Physical Factors Influencing Fluid Reabsorption from Henle's Loop

1975 ◽  
Vol 53 (2) ◽  
pp. 224-230 ◽  
Author(s):  
A. D. Baines ◽  
C. K. Wu
Keyword(s):  
Glomerular Filtration Rate ◽  
Flow Velocity ◽  
Glomerular Filtration ◽  
Transit Time ◽  
Filtration Rate ◽  
Physical Factors ◽  
Water Reabsorption ◽  
Fluid Reabsorption ◽  
Henle's Loop ◽  
Loop Volume

Our objective was to produce reductions in the luminal volume of Henle's loop and increases in linear flow velocity through the loop. We did this in a recollection micropuncture study by collecting fluid with and without suction from early distal tubules. With suction, transit time of fast green dye through the loop decreased by 34%, calculated loop volume decreased by 28%, and fractional water reabsorption fell from 73.6 to 70.3% (p < 0.025) in water diuretic rats. Absolute water reabsorption did not decrease significantly. In urea–saline diuretic rats transit time decreased 25%, calculated loop volume decreased 22%, fractional reabsorption fell from 59.0 to 51.7% (p < 0.001), and absolute reabsorption decreased by 2.3 nl/min(p < 0.025). Single nephron glomerular filtration rate, distal tubular sodium concentration, and osmolality were unaffected. The less pronounced effect of collection with suction in water diuretic rats may be related to the lower medullary fluid osmolality, which was 338 ± 9(S.E.)mOsmol/kg as compared to497 ± 35 in urea–saline diuretic rats. Collecting fluid with suction from late proximal tubules did not alter glomerular filtration rate or fractional water reabsorption. Stumpe et al. ((1970) J. Clin. Invest. 49, 1200–1212) noted an inverse correlation between fluid reabsorption from Henle's loop and flow velocity in rats with hypertension or congestive heart failure. One can reproduce this correlation by artificially altering the transmural pressure gradient in the loop.

Glomerular Filtration Rate and Segmental Tubular Function in the Early Phase after Transplantation/Uninephrectomy in Recipients and Their Living-Related Kidney Donors

1994 ◽  
Vol 87 (5) ◽  
pp. 519-523 ◽  
Author(s):  
Anne-Lise Kamper ◽  
Niels-Henrik Holstein-Rathlou ◽  
Svend Strandgaard ◽  
Paul Peter Leyssac ◽  
Ole Munck
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Sodium Reabsorption ◽  
Lithium Clearance ◽  
Kidney Donors ◽  
Fluid Reabsorption ◽  
Living Related ◽  
Reabsorption Rate ◽  
Sodium Clearance

1. Glomerular filtration rate and sequential tubular function were investigated in 18 adult renal transplant recipients and in their matched, adult living-related kidney donors before and 5 days after transplantation/uninephrectomy. At day 54, 13 donors and 11 recipients were re-investigated. Sixteen of these constituted eight matched pairs. This reduction in the study population was caused by the application of two withdrawal criteria. 2. In the recipients glomerular filtration rate was unchanged at day 5 and had increased to 61 ml/min at day 54 (P < 0.05). In the donors glomerular filtration rate had increased to 59 ml/min by day 5 (P < 0.01) and was unchanged at day 54. 3. In the recipients lithium clearance was unchanged at day 5 and had increased to 23 ml/min at day 54 (P < 0.01). In the donors the lithium clearance had increased by day 5 (P < 0.01). 4. In the recipients the absolute proximal fluid reabsorption rate was about 36 ml/min throughout the study period. In the donors the absolute proximal fluid reabsorption rate had increased to 42 ml/min by day 5 (P < 0.05) and increased further to 44 ml/min by day 54 (P < 0.01). 5. In the recipients sodium clearance increased from 0.54 ml/min to 2.10 ml/min at day 54 (P < 0.01). In the donors it increased from 0.64 ml/min to 0.99 ml/min at day 54 (P < 0.05). 6. Donor-recipient comparison showed that at day 54 there was no significant difference with regard to glomerular filtration rate, lithium clearance, absolute and fractional proximal fluid reabsorption rate and absolute distal sodium reabsorption rate. The sodium clearance was higher and the fractional distal sodium reabsorption rate was lower in the recipients. 7. In conclusion, the difference in function between donors and recipients at day 5 can probably be explained by the damaging effect of many inevitable factors on the graft. Fifty-four days after transplantation the function of the graft could not be distinguished from that of the remaining kidney. This suggests that the ideal homograft possesses a normal potential for compensatory hypertrophy once the effects of the initial post-operative ischaemia and toxic factors have subsided.

