Hypocalcemia-associated modulation of renal response to acute volume expansion in rats

1987 ◽  
Vol 253 (4) ◽  
pp. F726-F733
Author(s):  
D. E. Wesson
Keyword(s):  
Body Weight ◽  
Proximal Tubule ◽  
Volume Expansion ◽  
Wistar Rats ◽  
Prostaglandin Synthesis ◽  
Free Flow ◽  
Renal Response ◽  
Clearance Studies ◽  
Chloride Excretion ◽  
Filtered Load

The present study used free-flow micropuncture and whole-kidney clearance studies to determine the renal response to normocalcemic vs. hypocalcemic acute volume expansion (AVE) in anesthetized Munich-Wistar rats. Animals received AVE with Ringer bicarbonate to 10% body weight; half of these animals were supplemented with calcium to maintain normocalcemia (VE + Ca2+) and half were allowed to become hypocalcemic (VE). Filtered load of chloride and total CO2 (TCO2) to the superficial proximal tubule and delivered load to the superficial loop segment were not different between groups. Superficial proximal tubule absolute Cl reabsorption was not different, but superficial loop segment absolute Cl reabsorption was less in the VE + Ca2+ animals (2,221+/- 106 vs. 2,651+/- 125 pmol/min, P less than 0.05) and whole-kidney fractional chloride excretion was greater (10.5+/- 1.6 vs. 4.3+/- 0.5%, P less than 0.05). When indomethacin (I) was administered to hypocalcemic (VE + I) and normocalcemic (VE + Ca2+ + I) AVE animals, both groups of animals had tubular and whole-kidney chloride reabsorption similar to VE animals. TCO2 reabsorption was not influenced by Ca2+ or I. The data indicate that normocalcemic vs. hypocalcemic AVE results in reduced superficial loop segment chloride reabsorption and greater whole-kidney fractional chloride excretion in the absence but not in the presence of prostaglandin inhibition. The data are compatible with an effect of hypocalcemia during AVE to limit superficial loop segment and whole-kidney chloride excretion by inhibiting renal prostaglandin synthesis.

RENAL RESPONSE TO INFUSION OF ISOTONIC RINGER-LOCKE SOLUTION: EFFECT OF HYPOPHYSECTOMY

1977 ◽  
Vol 74 (2) ◽  
pp. 193-204
Author(s):  
J. T. BAKER ◽  
S. SOLOMON
Keyword(s):  
Body Weight ◽  
Proximal Tubule ◽  
Volume Expansion ◽  
Extracellular Fluid ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Water Reabsorption ◽  
Locke Solution ◽  
Hypophysectomized Rats ◽  
Distal Tubules

A comparison of the renal response to extracellular fluid volume expansion (5% body weight) was made between 25 normal and 25 chronically hypophysectomized rats. The extracellular fluid compartments averaged 25 ± 1% of body weight in both groups during control, fasted conditions. Extracellular fluid volume increased to 33 ± 1% in hypophysectomized and 34 ± 2% in normal rats during expansion, based on body weight. In addition, filtration fraction was similar in both normal and hypophysectomized rats during control (0·29 ± 0·03 and 0·26 ± 0·02 respectively) and infusion of Ringer–Locke solution (0·24 ± 0·05 and 0·27 ± 0·05 respectively). Thus our results cannot be explained by differences in the degree of expansion or failure to increase filtration in proportion to plasma flow. During infusion of isotonic Ringer–Locke solution, fractional water and sodium excretion both averaged 5·1% in normal rats and only 1·3% and 0·82% respectively in hypophysectomized rats. The ratio of single nephron to whole kidney filtration rate failed to increase as much in hypophysectomized compared with normal rats. Significant increases of fractional volume excretion occurred in both groups by the end of the accessible portion of the proximal tubule. However, fractional water reabsorption was depressed significantly more in normal (mean = 37%) than in hypophysectomized rats (mean = 19%). Fractional water reabsorption in distal tubules was similar in both groups during expansion. Arterial pressure was lower in hypophysectomized rats under control conditions, but showed similar changes during expansion compared with normal rats. Passage time decreased significantly in all groups after Ringer–Locke infusion, but remained prolonged in hypophysectomized rats in proximal and distal tubules. It is concluded that chronic hypophysectomy results in a less efficient renal excretion of volume and sodium chloride load. This inefficiency appears to be related in part to (1) failure of the proximal tubule to depress water reabsorption to a level equivalent to normal rats, and (2) failure to re-distribute flow to outer cortical glomeruli following extracellular fluid volume expansion in hypophysectomized rats.

