Transtubul�re Natriumchloridfl�sse und Permeabilit�t f�r Nichtelektrolyte im proximalen und distalen Konvolut der Rattenniere

Gertz, K. H.

doi:10.1007/bf00363499

Cited by 260 publications

(116 citation statements)

References 17 publications

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“…increased, on the average, from 0.10% (range = 0.03-0.24%) before furosemide, to 19.5% (range = 12.6-27.8%) after the drug. Similarly, the percentage of filtered volume excreted (V/GFR X 100) rose from 0.30% (range = 0.25-0.42%) to 20.2% (range = 13.5-28.6%) ( Table I).…”

Section: Resultsmentioning

confidence: 92%

“…to a large extent, inferential evidence, it has been widely held until recently that the cross-sectional area of the lumen of the proximal tubule is the principal determinant of the rate of sodium reabsorption by this segment (19)(20)(21)(22). More recent studies in the rat (11,23) and rabbit (24) have provided information that strongly opposes this interpretation.…”

Section: Discussionmentioning

confidence: 99%

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An inhibitory effect of furosemide on sodium reabsorption by the proximal tubule of the rat nephron

Brenner¹,

Keimowitz²,

Wright³

et al. 1969

J. Clin. Invest.

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Section: Resultsmentioning

confidence: 92%

Section: Discussionmentioning

confidence: 99%

An inhibitory effect of furosemide on sodium reabsorption by the proximal tubule of the rat nephron

Brenner¹,

Keimowitz²,

Wright³

et al. 1969

J. Clin. Invest.

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“…Reabsorptive rates (nl. mm-' min') were calculated using the formula: reabsorptive rate = 0-693 rrr2/tj where r is the mean radius of the droplet (Gertz, 1963). There were a total of eighty-seven observations (ten animals) in virgins, seventy-five observations (eight animals) in 6 day, sixty-eight observations (eight animals) in 12 day and seventy-six observations (nine animals) in 19 day pregnant animals.…”

Section: Methodsmentioning

confidence: 99%

Micropuncture study of changes in glomerular filtration and ion and water handling by the rat kidney during pregnancy

Garland

Green

1982

The Journal of Physiology

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SUMMARY1. In rats receiving 200 gl. min-sodium chloride, glomerular filtration rate, single nephron glomerular filtration rate, and fractional reabsorption were measured at various points along the nephron, and ionic concentrations measured in early distal tubular fluid in virgin and 6, 12 and 19 day pregnant rats.2. Glomerular filtration increased progressively until the twelfth day ofpregnancy. At 19 days of pregnancy the glomerular filtration rate, while still above virgin levels, was reduced below 12 day pregnant levels.3. Single nephron glomerular filtration rates measured in proximal and distal tubules were different at both 12 and 19 days of pregnancy, indicating an alteration of tubuloglomerular feed-back. 4. A change in the ratio ofglomerular filtration rate: distal single nephron filtration rate indicated a redistribution of glomerular filtrate to juxtamedullary nephrons by the sixth day of pregnancy.5. Fluid reabsorption is similar up to the early distal tubule but it is not possible to say whether reabsorption is the same in proximal tubules. More fluid is reabsorbed by late distal tubules and collecting ducts in 12 and 19 day pregnant animals than in the virgin and 6 day pregnant animals.6. Changes in ion reabsorption by the loop of Henle occurred during pregnancy; sodium reabsorption was increased by the sixth day of pregnancy and potassium reabsorption by the twelfth day.

