Early postglomerular plasma concentrations of chloride, sodium, and inulin in the rat kidney

1976 ◽  
Vol 231 (3) ◽  
pp. 822-831 ◽  
Author(s):  
SW Weinstein ◽  
J Szyjewicz
Keyword(s):  
Sodium Chloride ◽  
Proximal Tubule ◽  
Blood Supply ◽  
Functional Relationship ◽  
Rat Kidney ◽  
Plasma Concentrations ◽  
Chloride Concentration ◽  
Sodium Concentration ◽  
Peripheral Plasma ◽  
Proximal Tubular

Sodium, chloride, and inulin concentrations were measured in plasma collected from the terminal portions of long efferent vessels at the subcapsular surface of the rat kidney. Sodium concentration equaled and the concentrations of chloride and inulin were less than those in peripheral plasma. During benzolamide infusion, chloride concentration equaled while inulin concentration remained less than in peripheral plasma. In free-flow micropuncture samples collected randomly during control conditions, chloride concentration rose rapidly in the early proximal tubule and then remained elevated and constant throughout the remainder of the proximal tubule accessible to micropuncture. These experiments indicate that normally tubular reabsorbate low in chloride and inulin is added to the blood traversing the early postglomerular vessels before reaching the kidney surface. Bases on the analyses of proximal tubular fluid, this type of reabsorbate appears available only from the early proximal tubular segment. We conclude that a close functional relationship exists between the first segment of the proximal tubule and the early postglomerular blood supply characteristic of the superficial cortical nephron.

Role of luminal hydrostatic pressure in proximal tubular fluid reabsorption in the rat

1975 ◽  
Vol 229 (3) ◽  
pp. 813-819 ◽  
Author(s):  
A Grandchamp ◽  
Scherrer ◽  
D Scholer ◽  
J Bornand
Keyword(s):  
Hydrostatic Pressure ◽  
Proximal Tubule ◽  
Pressure Difference ◽  
Unit Area ◽  
Rat Kidney ◽  
Fluid Reabsorption ◽  
Proximal Tubular ◽  
Tubular Fluid Reabsorption ◽  
Selective Change

The effect of small changes in intraluminal hydrostatic pressure (P) on the tubular radius (r) and the net fluid reabsorption per unit of surface area of the tubular wall (Js) has been studied in the proximal tubule of the rat kidney. The split-drop method was used to simultaneously determine Js and r. Two standardized split-drop techniques A and B allow selective change in P. P was 31.6 +/- 1.3 mmHg in technique A and 15.5 +/- 1.5 in technique B. The pressure difference significantly affected the tubular radius; r was 21.9 +/- 0.4 and 18.6 +/- 0.5 mum in the split drop A and B, respectively. In contrast, net transepithelial fluid reabsorption Js was unchanged. Js amounted to 2.72 +/- 0.20, and 2.78 +/- 0.33 10(-5) cm3 cm-2 s-1 in split drop A and B. The absence of variations in Js could result from two opposite effects of pressure. P might enhance Js by increased ultrafiltration. However, the rise in r might decrease the density of the intraepithelial transport paths per unit area of tubular wall and therefore might decrease Js.

Superficial nephron tubular-vascular relationships in the rat kidney

1978 ◽  
Vol 234 (3) ◽  
pp. F207-F214 ◽  
Author(s):  
S. W. Weinstein ◽  
J. Szyjewicz
Keyword(s):  
Proximal Tubule ◽  
Blood Supply ◽  
Close Contact ◽  
Rat Kidney ◽  
Proximal Region ◽  
Functional Interactions ◽  
Pars Recta ◽  
Physical Forces ◽  
The Relationship ◽  
Early Late

Silicone rubber injections of methyl salicylate-cleared rat kidneys were performed. In 50 of 56 injections of superficial nephrons with their accompanying blood supply, the efferent vessel and early proximal tubule were closely approximated. In 18 of 21 tubular injections filling through the pars recta, the proximal tubule folded upon itself with early and late proximal segments, in close contact, located over their parent glomerulus, and the midproximal segments separate and located over their parent interlobular artery. The distribution of blood was serially through the early-late proximal region above the glomerulus via a long unbranched efferent vessel, via branches over the capsular surface, via capillaries down through the midproximal region, then into the interlobular vein. The observed anatomical pattern of the superficial nephron appears to permit direct functional interactions between the juxtaposed early and late proximal tubule, and in turn may effect midproximal function via the distribution of blood (modified by early proximal) from the efferent vessel to midproximal convolutions. In addition, the relationship between specific segments of the proximal tubule and specific portions of the postglomerular peritubular blood supply may be important in determining the distribution of peritubular physical forces to these nephrons.

scholarly journals Regulation of Water and Some Ions in Gammarids (Amphipoda)