Axial heterogeneity in the rat proximal convoluted tubule. I. Bicarbonate, chloride, and water transport

1984 ◽  
Vol 247 (5) ◽  
pp. F816-F821 ◽  
Author(s):  
F. Y. Liu ◽  
M. G. Cogan
Keyword(s):  
Proximal Tubule ◽  
Water Transport ◽  
Wistar Rats ◽  
Proximal Convoluted Tubule ◽  
Free Flow ◽  
Concentration Profiles ◽  
Transport Capacity ◽  
Water Reabsorption ◽  
Substrate Concentrations

To measure simultaneously the concentration profiles of bicarbonate, chloride and inulin along the length of the superficial proximal convoluted tubule, free-flow micropuncture measurements were made sequentially from the end-proximal tubule to Bowman's space in 10 tubules of hydropenic Munich-Wistar rats. Bicarbonate and volume reabsorption were 354 +/- 21 pmol X mm-1 X min-1 and 5.9 +/- 0.4 nl X mm-1 X min-1 in the first millimeter and fell progressively in the remaining 3.8 mm of tubule, averaging 83 +/- 4 pmol X mm-1 X min-1 and 2.3 +/- 0.5 nl X mm-1 X min-1, respectively. The values in the initial millimeter represents a high transport capacity since they exceed rates that have been observed when comparable or even higher mean luminal substrate concentrations were presented to the late proximal tubule. In contrast, chloride reabsorption was only 206 +/- 55 peq X mm-1 X min-1 in the first millimeter compared with a mean of 306 +/- 22 peq X mm-1 X min-1 in the rest of the tubule. In conclusion, there is substantial axial transport heterogeneity, with bicarbonate and water reabsorption higher but chloride reabsorption lower in the early compared with the late superficial proximal convoluted tubule.

Effect of volume expansion with NaCl or NaHCO3 on nephron fluid and Cl transport

1977 ◽  
Vol 233 (2) ◽  
pp. F118-F125
Author(s):  
J. H. Galla ◽  
J. E. Beaumont ◽  
R. G. Luke
Keyword(s):  
Proximal Tubule ◽  
Plasma Volume ◽  
Sodium Excretion ◽  
Volume Expansion ◽  
Chloride Transport ◽  
Loop Of Henle ◽  
Fluid Reabsorption ◽  
Micropuncture Technique ◽  
Chloride Excretion ◽  
Anion Composition

To assess the influence of plasma anions on nephron fluid and chloride transport following volume expansion (VE), rats were studied by micropuncture technique during hydropenia and after VE with NaCl (CVE) or NaHCO3 (BVE). VE with either solution produced increments in plasma volume, SNGFR, and fractional sodium excretion (FENa), and decrements in proximal and distal TF/P inulin ratio which were not different. The proximal transepithelial chloride ratio decreased similarly in CVE (from 1.34 to 1.16) and BVE (from 1.32 to 1.17). Following VE, proximal fractional Cl reabsorption decreased similarly in both CVE (-5.9%) and BVE (-7.4%). Early distal fractional Cl reabsorption also was decreased in CVE (-12%) but not in BVE (-1%). Fractional chloride excretion increased in CVE but not in BVE. Therefore, following VE plasma anion composition did not significantly modify either fluid reabsorption in proximal tubule or loop of Henle or urinary Na excretion. The fraction of sodium reabsorbed with chloride in the proximal tubule increased, and Cl conservation, primarily within the loop of Henle, can be maintained despite marked natriuresis.

