Olbing H, Blaufox M D, Aschinberg L C, Silkalns G I, Bernstein J, Spitzer A, Edelmann C M
J Clin Invest. 1973 Nov;52(11):2885-95. doi: 10.1172/JCI107485.
The intrarenal distribution of radionuclide microspheres injected into the thoracic aorta was used to examine glomerular blood flow distribution (GBFD) in 26 healthy, unanesthetized puppies, ranging in age from 5 h to 42 days, and in 5 adult dogs. For analysis, the cortex was divided into four equally thick zones designated zone I (subcapsular) to zone IV (juxtamedullary). During the first 36 h of life, the highest flow rate was in zone II, which received 35.5+/-2.0%/g, compared with 26.8+/-1.4% to zone I, 23.7+/-1.4% to zone III, and 13.4+/-1.4% to zone IV. At age 6 wk, zone I had the highest rate of perfusion (48.6+/-2.1%, compared with 28.8+/-1.4% in zone II, 15.8+/-0.8%, in zone III, and 6.8+/-0.6% in zone IV). The 6-wk old animals resembled the adult animals, except for relatively greater perfusion per gram of zone I in the former group. Changes in relative GBFD did not correlate with those in arterial pressure or peripheral hematocrit. The distribution of glomeruli among the four zones of the cortex followed its own pattern of development. At birth and at 6 wk, the greatest density of glomeruli was in zone I (50.6+/-5.4 and 42.7+/-3.9%/g respectively, as compared with 24.1+/-2.9% in adults); in adults zone II contained the greatest density (39.1+/-1.6%). At birth the relative perfusion of glomeruli in zone I was only one-fifth that of glomeruli in zone IV, with intermediate values in zones II and III. By 6 wk of age, increased perfusion of the outer cortical glomeruli resulted in rates of flow in the four zones that did not differ significantly from each other. Relative perfusion in zone I continued to increase, so that in the adult animals perfusion in that zone was significantly greater than in the three deeper zones. These data demonstrate the marked hemodynamic changes that take place within the kidney during the first few weeks of life. The relatively greater blood flow of the most deeply situated nephrons in the early postnatal period suggests ascendancy of this population of nephrons and may have important functional implications.
将放射性核素微球注入胸主动脉，利用其在肾内的分布情况，对26只年龄在5小时至42天的健康未麻醉幼犬以及5只成年犬的肾小球血流分布（GBFD）进行了检测。为便于分析，将皮质分为四个厚度相等的区域，分别命名为区域I（被膜下）至区域IV（近髓质）。在出生后的前36小时内，血流速率最高的是区域II，该区域每克组织接受的血流量为35.5±2.0%，而区域I为26.8±1.4%，区域III为23.7±1.4%，区域IV为13.4±1.4%。在6周龄时，区域I的灌注速率最高（48.6±2.1%，而区域II为28.8±1.4%，区域III为15.8±0.8%，区域IV为6.8±0.6%）。6周龄的动物与成年动物相似，只是前一组中区域I每克组织的灌注相对较多。肾小球血流分布的相对变化与动脉血压或外周血细胞比容的变化无关。皮质四个区域内肾小球的分布遵循其自身的发育模式。出生时和6周龄时，肾小球密度最大的是区域I（分别为50.6±5.4和42.7±3.9%/克，而成人则为24.1±2.9%）；在成年动物中，区域II的密度最大（39.1±1.6%）。出生时，区域I中肾小球相对于区域IV中肾小球的灌注仅为五分之一，区域II和III中的灌注值介于两者之间。到6周龄时，皮质外层肾小球灌注增加，导致四个区域的血流速率彼此间差异不显著。区域I中的相对灌注持续增加，因此在成年动物中，该区域的灌注显著高于三个更深的区域。这些数据表明，在出生后的头几周内，肾脏内部发生了显著的血流动力学变化。出生后早期，位置最深的肾单位相对血流量较大，这表明该肾单位群体占优势，可能具有重要的功能意义。
