Permeability of renal peritubular capillaries to neutral dextrans dextrans and endogenous albumin

Deen, WM; Ueki, IF; Bm, Brenner

doi:10.1152/ajplegacy.1976.231.2.283

Cited by 40 publications

(14 citation statements)

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“…SNGFR increased in each animal (Fig. 1 ' Increase in CA has also been observed after isoncotic plasma infusion in previous studies (14,40). It is speculated that this increase in systemic plasma protein concentration reflects high intracapillary hydraulic pressure in peripheral capillary during plasma volume expansion, presumably causing extravasation of colloid-free fluid.…”

Section: Resultssupporting

confidence: 64%

Blood flow dependence of postglomerular fluid transfer and glomerulotubular balance.

Kon¹,

Hughes²,

Ichikawa³

1983

J. Clin. Invest.

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A B S T R A C T The rate of blood flow entering a capillary network can, in some vascular systems, regulate capillary surface area and the rate of fluid and solute transfer. To determine whether such a mechanism exists in the renal peritubular capillary, we performed micropuncture studies in 28 rats during relatively low and high efferent arteriolar blood flow (EABF). High EABF was achieved by intravenous infusion of isoncotic plasma (group 1: from 120±11 to 301±49 nl/min [±SE]); whole blood with high hematocrit (-75 vol %) (group 2: from 141±14 to 252±31 nl/min); or acetylcholine (group 3: from 193±20 to 266±26 nl/min). In group 1 rats, plasma infusion caused an increase in single nephron glomerular filtration rate (SNGFR), on average, from 23.2±2.4 to 45.2±3.9 nl/min, owing primarily to increased glomerular plasma flow rate (from 63±5 to 210±21 nl/min). The rate of fluid uptake by the peritubular capillary, assessed by the absolute rate of proximal fluid reabsorption (APR), also rose significantly, on average from 10.5±1.2 to 17.5±2.4 nl/min. This rise in APR was associated with near constancy in mean transcapillary hydraulic (AP() and oncotic (AlIc) pressure differences, and was therefore at-

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Section: Resultssupporting

confidence: 64%

Blood flow dependence of postglomerular fluid transfer and glomerulotubular balance.

Kon¹,

Hughes²,

Ichikawa³

1983

J. Clin. Invest.

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“…For renal lymph, a, = 1.89 and a2 = 0.469 (for 0 _ C _ 2 g/dl), assuming an A/G of 2.0, the ratio also found in rats by us and others (21,22 …”

Section: Calculationssupporting

confidence: 75%

“…where a, = 1.63 and a2 = 0.249 (for 4 _ C ' 10 g/dl) for plasmas, assuming an albumin-to-globulin concentration ratio (A/G) of 1.0, the ratio found in normal rats by us and others (20)(21)(22). For renal lymph, a, = 1.89 and a2 = 0.469 (for 0 _ C _ 2 g/dl), assuming an A/G of 2.0, the ratio also found in rats by us and others (21,22 …”

Section: Calculationsmentioning

confidence: 90%

Mechanism of Inhibition of Proximal Tubule Fluid Reabsorption after Exposure of the Rat Kidney to the Physical Effects of Expansion of Extracellular Fluid Volume

Ichikawa¹,

Brenner²

1979

J. Clin. Invest.

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A B S T R A C T The natriuresis and concomitant decline in absolute proximal reabsorption (APR) that occur in rats in response to saline loading are blunted markedly when renal perfusion pressure is reduced immediately before, but not after, the volume load. To ascertain the mechanism responsible for these differences between early clamp (EC) vs. late clamp (LC), intracapillary and interstitial determinants of peritubular capillary uptake of APR were measured in seven LC and seven EC Munich-Wistar rats before and after isotonic saline loading (8% body wt). With volume expansion in LC animals, we observed a marked decline in APR (averaging 11 ± 1 nl/min), associated with large increases in urinary sodium excretion rate, which averaged 8±2 ,ueq/min. In EC, the changes in urinary sodium excretion rate (+1±0 ,eq/min) and APR (-3± 1 nl/min) with volume expansion were smaller in magnitude. Since peritubular capillary reabsorption coefficient and mean peritubular transcapillary hydraulic pressure difference did not change with saline loading in LC, the marked fall in APR was attributed primarily to a measured large decline in mean peritubular transcapillary oncotic pressure difference (AII). Despite an equivalent mean fall in AH with volume expansion in EC, near-constancy of APR was found to be associated with a simultaneous and equivalent decline in mean peritubular transcapillary hydraulic pressure difference (a consequence of decreased mean peritubular capillary hydraulic pressure), which effectively offset the fall in All. These Portions of these studies were presented at

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“…This rate is simply the cortical lymph flow, as estimated from measured flow rates, divided by the total lymphatic endothelial surface area contained in the cortex. The cortical lymph flow is estimated to be 1.0 pl/min/gm renal cortex or about 75% of the total renal lymph flow of 1.4 pl/min/gm kidney (Deen et al, 1976), since cortical lymphatics represent about 75% of total intrarenal lymphatic surface area (O'Morchoe et al, 1982). Additionally, Wolgast et al (1981) found that the cortex is about 70% of the total renal weight in rats.…”

Section: Discussionmentioning

confidence: 99%

The renal cortical lymphatic system in the rat, hamster, and rabbit

et al. 1986

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Rat, hamster, and rabbit renal cortical lymphatics were examined by light and electron microscopy. Rat and hamster kidneys possessed both intra- and interlobular lymphatics that were structurally similar at the light microscopic level. Ultrastructural examination of the hamster lymphatic endothelium, however, revealed an unusual arrangement of cytoplasmic extensions not seen in the other two species. The intralobular lymphatics were related primarily to tubules, afferent arterioles, and renal corpuscles and were consistent with lymph formation from both plasma filtrate and tubular reabsorbate. Interlobular lymphatics were seen in connective tissue associated with the interlobular blood vessels. Rabbit cortex contained only interlobular lymphatics. Cross-sectional area, maximum diameter, volume density, and profile density were determined by stereological measurements using a computer-based image analyzer. The morphological data from the rat were used, in combination with published values for lymph flow, to calculate the rate of lymph formation per unit area of endothelium in lymphatics of the renal cortex. Among kidneys fixed by retrograde perfusion, the cortical lymphatic system was most extensive in maximum diameter, volume density, and profile density. It was smallest in the rabbit and intermediate in the rat. Lower volume and profile density were found for rat kidneys fixed by the dripping technique. It was concluded that: tubular reabsorbate probably contributes to renal lymph in the rat and hamster, but not in the rabbit; significant differences exist in the extent of the renal lymphatic systems among the three species, with the hamster kidney having the richest network and the rabbit the poorest; the method of fixation influences the measured size and density of renal cortical lymphatics; and the estimated rate of lymph formation in the kidney of the rat is roughly comparable to that in the dog.

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Permeability of renal peritubular capillaries to neutral dextrans dextrans and endogenous albumin

Cited by 40 publications

References 0 publications

Blood flow dependence of postglomerular fluid transfer and glomerulotubular balance.

Blood flow dependence of postglomerular fluid transfer and glomerulotubular balance.

Mechanism of Inhibition of Proximal Tubule Fluid Reabsorption after Exposure of the Rat Kidney to the Physical Effects of Expansion of Extracellular Fluid Volume

The renal cortical lymphatic system in the rat, hamster, and rabbit

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