Depressed distal tubule acidification corrects chloride-deplete alkalosis in rats

1990 ◽  
Vol 259 (4) ◽  
pp. F636-F644 ◽  
Author(s):  
D. E. Wesson
Keyword(s):  
Linear Regression ◽  
Proximal Tubule ◽  
Metabolic Alkalosis ◽  
Wistar Rats ◽  
Distal Tubule ◽  
Bicarbonate Reabsorption ◽  
Dependent Relationship ◽  
Distal Tubules ◽  
Lower Slope ◽  
Filtered Load

We investigated the relative contributions made by the proximal and distal tubule to the correction of Cl-deplete metabolic alkalosis induced by systemic administration of NaCl. Free-flow micropuncture was used to examine net bicarbonate reabsorption in superficial proximal and distal tubules of anesthetized Munich-Wistar rats during maintenance and correction of chronic furosemide-induced Cl-deplete metabolic alkalosis. The distal tubule of animals with correcting vs. maintained alkalosis had a lower fractional reabsorption of bicarbonate (38 vs. 75%, P less than 0.001) and a lower slope of the linear regression comparing absorption to delivered load (0.48 vs. 0.99, P less than 0.02). By contrast, proximal tubule of animals with correcting vs. maintained alkalosis had fractional reabsorption (85 vs. 90%, P = 0.07) and slopes of the regression comparing reabsorption to filtered load (1.09 vs. 0.98, P = 0.48) that were not different. The data indicate that correction of Cl-deplete metabolic alkalosis induced by NaCl administration involves a qualitative decreased in bicarbonate reabsorption in distal tubule with maintenance of the same load-dependent relationship for bicarbonate reabsorption in proximal tubule.

Dose-dependent and time-dependent metabolic, hemodynamic, and redox disturbances in dexamethasone-treated Wistar rats

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Elvine P. Nguelefack-Mbuyo ◽  
Fernande P. Peyembouo ◽  
Christian K. Fofié ◽  
Télesphore B. Nguelefack
Keyword(s):  
Insulin Resistance ◽  
Body Weight ◽  
Catalase Activity ◽  
Wistar Rats ◽  
Chronic Treatment ◽  
Body Weight Loss ◽  
Redox Status ◽  
Duration Of Treatment ◽  
Renal Hypertrophy ◽  
Subchronic Treatment

Abstract Objectives Dexamethasone is used experimentally to induce insulin resistance and type 2 diabetes. However, data concerning the dose, the duration of treatment, and the associated comorbidities are inconsistent. The aim of this study was to compare the effects of different doses of dexamethasone and the duration of treatment necessary for the development of a model of insulin resistance that mimics the clinical condition with the associated comorbidities. Methods Dexamethasone was administered intramuscularly to male Wistar rats, at doses of 500 and 1,000 µg/kg/day for the subchronic treatment (eight consecutive days) and at doses of 5, 25, 50, and 100 µg/kg/day in chronic treatment (28 consecutive days). Effects on body weight, metabolism, hemodynamics, renal function, and redox status were evaluated. Results Both treatments induced a progressive body weight loss that was drastic in subchronic treatment, improved glucose tolerance without affecting fasting glycemia. Doses of 1,000 and 100 µg/kg were associated with hypertriglyceridemia, hypertension, and increased heart rate, cardiac and renal hypertrophy. Increased creatinemia associated with reduced creatinuria were observed in sub-chronic treatment while increased proteinuria and reduced creatinuria were noticed in chronic treatment. 1,000 µg/kg dexamethasone caused an increase in hepatic, and renal malondialdehyde (MDA) and glutathione (GSH) coupled with a reduction in catalase activity. The dose of 100 µg/kg induced a rise in GSH and catalase activity but reduced MDA levels in the kidney. Conclusions Doses of 1,000 µg/kg for subchronic and 100 µg/kg for chronic treatment exhibited similar effects and are the best doses to respective time frames to induce the model.

scholarly journals AT II Receptor Blockade and Renal Denervation: Different Interventions with Comparable Renal Effects?