1971 ◽  
Vol 55 (2) ◽  
pp. 357-369
Author(s):  
D. W. SUTCLIFFE
Keyword(s):  
Sodium Chloride ◽  
Sea Water ◽  
Chloride Concentration ◽  
Sodium Concentration ◽  
Body Water ◽  
The Body ◽  
Salinity Range ◽  
Sodium Potassium ◽  
Body Sodium ◽  
Total Body

1. A comparison was made of the body water contents and the concentrations of sodium, potassium and chloride in the blood and body water of Gammarus zaddachi, G. locusta and Marinogammarus finmarchicus. 2. G. zaddachi had a slightly higher body water content than G. locusta and M. finmarchicus. 3. In all three species the blood chloride concentration was lower than the external chloride concentration in 80-113 % sea water, but the blood sodium concentration was equal to or slightly above the sodium concentration in the external medium. 4. The total body sodium concentration was always greater than the total body chloride concentration. In M.finmarchicus the ratio of body sodium/chloride increased from 1.2 to 1.3 over the salinity range 100-20% sea water. In G. zaddachi the ratio of body sodium/chloride increased from 1.08 at 100% sea water to 1.87 in 0.25 mM/l NaCl. 5. The total body potassium concentration remained constant. The potassium loss rate and the balance concentration were relatively high in G. zaddachi. 6. The porportion of body water in the blood space was calculated from the assumption that a Donnan equilibrium exists between chloride and potassium ions in the extracellular blood space and the intracellular space. In G. zaddachi the blood space was equivalent to 60% body H2O at 100% sea water, and equivalent to 50% body H2O at 40% sea water down to 0.5 mM/l NaCl. In M.finmarchicus the blood space was equivalent to 38-44% body H2O at salinities of 20-100% sea water. 7. The mean intracellular concentrations of sodium, potassium and chloride were also calculated. It was concluded that for each ion its intracellular concentration is much the same in the four euryhaline gammarids. The intracellular chloride concentration is roughly proportional to the blood chloride concentration. The intracellular sodium concentration is regulated in the face of large changes in the blood sodium concentration.

scholarly journals Evaluating the influence of Citrullus lanatus seed extracts on electrolytes, urea and creatinine in Streptozotocin induced diabetic albino rats

2018 ◽  
pp. 87-94
Keyword(s):  
Sodium Chloride ◽  
Citrullus Lanatus ◽  
Colorimetric Method ◽  
Chloride Concentration ◽  
Ethanolic Extract ◽  
Sodium Concentration ◽  
Diabetic Control ◽  
Albino Rats ◽  
Potassium Sodium ◽  
Group 1

The focus of current research study was to evaluate the influence of the seed extract of Citrullus lanatus on urea, creatinine, potassium, sodium, chloride and bicarbonate in streptozotocin induced diabetic rats. Eighteen male wistar albino rats were divided into six groups of three rats each, diabetes were induced in all the rats except group 1 by intraperitoneal injection of 45 mg/kg b.wt. of streptozotocin. Group 1 rats served as control and received standard feed and water daily; Group 2 rats received oral Glibenclamide (0.5 mg/kg bw); Group 3,4, and 5 received 200 mg/kg bw, 400 mg/kg bw and 600 mg/kg b.wt. of the ethanolic extract of Citrullus lanatus seed respectively; and group 6 served as diabetic group. Blood samples were collected and analysed for urea, creatinine, potassium, sodium, chloride and bicarbonate using urease-Berthelot colorimetric method, Jaffe’s colorimetric method and Ion selective electrode (ISE) method respectively. There was a significant decrease in (p<0.05) glucose concentration (mmol/L) of 3.90 in control compared to 8.07, 8.73, 14.67, 11.43 and 9.80 in albino rats treated with glibenclamide, STZ+CLS 200 mg, STZ+CLS 400 mg, STZ+CLS 600 mg and diabetic control respectively. In potassium concentration (meq/l) 6.51 in control compared with 4.97, 7.59, 7.28, 8.45 and 6.87 in albino rats treated with glibenclamide, STZ+CLS200 mg, STZ+CLS 400 mg, STZ+CLS 600 mg and diabetic control respectively. While in sodium concentration (meq/l) of 1.42 in control compared to 1.33, 1.30, 1.36, 1.42 and 1.36 in albino rats treated with glibenclamide, STZ+CLS 200 mg, STZ+CLS 400 mg, STZ+CLS 600 mg and diabetic control respectively. However, in chloride concentration (meq/l) of 1.06 in control compared to 99.10, 97.87, 1.04, 88.00, 1.04, 88.00 and 1.04 in albino rats treated with glibenclamide, STZ+CLS 200 mg, STZ+CLS 400 mg, STZ+CLS 600 mg and diabetic control respectively and also in bicarbonate concentration (meq/l) of 10.07 when compared with 17.30, 16.47, 15.40, 6.40 and 17.30 in albino rats treated with glibenclamide, STZ+CLS 200 mg, STZ+CLS 400 mg, STZ+CLS 600 mg and diabetic control respectively. In conclusion, this medicinal plant could be considered as a potential and alternative approach for the treatment of diabetes. Keywords: Keywords: Citrullus lanatus, Diabetes Mellitus, Renal

The Quantab strip in the measurement of urinary chloride and sodium concentrations.

