scholarly journals Effects of intraruminal sodium chloride infusion on rumen and renal nitrogen and electrolyte dynamics in sheep

1986 ◽  
Vol 56 (2) ◽  
pp. 379-394 ◽  
Author(s):  
Ian R. Godwin ◽  
Vernon J. Williams
Keyword(s):  
Sodium Chloride ◽  
Food Intake ◽  
Turnover Rate ◽  
Volatile Fatty Acids ◽  
Renal Excretion ◽  
Renal Plasma Flow ◽  
Extracellular Fluid ◽  
Fractional Excretion ◽  
Water Excretion ◽  
Plasma Urea

1. Sheep were given 800 g low-protein roughage/d at 2 h intervals and infused intraruminally with 0, 500, 750, 1000, 1250, 1500 or 2000 mmol sodium chloride/d in 436 ml water. The digestibility of various food fractions and rumen ammonia, volatile fatty acids (VFA) and liquid turnover rate were measured, along with renal haemodynamics and the renal excretory patterns of nitrogen and electrolytes. Ad lib. food intake was determined during the infusion of 0 and 2000 mmol NaCl/d.2. Infusion of NaCl up to 750 mmol/d had virtually no effect on the indices measured, except water intake and water excretion. Infusion of greater amounts caused a step-wise decrease in the digestibility of organic matter (OM) and N. Rumen liquid turnover rate was increased substantially and rumen NH2, and VFA concentrations were decreased. Ad lib. food intake was not different when either 0 or 2000 mmol NaCl/d were infused into the rumen.3. The glomerular filtration rate and effective renal plasma flow (ERPF) were substantially increased after the infusion of 1250 mmol or more NaCl/d. Extracellular fluid volume was also increased. The renal excretion of urea and uric acid+allantoin (URAL) were decreased at the higher infusion rates but the fractional excretions of both these substances were enhanced. The excretion of sodium, chloride, calcium and magnesium were markedly increased with increasing salt infusion.4. The results suggest that high NaCl inputs into the rumen increase the rumen turnover rate, which in turn decreases the digestibility of OM, particularly N. This causes lower rumen NH3, and VFA concentrations. Plasma urea and URAL concentrations are also decreased and this causes lower renal excretion of these substances despite a much higher fractional excretion resulting from the greatly enhanced urine flow rate.5. When roughages low in N are given, NaCl intake should be kept below 20 mmol/kg body-weight per d to prevent a decline in the digestibility of the food and any consequent reduction in protein available to the sheep.

Effects of late pregnancy and early lactation on renal urea handling in Corriedale ewes

1998 ◽  
Vol 130 (2) ◽  
pp. 213-216 ◽  
Author(s):  
B. B. NDIBUALONJI ◽  
M.-N. RODRIGUEZ ◽  
D. DEHARENG ◽  
A. CIRIO ◽  
J.-M. GODEAU
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Late Pregnancy ◽  
Fractional Excretion ◽  
Urine Osmolality ◽  
Early Lactation ◽  
Plasma Urea

The aim of the study was to investigate the changes in renal function in late pregnant and early lactating Corriedale ewes. Compared with the non-productive state, plasma urea concentration was increased by 67% during pregnancy, whereas it decreased by 36% during lactation. Urine flow, urea clearance, renal plasma flow and glomerular filtration rate were significantly reduced (P<0·05) during both late pregnancy and early lactation. Filtered load of urea and the amount of urea eliminated were significantly reduced (P<0·05) only in lactating ewes. No changes were noted in the fractional excretion of urea, the filtration fraction and the urine osmolality during both late pregnancy and early lactation. It was concluded that, as in other breeds, Corriedale ewes can adapt to increased nitrogen requirements during late pregnancy, and especially during early lactation, by increasing the renal conservation of urea. Unlike other breeds, however, Corriedale ewes restrict the urine urea losses mainly by reducing renal plasma flow and glomerular filtration rate, without any modification of the tubular reabsorption of urea during both late pregnancy and early lactation.