THE EFFECT OF HYPOPHYSECTOMY AND CORTICOTROPHIN ON THE RENAL SENSITIVITY TO ANTIDIURETIC HORMONE

1967 ◽  
Vol 38 (2) ◽  
pp. 107-114 ◽  
Author(s):  
J. W. BAUMAN
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Antidiuretic Hormone ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Normal Values ◽  
Renal Plasma Flow ◽  
Free Water ◽  
Water Reabsorption ◽  
Hypophysectomized Rats

SUMMARY Glomerular filtration rate (GFR), renal plasma flow (RPF) and solute-free water reabsorption (TcH2O) were measured in anaesthetized intact and hypophysectomized rats and in hypophysectomized rats treated with corticotrophin (ACTH). GFR and RPF were measured by [14C]inulin and [3H]p-aminohippuric acid clearances. In agreement with previous reports, these two functions were found to be reduced by hypophysectomy. Infusion of vasopressin increased TcH2O in the intact rat but failed to produce a significant change in the hypophysectomized rat. Treatment of hypophysectomized rats with ACTH restored the effects of vasopressin on TcH2O. ACTH also increased the RPF of hypophysectomized rats to normal values, but only partially restored GFR.

Measuring dynamic kidney function in an undergraduate physiology laboratory

2013 ◽  
Vol 37 (4) ◽  
pp. 384-391 ◽  
Author(s):  
Scott Medler ◽  
Frederick Harrington
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Urine Concentration ◽  
Renal Physiology ◽  
Water Reabsorption ◽  
Laboratory Courses ◽  
Physiological Processes ◽  
Estimate Glomerular Filtration Rate ◽  
Physiology Laboratory

Most undergraduate physiology laboratories are very limited in how they treat renal physiology. It is common to find teaching laboratories equipped with the capability for high-resolution digital recordings of physiological functions (muscle twitches, ECG, action potentials, respiratory responses, etc.), but most urinary laboratories still rely on a “dipstick” approach of urinalysis. Although this technique can provide some basic insights into the functioning of the kidneys, it overlooks the dynamic processes of filtration, reabsorption, and secretion. In the present article, we provide a straightforward approach of using renal clearance measurements to estimate glomerular filtration rate, fractional water reabsorption, glucose clearance, and other physiologically relevant parameters. The estimated values from our measurements in laboratory are in close agreement with those anticipated based on textbook parameters. For example, we found glomerular filtration rate to average 124 ± 45 ml/min, serum creatinine to be 1.23 ± 0.4 mg/dl, and fractional water reabsorption to be ∼96.8%. Furthermore, analyses for the class data revealed significant correlations between parameters like fractional water reabsorption and urine concentration, providing opportunities to discuss urine concentrating mechanisms and other physiological processes. The procedures outlined here are general enough that most undergraduate physiology laboratory courses should be able to implement them without difficulty.

EFFECT OF DEHYDRATION PRODUCED BY WATER DEPRIVATION, DIARRHEA AND VOMITING ON RENAL FUNCTION IN INFANTS

PEDIATRICS ◽  
1951 ◽  
Vol 7 (3) ◽  
pp. 328-340
Author(s):  
PHILIP L. CALCAGNO ◽  
MITCHELL I. RUBIN
Keyword(s):  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Intravenous Administration ◽  
Water Conservation ◽  
Filtration Rate ◽  
Water Deprivation ◽  
Diarrheal Disease ◽  
Normal Values ◽  
Water Reabsorption

Dehydration when of sufficient severity depresses the glomerular filtration rate significantly. The high inulin and creatinine U/P ratios during dehydration indicate water conservation by the tubules. Depressed glomerular filtration rates may enhance this mechanism. The tendency to the lower than expected rise in U/P ratio with low urine flows during dehydration in diarrheal disease suggests disturbed tubular mechanism for water reabsorption. Glomerular filtration rate is rapidly restored with the intravenous administration of fluid. Restoration to normal values may proceed at a slower pace in the sick infant.

Renal water reabsorption during saline and urea osmotic diuresis in the dog

1963 ◽  
Vol 205 (3) ◽  
pp. 477-482 ◽  
Author(s):  
David L. Maude ◽  
Laurence G. Wesson
Keyword(s):  
Glomerular Filtration Rate ◽  
Steady State ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Free Water ◽  
Conscious Dogs ◽  
Water Reabsorption ◽  
Osmotic Diuresis ◽  
Sodium Salts

Free water reabsorption (Twc) was measured in conscious dogs during a long-term, reasonably steady-state osmotic diuresis induced either by sodium salts or by urea. After 4 to 8 hr the original solute was partially replaced by urea or by sodium salts. Both the replacement of sodium salts by urea and the converse procedure were associated with an augmentation in Twc. During sodium diuresis Twc always fell during the first 2 or 3 hr, a change which appeared unrelated to glomerular filtration rate (GFR) or to osmolar clearance. During the course of urea diuresis Twc steadily increased and showed a positive correlation with GFR. A possible basis for such a correlation is discussed.