1984 ◽  
Vol 30 (10) ◽  
pp. 1705-1707 ◽  
Author(s):  
P J Sloan ◽  
G Beevers ◽  
F E Baxter
Keyword(s):  
Sodium Chloride ◽  
Chloride Concentration ◽  
Sodium Concentration ◽  
Epidemiological Studies ◽  
Observer Variation ◽  
Salt Diet ◽  
Sodium Chloride Solutions ◽  
Urinary Chloride ◽  
Chemical Assay ◽  
Low Salt

Abstract The "Quantab" strip (Ames) measures chloride in fluids. For sodium chloride solutions and urine we found very good correlations between the Quantab reading and the chloride concentration as measured by chemical assay (r = 0.95 for chloride and r = 0.85 for sodium in urine). The strip gave reproducible results over the temperature range 4 to 37 degrees C. There was very little inter- and intra-observer variation in reading the strip. Although 10 to 23 min is required to complete the reaction, the strip reading is stable thereafter. We suggest that the strip could be useful in epidemiological studies of urinary sodium concentration and clinically in helping patients adhere to a low-salt diet.

scholarly journals Isolation of membrane-bound renal enzymes that metabolize kinins and angiotensins

1976 ◽  
Vol 157 (3) ◽  
pp. 643-650 ◽  
Author(s):  
P E Ward ◽  
E G Erdös ◽  
C D Gedney ◽  
R M Dowben ◽  
R C Reynolds
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Proximal Tubule ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Rat Kidney ◽  
Surface Membrane ◽  
Renal Kallikrein ◽  
Proximal Tubular ◽  
Kallikrein Activity

Cortex of rat kidney was homogenized and fractions enriched in plasma membrane, endoplasmic reticulum or brush border were prepared by several techniques of differential centrifugation. The identity and homogeneity of the membrane fragments were investigated by assaying marker enzymes and by transmission and scanning electron microscopy. Kallikrein was present in both plasma-membrane- and endoplasmic-reticulum-enriched fractions isolated by two fractionation procedures. Kallikrein was highly concentrated in a plasma-membrane fraction but was absent from the brush-border membrane of proximal tubular cells. Cells of transplanted renal tumours of the rat, originating from the proximal tubule, had no kallikrein activity. Kininase activity, angiotensin I-converting enzyme (kininase II) and angiotensinase were found in a plasma-membrane-enriched fraction and especially in the fraction containing isolated brush border. It is suggested that after renal kallikrein is synthesized on endoplasmic reticulum, it is subsequently reoriented to a surface membrane for activation and release. Renal kallikrein may enter the tubular filtrate distal to the proximal tubules. The brush-border membrane of proximal tubule is the major site of inactivation of kinins and angiotensin II..

scholarly journals Modeling oxygen consumption in the proximal tubule: effects of NHE and SGLT2 inhibition

2015 ◽  
Vol 308 (12) ◽  
pp. F1343-F1357 ◽  
Author(s):  
Anita T. Layton ◽  
Volker Vallon ◽  
Aurélie Edwards
Keyword(s):  
Oxygen Consumption ◽  
Proximal Tubule ◽  
Rat Kidney ◽  
Sodium Reabsorption ◽  
Transport Efficiency ◽  
Pathological Conditions ◽  
Sglt2 Inhibition ◽  
Proximal Tubular ◽  
The Individual ◽  
Do So

The objective of this study was to investigate how physiological, pharmacological, and pathological conditions that alter sodium reabsorption (TNa) in the proximal tubule affect oxygen consumption (QO2) and Na+ transport efficiency (TNa/QO2). To do so, we expanded a mathematical model of solute transport in the proximal tubule of the rat kidney. The model represents compliant S1, S2, and S3 segments and accounts for their specific apical and basolateral transporters. Sodium is reabsorbed transcellularly, via apical Na+/H+ exchangers (NHE) and Na+-glucose (SGLT) cotransporters, and paracellularly. Our results suggest that TNa/QO2 is 80% higher in S3 than in S1–S2 segments, due to the greater contribution of the passive paracellular pathway to TNa in the former segment. Inhibition of NHE or Na-K-ATPase reduced TNa and QO2, as well as Na+ transport efficiency. SGLT2 inhibition also reduced proximal tubular TNa but increased QO2; these effects were relatively more pronounced in the S3 vs. the S1–S2 segments. Diabetes increased TNa and QO2 and reduced TNa/QO2, owing mostly to hyperfiltration. Since SGLT2 inhibition lowers diabetic hyperfiltration, the net effect on TNa, QO2, and Na+ transport efficiency in the proximal tubule will largely depend on the individual extent to which glomerular filtration rate is lowered.