2021 ◽  
pp. 1-11
Author(s):  
Kristina Rodionova ◽  
Martin Hindermann ◽  
Karl Hilgers ◽  
Christian Ott ◽  
Roland E. Schmieder ◽  
...  
Keyword(s):  
Body Weight ◽  
Volume Expansion ◽  
Neural Control ◽  
Renal Denervation ◽  
Urine Volume ◽  
Receptor Blockade ◽  
Ang Ii ◽  
Water Excretion ◽  
Arterial Blood ◽  
Renal Sympathetic

<b><i>Background:</i></b> Angiotensin II (Ang II) and the renal sympathetic nervous system exert a strong influence on renal sodium and water excretion. We tested the hypothesis that already low doses of an Ang II inhibitor (candesartan) will result in similar effects on tubular sodium and water reabsorption in congestive heart failure (CHF) as seen after renal denervation (DNX). <b><i>Methods:</i></b> Measurement of arterial blood pressure, heart rate (HR), renal sympathetic nerve activity (RSNA), glomerular filtration rate (GFR), renal plasma flow (RPF), urine volume, and urinary sodium. To assess neural control of volume homeostasis, 21 days after the induction of CHF via myocardial infarction rats underwent volume expansion (0.9% NaCL; 10% body weight) to decrease RSNA. CHF rat and controls with or without DNX or pretreated with the Ang II type-1 receptor antagonist candesartan (0.5 ug i.v.) were studied. <b><i>Results:</i></b> CHF rats excreted only 68 + 10.2% of the volume load (10% body weight) in 90 min. CHF rats pretreated with candesartan or after DNX excreted from 92 to 103% like controls. Decreases of RSNA induced by volume expansion were impaired in CHF rats but unaffected by candesartan pointing to an intrarenal drug effect. GFR and RPF were not significantly different in controls or CHF. <b><i>Conclusion:</i></b> The prominent function of increased RSNA – retaining salt and water – could no longer be observed after renal Ang II receptor blockade in CHF rats.

Nephrotoxicity of Cyclosporin a and Contrast Media

1989 ◽  
Vol 30 (6) ◽  
pp. 647-653 ◽  
Author(s):  
H. S. Thomsen ◽  
S. Larsen ◽  
P. Skaarup ◽  
L. Hemmingsen ◽  
H. Dieperink ◽  
...  
Keyword(s):  
Body Weight ◽  
Contrast Media ◽  
Light Microscopy ◽  
Cyclosporin A ◽  
Contrast Medium ◽  
Intravenous Injection ◽  
Wistar Rats ◽  
Peroral Administration ◽  
Albumin Excretion

Urine profiles (albumin, glucose, NAG, LDH, GGT and sodium) were followed for 22 h or 8 days after intravenous injection of diatrizoate, iohexol or saline in 30 adult Wistar rats in which nephrotoxicity was induced by daily peroral administration of 25 mg/kg body weight cyclosporin A over a 14-day period. Another 10 rats which had the vehicle of the cyclosporin A solution (placebo) and saline injected intravenously served as controls. The effect of iohexol and saline on the albumin excretion was similar, whereas diatrizoate increased it significantly. Both contrast media caused significantly increased excretion of all three enzymes. The contrast media had no effect on the excretion of glucose and sodium. Except for the fact that the excretion of NAG was significantly higher following iohexol than following diatrizoate 24 to 46 h after injection no significant differences between the two media were found from 24 h after injection among the rats given cyclosporin A. No contrast medium related changes were found by light microscopy of the kidneys. Neither iohexol nor diatrizoate potentiate acute cyclosporin A nephrotoxcity.

scholarly journals Regression of gestational diabetes induced cardiomegaly in offspring of diabetic rat

