A micropuncture study of the relationship between flow-rate through the loop of Henle and sodium concentration in the early distal tubule

Cortney, Marshall A.; Nagel, Wolfram; Thurau, Klaus

doi:10.1007/bf00362490

Cited by 45 publications

(10 citation statements)

References 9 publications

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“…The mechanism responsible for this is ngt clear. It is possible that this reflects a limitation of sodium transport in the ascending limb at high rates of flow through the loop of Henle (24,25) or is the result of an impairment of active sodium transport in the ascending limb due to altered interstitial factors which affect peritubular capillary absorption, evidence for which has been presented in the proximal tubule (26).…”

Section: Discussionmentioning

confidence: 99%

Micropuncture study of hypertonic mannitol diuresis in the proximal and distal tubule of the dog kidney

Seely¹,

Dirks²

1969

J. Clin. Invest.

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A B S T R A C T Fractional reabsorption of water, sodium, and potassium at proximal and distal tubular sites within the nephron was studied by recollection-micropuncture experiments on dogs undergoing hypertonic mannitol diuresis. After an initial control hydropenic phase, 16% mannitol in modified Ringer's solution was administered intravenously, resulting in marked increases in fractional excretion of water (28.7%), sodium (12.6%), and potassium (63.9%). Inulin clearance decreased significantly from 35.1 to 25.2 ml/min. Analysis of paired micropuncture data revealed a significant decrease in tubule fluid to plasma (TF: P) inulin ratios in both the proximal tubule (1.63-1.45) and distal tubule (5.38-1.94). There was also a significant decrease in proximal TF: P sodium ratios (0.99-0.93) and potassium ratios (1.05-0.98). Distal TF: P sodium ratios, in contrast, rose significantly (0.38-0.59), while TF: P potassium ratios tended towards unity whether initially greater or less than one. Fractional reabsorption of sodium and water decreased by 5% and 10% respectively in the proximal tubule, but to a lesser extent than the resulting increases in fractional urinary excretion. The nonreabsorbed fraction, however, had increased sharply at the point of distal puncture for water (32%), sodium (26%), and potassium (26%), indicating a large inhibitory effect within the loop of Henle in addition to the smaller proximal effects.

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Section: Discussionmentioning

confidence: 99%

Micropuncture study of hypertonic mannitol diuresis in the proximal and distal tubule of the dog kidney

Seely¹,

Dirks²

1969

J. Clin. Invest.

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“…It is widely accepted that the MD presumably represents a sensor capable of detecting the changes in concentrations of some critical substance. The function sensed could be Na concentration [18], glucose [19], osmolality [20], or adenosine [21]. It is not far fetched to postulate that specific substances, including peptides, could reach the sensor through filtration and/or tubular reabsorption and secretion.…”