Effect of infusion of pharmacologic amounts of vasopressin on renal electrolyte excretion

1975 ◽  
Vol 228 (3) ◽  
pp. 890-894 ◽  
Author(s):  
NA Kurtzman ◽  
PW Rogers ◽  
S Boonjarern ◽  
JA Arruda
Keyword(s):  
Renal Plasma Flow ◽  
Fractional Excretion ◽  
Sodium Reabsorption ◽  
Water Excretion ◽  
Bicarbonate Reabsorption ◽  
Ion Secretion ◽  
Radioactive Microsphere ◽  
Glucose Reabsorption ◽  
Inner Cortex ◽  
Sodium Clearance

Aqueous vasopressin was infused to bicarbonate- and glucose-loaded dogs and to nonloaded antidiuretic dogs in doses of 50 mU/kg per min or 50 mU/kg per h. Both doses caused a marked increase in sodium, chloride, and water excretion. The larger dose raised the fractional excretion (sodium clearance (C-Na)/glomerular filtration rate (GFR) times 100) of these ions from 2% or less to in excess of 20%. Blocking the pressor effects of these doses of vasopressin with sodium nitroprusside did not alter the marked natriuretic and chloriuretic effect. The maximal rate of bicarbonate and glucose reabsorption was not depressed by vasopressin infusion; fractional phosphate excretion, however, was markedly increased. Inhibiting distal hydrogen ion secretion by inducing selective aldosterone deficiency failed to uncover a vasopressin-induced inhibition of proximal bicarbonate reabsorption that might have been masked by increased distal bicarbonate reabsorption. There was no significant change in GFR, renal plasma flow, or filtration fraction. The distribution of cortical renal blood flow (measured by the radioactive microsphere technique) shifted toward the inner cortex after vasopressin administration. Vasopressin, in pharmacologic doses, is a potent diuretic that most likely exerts this effect by directly inhibiting sodium reabsorption at a point in the nephron distal to the proximal tubule.

Influence of oxytocin on renal hemodynamics and electrolyte and water excretion

1986 ◽  
Vol 251 (2) ◽  
pp. F290-F296 ◽  
Author(s):  
K. P. Conrad ◽  
M. Gellai ◽  
W. G. North ◽  
H. Valtin
Keyword(s):  
Infusion Rate ◽  
Low Dose ◽  
Renal Plasma Flow ◽  
Plasma Concentrations ◽  
Free Water ◽  
Fractional Excretion ◽  
Urine Flow ◽  
Water Excretion ◽  
Fractional Excretion Of Sodium ◽  
Synthetic Oxytocin

We examined the renal effects of synthetic oxytocin (OT) in the presence and absence of vasopressin in conscious euvolemic rats. Both sexes of the Long-Evans (LE) and Brattleboro homozygous (DI) strains were used. OT infused intravenously at 0.25 and 2.5 ng X min-1 X 100 g body wt (BW)-1 resulted, respectively, in plasma concentrations of 30 +/- 6 and 265 +/- 88 pg/ml in LE rats and 46 +/- 5 and 327 +/- 29 pg/ml in DI rats. Glomerular filtration rate (GFR) was augmented most consistently by the larger dose of hormone in LE rats (P less than 0.05), whereas the low infusion rate of OT enhanced GFR in DI rats (P less than 0.01). Effective renal plasma flow was not changed significantly. OT (both doses) increased the fractional excretion of sodium two- to threefold in each strain of animal (all at least P less than 0.05 from control), whereas the fractional excretion of potassium was largely unaffected. In LE rats, a diuresis was observed with either infusion rate of hormone, accompanied by a rise in osmolar clearance (COsm). In contrast, there was no change of urine flow with the low dose of OT in DI rats, because COsm increased and the clearance of free water (CH2O) decreased proportionately. The higher infusion rate of OT promoted antidiuresis in DI rats, with negative CH2O and little change in COsm. We conclude that oxytocin enhances GFR and is natriuretic regardless of the presence or absence of endogenous vasopressin.(ABSTRACT TRUNCATED AT 250 WORDS)

Water and electrolyte changes in tropical Merino sheep exposed to dehydration during summer

1961 ◽  
Vol 12 (5) ◽  
pp. 889 ◽  
Author(s):  
WV Macfarlane ◽  
RJH Morris ◽  
B Howard ◽  
J McDonald ◽  
OE Budtz-Olsen
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Water Conservation ◽  
Renal Plasma Flow ◽  
Extracellular Volume ◽  
Urine Volume ◽  
Extracellular Fluid ◽  
Initial Increase ◽  
Fluid Loss ◽  
Plasma Urea