2009 ◽  
Vol 24 (4) ◽  
pp. 251-255 ◽  
Author(s):  
Honório Sampaio Menezes ◽  
Cláudio Galeano Zettler ◽  
Alice Calone ◽  
Jackson Borges Corrêa ◽  
Carla Bartuscheck ◽  
...  
Keyword(s):  
Body Weight ◽  
Wistar Rats ◽  
Weight Ratio ◽  
Diabetic Rats ◽  
Heart Weight ◽  
Diabetic Rat ◽  
Control Group ◽  
Computer Assisted ◽  
Significant Difference ◽  
Levene Test

PURPOSE: To compare body weight and length, heart weight and length, heart-to-body weight ratio, glycemia, and morphometric cellular data of offspring of diabetic rats (ODR) and of normal rats (control). METHODS: Diabetes was induced in 3 pregnant Wistar rats, bearing 30 rats, on the 11th day after conception by intraperitoneal injection of 50 mg/kg of streptozotocin. Six normal pregnant Wistar rats, bearing 50 rats, made up the control group. Morphometric data were obtained using a scale for the weight, length, heart and body measurements. Morphometric cellular data were obtained by a computer assisted method applied to the measurements of myocytes. Statistical analysis utilized Student's t-test, ANOVA and Levene test. RESULTS: Control offspring had greater mean body weight and length than offspring of diabetic rats (p < 0.001). Heart weight and length and heart-to-body ratios of newborn rats differed between groups at birth (p < 0.001), but showed no difference at 21 days. Mean nuclei area and perimetric value of the myocytes decrees throughout the first 21 days of life (p < 0.01) in the diabetic group. CONCLUSIONS: Heart hypertrophy on the offspring of diabetic rats at birth was demonstrated by the significant difference between the groups. After the eleventh day, no difference was found, which confirmed regression of cardiomegaly. The significant difference between the first and the 21th day of life, for nuclei area feature, demonstrate regression of cardiac hypertrophy in the offspring of diabetic rats.

scholarly journals Effects of proportional high-protein/low-carbohydrate formulated diet consumption in diabetic rats: Beneficial impact on glycemic and weight control

2020 ◽  
Vol 20 (07) ◽  
pp. 16984-16996
Author(s):  
MMC Anyakudo ◽  
◽  
DO Adeniji ◽  
Keyword(s):  
Body Weight ◽  
Wistar Rats ◽  
Treated Group ◽  
Morphological Features ◽  
High Protein ◽  
Control Group ◽  
Formulated Diet ◽  
Low Carbohydrate ◽  
Male Wistar Rats ◽  
And Control

The metabolic response to nutrient ingestion and the rate of digestion and absorption of nutrient molecules in bowel physiology plays an important role in the metabolic control of some human chronic non-infectious diseases. This experimentally-controlled designed nutritional study which lasted eight weeks aimed to determine the effects of proportional high-protein/low-carbohydrate (HP/LC) formulated diet on glycemic tolerance, glycemic control, body weight, organ weight and organ morphometry in healthy and diabetic adult male Wistar rats. Twenty-four male Wistar rats purchased from a disease-free stock were randomly categorized into four groups (n = 6, each) after two weeks acclimatization period in raised stainless steel cages with 6 mm2mesh floor and replaceable numbered blotters papers placed under each cage in a well-ventilated animal house. Animal groups include: Healthy control group (HC), Healthy treated group (HT), Diabetic control group (DC) and Diabetic treated group (DT. The animals were fed according to the experimental design with water ad libitumfor eight weeks. Diabetes was inducted with freshly prepared alloxan monohydrate solution (150 mg/kg bw, intraperitoneally). Body weights and fasting blood sugar concentrations were measured twice weekly, while oral glucose tolerance test was conducted on the last day of the eighth-week study and subsequently followed by organs extraction after anesthesia for weight and gross assessment. Proportional high-protein/low-carbohydrate formulated diet caused significant reduction in mean body weight of treated diabetic (DT: 22.6%; P= .001) and healthy (HT: 5.8%; P= .007) rats while the control animals on control diet recorded significant (P< .05) increase in body weight gain (DC: 12.4%; HC: 11.2%). Glycemic tolerance and control improved significantly in diabetic treated rats over that of the healthy treated rats. Gross morphometry of the extracted organs (kidneys, liver, heart, lungs, spleen and testes) revealed sustained normal morphological features without any visible lesion. In conclusion, consumption of proportional high-protein/low-carbohydrate formulated diet enhanced body weight reduction and sustained normal organ morphological features with good glycemic tolerance and control in experimental rats, suggesting its dietary potentiality, safety and suitability to ameliorate obesity-related diabetes.