Section: Discussionmentioning

confidence: 99%

Effect of Endothelin 1 on Proximal Reabsorption and Tubuloglomerular Feedback

Romano¹,

Giagu²,

Favret³

et al. 2000

Kidney Blood Press Res

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Endothelin 1 (ET–1) is a powerful constrictor of the afferent glomerular artery, implicated in the occurrence of both functional and acute renal failure. Besides being produced by the endothelium, ET–1 is also secreted by proximal tubular cells, suggesting that it may act as an endoluminal messenger. The present study is intended to verify whether ET–1 may play a role in the tubuloglomerular feedback system. The experiments were performed in rat superficial glomeruli. In 25 nephrons we measured by the total collection technique the single–nephron glomerular filtration rate (SNGFR; nl/min) and reabsorption rates before (control) and during microinjection (MIJ) of ET–1 10^–7 M into the first proximal convolution or Bowman’s space. The SNGFR rose from 27±3 to 61±11 nl/min (p<0.01), the percent proximal reabsorption rose from 43 to 74%, and the absolute reabsorption rose from 13±2 to 46±11 nl/min (p<0.01). In additional 23 nephrons the collections were performed at the earliest distal convolution accessible on the renal surface, while MIJ was performed in the last proximal convolution of the same nephrons. The SNGFR rose during MIJ from 22±3 to 40±6 nl/min (p<0.01), the percent reabsorption rose from 61 to 66% (p>0.77), and the absolute reabsorption rose from 12±2 to 26±4 nl/min, (p<0.003). Exposure of the macula densa to intraluminally injected ET–1 causes an abrupt increase in SNGFR of the experimental nephron, in the absence of changes in systemic and renal hemodynamics. During proximal MIJ, ET–1 may have reached the macula densa during the time preceding the beginning of collection and interruption of the delivery of fluid to the distal nephron. ET–1 directly stimulates fractional and absolute volume reabsorption along the proximal tubule. Proximal secretion and/or filtration of ET–1 could represent a physiological mechanism to activate the tubuloglomerular feedback, eliciting a response opposite to that triggered by systemic and intrarenal infusion.

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“…They proposed the following sequence: increased renin release, local angiotensin II formation, afferent arteriolar constriction, and a de creased glomerular filtration rate with resultant proximal tubule collapse. Other data that support this hypothesis include: the presence of myofibrils in the juxtaglomerular cells [47], the presence of renin substrate and coverting enzyme for angiotensin in the juxtaglomerular apparatus [44] and the presence of denovo angiotensin II in renal lymph [4], Schnerm a n n [87], however, could not confirm the original observations of C ortney et al [29], and found that the sodium concentration in the early distal tubule was not necessarily de pendent upon delivery rate. In fact, both Schnerm a n n et al [88] and M o r g a n and Berliner [69] noted that sodium concentration was high at very low delivery rates, then fell, but rose once again at perfusion rates greater than 20 nl/min in late proximal tubules.…”

Section: Autoregulationmentioning

confidence: 40%

“…This hypothe sis received its first experimental support in 1964 when Vander and M iller [114] found that the increased renin release induced by aortic constriction could be obviated with chlorothiazide, acetazolamide, or mannitol. Subse quent studies demonstrated that the increased renin release seen with elevated ureteral pressure [114], infusion of catecholamines at a constant renal per fusion pressure [29], and renal nerve stimulation [115] could be blocked with mannitol, sodium sulfate, chlorothiazide or acetazolamide. It was suggested that an inverse relationship existed between sodium delivery to the macula densa and renin release.…”

Section: Macula Densa Theorymentioning

confidence: 99%

Renin and the Kidney

Chonko¹,

Stein²,

Ferris³

1975

Nephron

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The factors involved in renin release have been extensively evaluated. The primary determinants are the transmural pressure at the afferent arteriole, sodium delivery to the macula densa, and the activity of the adrenergic nervous system. Other possible factors include circulating catecholamines, the serum and cerebrospinal fluid sodium concentration, serum potassium concentration, angiotensin II concentration, and antidiuretic hormone release. There is no convincing evidence that the renin-angiotensin system mediates renal autoregulation. Plasma renin activity is altered in a number of clinical settings. This parameter is elevated in most patients with cirrhosis and the nephrotic syndrome as well as in individuals with severe congestive heart failure. Despite inappropriately large weight gains, plasma renin suppresses normally with increased salt intake in edematous patients who have a normal glomerular filtration rate. The mechanisms of the alteration in the renin-angiotensin system in Bartter’s syndrome is still not clear.

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A micropuncture study of the relationship between flow-rate through the loop of Henle and sodium concentration in the early distal tubule

Cited by 45 publications

References 9 publications

Micropuncture study of hypertonic mannitol diuresis in the proximal and distal tubule of the dog kidney

Micropuncture study of hypertonic mannitol diuresis in the proximal and distal tubule of the dog kidney

Effect of Endothelin 1 on Proximal Reabsorption and Tubuloglomerular Feedback

Renin and the Kidney

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