scholarly journals The effect of pregnancy on glomerular filtration rate and salt and water reabsorption in the rat.

1981 ◽  
Vol 319 (1) ◽  
pp. 153-164 ◽  
Author(s):  
J C Atherton ◽  
S C Pirie
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Water Reabsorption

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.

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.

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.

Mechanisms of Post-Obstructive Diuresis in the Solitary Hydronephrotic Kidney of the Rat

1975 ◽  
Vol 48 (3) ◽  
pp. 167-176
Author(s):  
D. R. Wilson
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Urine Osmolality ◽  
Urine Flow ◽  
Control Group ◽  
Water Reabsorption ◽  
Hydronephrotic Kidney ◽  
Remnant Kidney

1. In order to clarify further the phenomenon of post-obstructive diuresis, clearance and micro-puncture experiments were done before and after relief of partial ureteral obstruction in rats with a solitary hydronephrotic kidney. 2. Glomerular filtration rate, urine flow and sodium excretion increased markedly, whereas surface nephron glomerular filtration rate increased only slightly and intratubular pressure, proximal and distal tubular water reabsorption did not change significantly. Decreased tubular reabsorption in deeper nephrons and collecting ducts appeared to be of major importance in the post-obstructive diuresis after relief of chronic obstruction. 3. In order to examine further the distinctive functional characteristics of the chronically hydronephrotic kidney, the results were compared with control rats having a solitary normal kidney or a solitary remnant kidney with an intact renal medulla. Urine flow rate and sodium excretion were higher and urine osmolality was lower (P < 0.01) in post-obstructive kidneys when compared with either control group. There were no differences in glomerular filtration rate or surface nephron function which could account for the greater diuresis and natriuresis from the hydronephrotic kidney, thus confirming the importance of an abnormality in deep nephron or medullary function in post-obstructive diuresis. 4. There was a greater diuresis in post-obstructive rats with a marked increase in blood urea concentration. Water reabsorption in the distal nephron was decreased in such animals, as well as in urea-loaded rats with a remnant kidney, indicating the probable mechanism by which urea diuresis potentiates the phenomenon of post-obstructive diuresis.

Reversible hemodynamic defect in glomerular filtration rate after ischemic injury

1975 ◽  
Vol 228 (5) ◽  
pp. 1436-1439 ◽  
Author(s):  
TM Daugharty ◽  
BM Brenner
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Ischemic Injury ◽  
Left Renal Artery ◽  
Water Reabsorption ◽  
Ischemic Lesion ◽  
Glomerular Capillary ◽  
Single Nephron ◽  
Ultrafiltration Pressure

In Wistar rats with surface glomeruli 3 h of nearly complete occlusion of the left renal artery resulted in uniform falls (similar to50%) in ipsilateral whole-kidney glomerular filtration rate (GFR) and single-nephron GFR (SNGFR) and in urinary findings consistent with impaired water reabsorption. Since the fall in SNGFR was accompanied by a proportional fall in glomerular plasma flow rate (GPF), and since net ultrafiltration pressure at afferent and efferent ends of the glomerular capillary was unchanged from preischemic levels, these findings suggest that the fall in SNGFR was a hemodynamic consequence of the fall in GPF. To test this hypothesis, GPF was restored to preischemic levels by means of acute infusion of homologous, isoncotic plasma. GPF and SNGFR uniformly increased, on average to preischemic levels, whereas net ultrafiltration pressure at afferent and efferent ends of the glomerular capillary again remained essentially unchanged. These studies demonstrate that the fall in SNGFR in this model of ischemic injury is causally related to the accompanying fall in GPF. Of interest, despite this reversal of the defect in GFR, fractional water reabsorption remained impaired. This restoration of GFR but not reabsorption by plasma infusion abruptly converts this ischemic lesion from nondiuretic to diuretic.

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