激素原（POMC）肽的来源）进行了检查。囊肿在Zucker动物的中间叶中很常见，其他研究在人类垂体中也发现了这一现象。老龄大鼠细胞的核膜常呈凹陷状，而幼龄动物的核膜通常是光滑的。脂滴和溶酶体在幼龄动物组织中很少见，但在老龄大鼠的内分泌细胞中经常观察到。大多数细胞含有丰富的分泌颗粒，提示细胞质中肽的储存增加。内分泌细胞之间存在的神经末梢在一些老龄大鼠中含有髓鞘样结构，这可能表明存在退行性变化，而其他末梢看起来正常。这些形态学发现表明，中间叶组织中的衰老现象与神经组织有共同特征，也可能反映出抑制性神经调节减弱。
