THE POSTNATAL-DEVELOPMENT OF THE RAT-KIDNEY, WITH SPECIAL REFERENCE TO THE CHEMODIFFERENTIATION OF THE PROXIMAL TUBULE
THE POSTNATAL-DEVELOPMENT OF THE RAT-KIDNEY, WITH SPECIAL REFERENCE TO THE CHEMODIFFERENTIATION OF THE PROXIMAL TUBULE
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DOI：
10.1007/bf00493025
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发表时间：
1981-01-01
期刊：
影响因子：
--
通讯作者：
KLEHN, KL
中科院分区：
文献类型：
--
作者：
NEISS, WF;KLEHN, KL
新生的肾单位原基在出生后第4天出现于肾皮质。最后形成的原基在PD 10时发育成功能性肾单位，并且在皮质形成后的PD 12时皮质似乎成熟。肾髓质由Henle袢和集合管的纵向生长发育而成。未成熟的髓质不能分为不同的区域，在结构上对应于外部区域的较晚的内部条纹。内部区域由PD 8形成，外部区域的外部条纹由PD 12形成。PD 21时肾髓质成熟。从发育开始，肾近端小管就由曲部和直部组成。在这两个部分中，刷状缘酶（碱性磷酸酶，γ-磷酸酶）的形成都是由细胞内的细胞壁形成的。谷氨酰转肽酶、二肽氨基肽酶IV）和溶酶体酶（酸性磷酸酶、酸性β-半乳糖苷酶、N-乙酰氨基葡糖苷酶、二肽氨基肽酶II）。在近端小管成熟的过程中，溶酶体酶活性在曲部下降（刷状缘酶活性恒定），而刷状缘酶活性在直部增加（溶酶体酶活性恒定）。这两个部分的进一步不同之处在于，它们从一开始就表现出不同的溶酶体模式，卷部含有大量大的、高酶活性的溶酶体，这些溶酶体成组排列，而直部对应于成熟的S3节段。曲部的S1和S2段首先在PD 10和PD 21之间区分，因为大溶酶体的组逐渐破碎并且溶酶体器的范围减小，这从未成熟的曲部的末端以逆行方向进行。
New nephron primordia appear in the renal cortex up to the 4th postnatal day (PD). The last primordia formed develop into functional nephrons by PD 10, and the cortex appears mature at PD 12 after formation of the cortices. The renal medulla develops by the longitudinal growth of the loop of Henle and collecting ducts. The immature medulla cannot be divided into different zones and corresponds structurally to the later inner stripe of the outer zone. The inner zone is formed by PD 8, and the outer stripe of the outer zone by PD 12. The renal medulla is mature at PD 21. From the start of its development, the renal proximal tubule consists of the pars convoluta and pars recta. In both parts the formation of the brush border enzymes (alkaline phosphatase, .gamma.-glutamyltranspeptidase, dipeptidylaminopeptidase IV) and lysosomal enzymes (acid phosphatase, acid .beta.-galactosidase, N-acetylglucosaminidase, dipeptidylaminopeptidase II) over the full length of the proximal tubule. During the course of proximal tubule maturation, the lysosomal enzyme activities decline in the pars convoluta (with constant brush border enzyme activities), while the brush border enzyme activities increase in the pars recta (with constant lysosomal enzyme activities). The 2 parts further differ in that they exhibit different lysosomal patterns from the outset, the pars convoluta containing numerous large, highly enzyme-active lysosomes arranged in groups, and the pars recta corresponds to that of the mature S3 segment. The S1 and S2 segments of the pars convoluta first differentiate between PD 10 and 21, as the groups of large lysosomes are progressively broken up and the extent of the lysosomal apparatus is diminished, this proceeding in a retrograde direction from the end of the immature pars convoluta.