Horster M, Kemler B J, Valtin H
J Clin Invest. 1971 Apr;50(4):796-800. doi: 10.1172/JCI106550.
Morphometric analysis was carried out on kidneys of neonatal dogs in which function of the entire kidney and of single nephrons had been evaluated. Measurements were begun after neogenesis of nephrons had been completed, i.e., at the end of the 3rd postnatal wk. They were continued to 74 days by which time glomerular function, expressed per unit of renal weight, had reached the mature level. For statistical analysis, the cortical histogram at each age was divided into eight zones of equal depth between the capsule and corticomedullary junction. The mean total number of glomeruli in this beagle strain was 589 x 10(3) per kidney. The fraction of the total number of glomeruli was lowest in the subcapsular layer (3.9%) and highest (24.5%) in the zone immediately beneath from where it decreased almost linearly to a value of 4.5% in the juxtamedullary region. This numerical distribution did not change with age, which suggests that growth of nonglomerular structures proceeded at the same rate in all cortical layers. Volume of the glomerular tuft rose slightly between the subcapsular and next layer and remained constant down to the juxtamedullary region where it increased sharply. The juxtamedullary glomerulus was about 45% larger in volume than the other glomeruli. This intracortical distribution of glomerular volume did not vary between 23 and 74 days, although the volume of an individual glomerulus at each level increased slightly with age. Total glomerular volume increased by 33% during the postnatal period studied, whereas simultaneously nonglomerular cortical volume rose by 235%. On the assumption that nonglomerular tissue consists mainly of tubules, the data suggest that the rate of tubular growth far exceeded that of glomerular growth. Despite this difference in glomerular and tubular growth rates, analysis of single nephrons in these dogs demonstrates constant and mature proximal fractional reabsorption of sodium and water.
对新生犬的肾脏进行了形态计量分析，这些新生犬的整个肾脏和单个肾单位的功能已被评估。测量在肾单位新生完成后开始，即出生后第3周结束时。测量持续到74天，此时以单位肾重表示的肾小球功能已达到成熟水平。为了进行统计分析，将每个年龄的皮质直方图在被膜和皮质髓质交界处之间划分为八个深度相等的区域。在这个比格犬品系中，每个肾脏肾小球的平均总数为589×10³个。肾小球总数的比例在被膜下区域最低（3.9%），在紧挨着的下一层区域最高（24.5%），从该区域开始几乎呈线性下降，在近髓区域降至4.5%。这种数值分布不随年龄变化，这表明非肾小球结构在所有皮质层中的生长速度相同。肾小球丛的体积在被膜下和下一层之间略有增加，在近髓区域之前保持恒定，在该区域急剧增加。近髓肾小球的体积比其他肾小球大约大45%。肾小球体积的这种皮质内分布在23天至74天之间没有变化，尽管每个水平的单个肾小球体积随年龄略有增加。在所研究的出生后时期，肾小球总体积增加了33%，而与此同时，非肾小球皮质体积增加了235%。假设非肾小球组织主要由肾小管组成，这些数据表明肾小管的生长速度远远超过肾小球的生长速度。尽管肾小球和肾小管的生长速度存在差异，但对这些犬的单个肾单位进行分析表明，钠和水的近端分数重吸收是恒定且成熟的。