scholarly journals Effects of aqueous leaf extract of Corchorus olitorius on the testis and blood testosterone level of adult Wistar rats

2021 ◽  
Vol 10 (2) ◽  
pp. 024-030
Author(s):  
Godwin Chinedu Uloneme ◽  
Demian Nnabuihe Ezejindu ◽  
Darlington Cyprian Akukwu ◽  
Amadi Chibundu Chiekezie
Keyword(s):  
Body Weight ◽  
Wistar Rats ◽  
Day Treatment ◽  
Control Group ◽  
Corchorus Olitorius ◽  
Group A ◽  
Normal Rat ◽  
Group B ◽  
Calcium Iron ◽  
Group D

Background: The extract of Corchorus olitorius has a reasonable content of vitamins A and C, calcium, iron and fibre, and therefore enjoys a universal application in the treatment of some disease conditions, even as the whole leaf is a very important component of food in so many cultures. Purpose: The study was designed to investigate the effect of Corchorus olitorius extracts on the testis of adult Wistar rats. Method: A total number of thirty two adult Wistar rats weighing between 180 and 200 grammes separated into four groups labeled A,B,C and D respectively were used for the study. Animals in group A which served as the control group were fed with the normal rat chow and water only. The group B rats were administered 100mg/kg body weight of aqueous extract of Corchorus olitorus; while those in group C were administered 500mg/kg body weight of the extract. The group D rats received 1000mg/kg body weight of the extract. For a period of four weeks, the different experimental animal groups received the respective aforementioned treatments once daily, around nine- o’clock in the morning through oral intubation. At the end of the 28 day treatment, the animals were sacrificed and the testes harvested for histological, investigation, and through cardiac puncture, blood samples for some hormonal studies was also collected and investigated using standard laboratory standards. Results: Observations made showed that the extract produced no histological distortions, degenerative or defective effects on the testicular tissues. The testosterone levels of group B, C, and D rats were observed to be significantly higher (P<0.005) than that of the group A (control group).ound: The extract of Corchorus olitorius has a reasonable content of vitamins A and C, calcium, iron and fibre, and therefore enjoys a universal application in the treatment of some disease conditions, even as the whole leaf is a very important component of food in so many cultures. Purpose: The study was designed to investigate the effect of Corchorus olitorius extracts on the testis of adult Wistar rats. Method: A total number of thirty two adult Wistar rats weighing between 180 and 200 grammes separated into four groups labeled A,B,C and D respectively were used for the study. Animals in group A which served as the control group were fed with the normal rat chow and water only. The group B rats were administered 100mg/kg body weight of aqueous extract of Corchorus olitorus; while those in group C were administered 500mg/kg body weight of the extract. The group D rats received 1000mg/kg body weight of the extract. For a period of four weeks, the different experimental animal groups received the respective aforementioned treatments once daily, around nine- o’clock in the morning through oral intubation. At the end of the 28 day treatment, the animals were sacrificed and the testes harvested for histological, investigation, and through cardiac puncture, blood samples for some hormonal studies was also collected and investigated using standard laboratory standards. Results: Observations made showed that the extract produced no histological distortions, degenerative or defective effects on the testicular tissues. The testosterone levels of group B, C, and D rats were observed to be significantly higher (P<0.005) than that of the group A (control group).

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