A Micropuncture Study of Proximal Tubular Function after Acute Hydrochlorothiazide Administration to Brattleboro Rats with Diabetes Insipidus

1979 ◽  
Vol 57 (5) ◽  
pp. 427-434 ◽  
Author(s):  
S. J. Walter ◽  
J. F. Laycock ◽  
D. G. Shirley
Keyword(s):  
Glomerular Filtration Rate ◽  
Diabetes Insipidus ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Inhibitory Effect ◽  
Tubular Reabsorption ◽  
Brattleboro Rats ◽  
Fluid Reabsorption ◽  
Proximal Tubular ◽  
Proximal Tubular Reabsorption

1. Renal function in anaesthetized Brattleboro rats with hereditary hypothalamic diabetes insipidus was studied with micropuncture techniques before, and 1–3 h after, a single injection of hydrochlorothiazide. 2. In rats given hydrochlorothiazide and kept in sodium and water balance, total glomerular filtration rate and superficial nephron filtration rate were similar to values in control animals, whereas fractional fluid reabsorption in the proximal tubule (as evidenced by tubular fluid/plasma inulin concentration ratios) was slightly, but significantly, reduced. This suggests that hydrochlorothiazide may have a small direct inhibitory effect on proximal tubular reabsorption. 3. When rats were given hydrochlorothiazide and the resultant extra urinary sodium losses were not replaced, there was a marked antidiuresis. In these animals total glomerular filtration rate was reduced by 23% and superficial nephron filtration rate by 27% when compared with values in control rats. Fractional proximal tubular fluid reabsorption increased significantly whereas absolute proximal fluid reabsorption was unaffected. 4. It is concluded that the reduction in body sodium which follows acute hydrochlorothiazide administration over-rides any inhibitory effect of the drug on proximal tubular reabsorption, and leads instead to an increase in fractional fluid reabsorption at this site. This effect, combined with the fall in glomerular filtration rate, results in a greatly reduced delivery of fluid to the more distal nephron segments, and is probably largely responsible for the observed antidiuresis.

scholarly journals Nephron filtration rate and proximal tubular fluid reabsorption in the Akita mouse model of type I diabetes mellitus

F1000Research ◽  
2013 ◽  
Vol 2 ◽  
pp. 83 ◽  
Author(s):  
Jurgen Schnermann ◽  
Mona Oppermann ◽  
Yuning Huang
Keyword(s):  
Diabetes Mellitus ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Type I Diabetes ◽  
Type I ◽  
Fluid Reabsorption ◽  
Single Nephron ◽  
Proximal Tubular ◽  
Tubular Fluid Reabsorption

An increase of glomerular filtration rate (hyperfiltration) is an early functional change associated with type I or type II diabetes mellitus in patients and animal models. The causes underlying glomerular hyperfiltration are not entirely clear. There is evidence from studies in the streptozotocin model of diabetes in rats that an increase of proximal tubular reabsorption results in the withdrawal of a vasoconstrictor input exerted by the tubuloglomerular feedback (TGF) mechanism. In the present study, we have used micropuncture to assess single nephron function in wild type (WT) mice and in two strains of type I diabetic Ins2+/- mice in either a C57Bl/6 (Akita) or an A1AR-/- background (Akita/A1AR-/-) in which TGF is non-functional. Kidney glomerular filtration rate (GFR) of anesthetized mice was increased by 25% in Akita mice and by 52% in Akita/A1AR-/-, but did not differ between genotypes when corrected for kidney weight. Single nephron GFR (SNGFR) measured by end-proximal fluid collections averaged 11.8 ± 1 nl/min (n=17), 13.05 ± 1.1 nl/min (n=23; p=0.27), and 15.4 ± 0.84 nl/min (n=26; p=0.009 compared to WT; p=0.09 compared to Akita) in WT, Akita, and Akita/A1AR-/- mice respectively. Proximal tubular fluid reabsorption was not different between WT and diabetic mice and correlated with SNGFR in all genotypes. We conclude that glomerular hyperfiltration is a primary event in the Akita model of type I diabetes, perhaps driven by an increased filtering surface area, and that it is ameliorated by TGF to the extent that this regulatory system is functional.

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