Beard M E, Novikoff A B
J Cell Biol. 1969 Aug;42(2):501-18. doi: 10.1083/jcb.42.2.501.
The distribution of peroxisomes (microbodies) in the rat nephron was studied cytochemically, using glutaraldehyde- or formaldehyde-fixed tissue, by means of alpha-hydroxy acid oxidase activity in light microscopy or oxidation of 3,3'-diaminobenzidine (DAB) at pH 9 in both light and electron microscopy.The two cytochemical methods show peroxisomes to be nearly sperical particles found only in cells of the proximal convoluted tubule. Lysosomes were identified in the same or parallel sections, with beta-glycerophosphate or 5'-cytidylic acid as substrate. They are found in all cells of the nephron. These cytochemical methods visualize the two organelles for light microscopy; they also permit unequivocal differentiation of all kidney peroxisomes from lysosomes in electron micrographs. Peroxisomes are larger and more reactive in the cells of the pars descendens (P(3) segment) of the proximal convolution, located in the outer medulla and medullary rays, than in the cells of the pars convoluta (P(1) and P(2) segments), situated in the cortex. In contrast, lysosomes are much smaller in the P(3) segment and larger and more reactive in the P(1) and P(2) segments. In all cells of the proximal convolution, peroxisomes tend to be concentrated nearer the base of the cells than do lysosomes. Mitochondria in P(3) cells also show low levels of DAB oxidation at pH 6, in contrast to those in P(1) and P(2) cells. The possibility is discussed that P(3) cells possess an extramitochondrial means of oxidation in which peroxisome oxidases play an important role.
利用戊二醛或甲醛固定的组织，通过光镜下的α-羟酸氧化酶活性以及光镜和电镜下pH 9时3,3'-二氨基联苯胺（DAB）的氧化反应，对大鼠肾单位中过氧化物酶体（微体）的分布进行了细胞化学研究。这两种细胞化学方法显示，过氧化物酶体是仅存在于近端曲管细胞中的近似球形颗粒。在相同或平行切片中，以β-甘油磷酸或5'-胞苷酸为底物鉴定了溶酶体。它们存在于肾单位的所有细胞中。这些细胞化学方法可在光镜下观察到这两种细胞器；在电子显微镜照片中，它们还能明确区分所有肾过氧化物酶体和溶酶体。位于外髓和髓放线中的近端曲管降支（P(3)段）细胞中的过氧化物酶体，比位于皮质中的曲段（P(1)和P(2)段）细胞中的过氧化物酶体更大且反应性更强。相比之下，P(3)段中的溶酶体要小得多，而P(1)和P(2)段中的溶酶体更大且反应性更强。在近端曲管的所有细胞中，过氧化物酶体往往比溶酶体更集中于细胞底部附近。与P(1)和P(2)细胞中的线粒体相比，P(3)细胞中的线粒体在pH 6时也显示出较低水平的DAB氧化。文中讨论了P(3)细胞可能具有一种线粒体外氧化方式，其中过氧化物酶体氧化酶起重要作用。