The effect of sodium taurocholate on proximal tubular reabsorption in the rat kidney

1987 ◽  
Vol 72 (1) ◽  
pp. 139-141 ◽  
Author(s):  
O. S. Better ◽  
V. Guckian ◽  
G. Giebisch ◽  
R. Green
Keyword(s):  
Proximal Tubule ◽  
Bile Salts ◽  
Rat Kidney ◽  
Sodium Taurocholate ◽  
Tubular Reabsorption ◽  
Major Site ◽  
Proximal Tubular ◽  
Tubular Fluid Reabsorption ◽  
Proximal Tubular Reabsorption

1. Microperfusion of tubules in situ was used to study the direct effect of sodium taurocholate on reabsorption of fluid by the proximal tubule of the rat. 2. Sodium taurocholate (0.1 mmol/l) in the tubular perfusate reduced proximal tubular fluid reabsorption by approximately 30%. 3. Thus, the proximal tubule appears to be a major site at which bile salts cause a natriuresis in the rat, and possibly in obstructive jaundice in man.

scholarly journals Contractility and 45Ca fluxes in heart muscle of flounder at a lowered extracellular NaCl concentration

1984 ◽  
Vol 109 (1) ◽  
pp. 201-207
Author(s):  
H. Gesser ◽  
A. Mangor-Jensen
Keyword(s):  
Sodium Chloride ◽  
Positive Inotropic Effect ◽  
Chloride Concentration ◽  
Sodium Concentration ◽  
Free Solution ◽  
Observable Effect ◽  
Resting Tension ◽  
Nacl Concentration ◽  
Extracellular Sodium ◽  
45Ca Efflux

The twitch force of isolated electrically paced ventricular strips of flounder, Platichthys flesus L., increased after lowering the extracellular sodium chloride concentration by 50 mmol l-1. This response was markedly reduced by replacing the sodium chloride with either Tris-HCl or sucrose, so that osmolarity was unchanged. The 45Ca efflux decreased and the 45Ca influx increased when the extracellular sodium concentration Nao+ was lowered. In contrast, changing only the osmolarity had no observable effect on these fluxes. An increased resting tension appeared in strips exposed to a Na+-, Ca2+-free solution. This was transient at an unchanged osmolarity but became permanent at an osmolarity lowered by 100 mosmol l-1. These results suggest that both a lowered Nao and a lowered osmolarity have a positive inotropic effect, due respectively to an increased cellular uptake of Ca2+ and a redistribution of cellular Ca2+.

Chloride transport by rat renal proximal tubule: effects of bicarbonate absorption

1986 ◽  
Vol 250 (6) ◽  
pp. F1046-F1054
Author(s):  
K. Bomsztyk
Keyword(s):  
Proximal Tubule ◽  
Chloride Transport ◽  
Rat Kidney ◽  
Ionic Composition ◽  
Chloride Concentration ◽  
Low Ph ◽  
Sodium Absorption ◽  
Metabolic Inhibitor ◽  
Chloride Absorption

In the early part of the proximal tubule chloride concentration is increased above that in plasma, a change attributed to preferential absorption of bicarbonate with sodium and water. To determine the mechanism(s) of the preferential absorption of HCO3 over chloride, in vivo paired perfusions were done in surface proximal tubules of the rat kidney. Each tubule was perfused with a control bicarbonate solution, similar in ionic composition to the solution normally present in the early part of the proximal tubule, and one of the experimental solutions that were modified by either replacing all of bicarbonate with sulfate, N-2-hydroxyethylpiperazine-N'-ethanesulfonate (HEPES), or all bicarbonate with sulfate and sodium with lithium, or addition of acetazolamide (ATZ), or cyanide (CN). Sufficient mannitol was added to reduce net fluid flux to zero. When sulfate replaced bicarbonate in luminal fluid, net chloride absorption was enhanced, a change associated with low lumen HCO3 and low pH. ATZ inhibited HCO3 absorption, whereas net Cl absorption increased, an effect associated with high HCO3 and low pH. With HEPES-plus-ATZ solutions, chloride absorption also increased but, in contrast to SO4 or ATZ solutions, pH increased. With sulfate and lithium replacement chloride absorption also increased despite net sodium secretion. CN, a metabolic inhibitor, inhibited HCO3 and sodium absorption but stimulated net chloride absorption. The data indicate that HCO3 absorption inhibits chloride absorption, a process independent of luminal HCO3 per se, luminal pH, sodium absorption, and transepithelial volume flux and voltage.

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