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“…Inulin, and PAH clearances and filtration 1 fraction (FF) were calculated from standard equations (17). e During each of the three clearance perieds described above, the reabsorptive half-time (ti) of isolated columns of isotonic NaCl (150 mEq/liter) injected into the lumen of surface proximal convolutions was measured by the split oil drop method of Gertz (18). During the second and third clearance periods, tj measurements were started within 2-3 min after renal perfusion pressure had been changed abruptly by adjustment of the clamp.…”

mentioning

confidence: 99%

“…The aortic clamp was then released, the rapid infusion continued for another 30 min, and a second blood sample collected for hormone assay. All plasma samples were dialyzed against an equal volume of isotonic saline for [18][19][20][21][22][23][24] hr at 50C in acrylic plastic cells (Chemical Rubber Co., Cleveland, Ohio) with a Visking semipermeable membrane (Union Carbide Corp., Chicago, Ill.) separating the two half cells. Neither the plasmas nor the dialysates were pooled.…”

mentioning

confidence: 99%

Effect of changes in renal perfusion pressure on the suppression of proximal tubular sodium reabsorption due to saline loading

Bank¹,

Koch²,

Aynedjian³

et al. 1969

J. Clin. Invest.

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AIB S T R A C T Rapid intravenous infusion of saline isknown to suppress reabsorption of sodium and water in the proximal tubule. It has previously been shown that this suppression is accompanied by two changes which in combination might account for the over-all decrease in reabsorption: a reduction in the intrinsic reabsorptive capacity of the tubular epithelium (C/rr') and a reduction in the ratio between tubular volume and GFR (7rrd/Vo). The present micropuncture experiments were carried out in order to study the possible role of altered peritubular physical forces (hydrostatic and colloid oncotic pressure) in mediating these two changes. Proximal tubular reabsorptive capacity, transit time, fractional reabsorption of sodium and water, 7rrd/Vo, and intratubular hydrostatic pressure were measured in salineloaded rats during acute changes in renal perfusion pressure induced by intermittent constriction of the abdominal aorta.We found that when renal perfusion pressure was lowered to 70-90 mm Hg, the usual effects of saline loading on C/irr, 7rrd/Vo, and fractional reabsorption in the proximal tubule were greatly minimized. When the aortic clamp was released and renal perfusion pressure allowed to rise, C/irr', 7rrd/Vo, and fractional reabsorption fell markedly to levels characteristically seen in saline diuresis. Reclamping of the aorta reversed all of these changes.In order to determine whether the changes in C/rr' accompanying changes in renal perfusion pressure were mediated by a circulating natriuretic hormone, we assayed in hydopenic rats the dialysate of plasma collected from saline-loaded rats during and after release of aortic constriction by the split oil drop method. No Dr. Norman Bank is a Career Scientist of the Health Research Council of New York City.Received for publication 21 June 1968 and in revised form 9 October 1968. significant difference in reabsorptive half-time (ti) was found between the two dialysates, and ti with both dialysates was approximately the same as was found when isotonic saline was injected in the tubules of hydropenic control animals. These observations suggest that the large changes in C/rr' which occurred with changes in renal perfusion pressure in saline-loaded rats were not mediated by a circulating hormone. We suggest that the reduction in C/ir', wr'd/Vo, and fractional reabsorption which occurs in the proximal tubule during a saline diuresis is related to the rise in hydrostatic pressure within the kidney. INTRODUCTIONIt is now well established that the increase in urinary excretion of sodium which occurs during acute saline loading is due to a decrease in sodium reabsorption by the tubules rather than to an increase in the amount of sodium filtered by the glomeruli (1-8). The mechanism (or mechanisms) responsible for this decrease in tubular reabsorption is not entirely clear. It has been shown by Rector, Sellman, Martinez-Maldonado, and Seldin (9) that acute saline loading in the rat is accompanied by two changes in the proximal tubule: a reduction in the intrins...

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Transtubul�re Natriumchloridfl�sse und Permeabilit�t f�r Nichtelektrolyte im proximalen und distalen Konvolut der Rattenniere

Cited by 260 publications

References 17 publications

An inhibitory effect of furosemide on sodium reabsorption by the proximal tubule of the rat nephron

An inhibitory effect of furosemide on sodium reabsorption by the proximal tubule of the rat nephron

Micropuncture study of changes in glomerular filtration and ion and water handling by the rat kidney during pregnancy

Effect of changes in renal perfusion pressure on the suppression of proximal tubular sodium reabsorption due to saline loading

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