During three summers field studies were made of Merino wethers deprived of water while exposed to sun and to maximum air temperatures ranging from 84°F (29°C) to 10S°F (42°C) at Julia Creek, lat. 21° S. Evaporative cooling determined the rate and extent of water and electrolyte changes and produced a different pattern each year. Control of body temperature failed when 31% of body weight was lost by the end of 10 days without water. In hotter weather 5 days without water caused a 25% loss of body weight and in some sheep irreversible circulatory failure. In the course of dehydration, after an initial increase, the plasma and extracellular volume decreased up to 45% while concentrations of haemoglobin and plasma protein increased by 60%. In the plasma, potassium and sodium concentration increased less than that of haemoglobin. When 25% or more of weight was lost, plasma urea concentration rose to 136 mg/100 ml. Plasma osmolarity in some sheep reached 490 m-osmoles/l after 10 days. Urine volume fell after 2 days without water, and in a hot season less than 100 ml/24 hr was passed on the fourth or subsequent days. Concentrations increased over the first 4 or 5 days, reaching a maximum of 3.8 osmoles/l, then declined. Between half and two-thirds of the osmolarity was accountable to sodium and potassium salts. In rapid dehydration, more sodium was excreted than potassium. There was reduced sodium excretion when water was ingested after dehydration. Renal function studies in ewes indicated that filtration, renal plasma flow, and glucose reabsorption were reduced to half after 5 days without water in the heat. The chance of survival in dehydration appears to be increased by low rates of water loss in the first 3 days, together with high sodium and low potassium excretion. A full rumen, containing water up to 13% of body weight, could provide all the extracellular fluid loss. More than half of the weight loss appears, however, to come from intracellular sources. Extracellular fluid was drawn upon to a greater extent when the rate of dehydration was rapid, than in the cooler periods of slow weight loss. Survival in the sun without water depends upon insulation, water conservation, water reserves in rumen and extracellular fluid, the ability to adjust electrolyte concentrations, and the ability to maintain circulation with lowered plasma volume.

Renal effects of nitric oxide synthesis inhibition in cirrhotic rats

1994 ◽  
Vol 267 (6) ◽  
pp. R1454-R1460 ◽  
Author(s):  
N. M. Atucha ◽  
J. Garcia-Estan ◽  
A. Ramirez ◽  
M. C. Perez ◽  
T. Quesada ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Renal Excretion ◽  
Renal Plasma Flow ◽  
Tubular Reabsorption ◽  
Nitric Oxide Synthesis ◽  
Important Mediator ◽  
Experimental Liver Cirrhosis ◽  
Endogenous Nitric Oxide ◽  
And Control ◽  
Experimental Liver

In the present study, we have characterized the renal response to inhibition of endogenous nitric oxide (NO) synthesis [intravenous NG-nitro-L-arginine methyl ester (L-NAME) for 3 h] in anesthetized cirrhotic rats, with (ASC) and without (CIR) ascites, at doses that do not change blood pressure (BP). Administration of L-NAME induced opposite effects on water (UV) and sodium (UNaV) excretion in cirrhotic and control animals. Infusion of 1 microgram.kg-1.min-1 of L-NAME in CIR (n = 5) decreased renal plasma flow (RPF) at the end of the 3-h period, whereas UV, UNaV, and glomerular filtration rate (GFR) were unaltered. In contrast, infusion of L-NAME at 10 micrograms.kg-1.min-1 in six more CIR increased UV and UNaV significantly by the 1st h, without changes in BP or GFR, and these parameters remained elevated throughout the experiment. Infusion of 1 microgram.kg-1.min-1 in ASC (n = 6) did not change BP or GFR but significantly enhanced UV and UNaV after the 1st h. These effects were prevented by pretreatment with L-arginine (0.1 mg.kg-1.min-1) in another group of ASC infused with 1 microgram.kg-1.min-1 of L-NAME. These results indicate that, in ASC and CIR cirrhotic rats, inhibition of NO synthesis at nonpressor does improves renal excretion of sodium and water via a decrease in tubular reabsorption. NO is an important mediator of the renal excretory and hemodynamic alterations of experimental liver cirrhosis.

TOTAL BODY CHLORIDE IN TUBERCULOUS MENINGITIS

PEDIATRICS ◽  
1954 ◽  
Vol 14 (2) ◽  
pp. 87-92
Author(s):  
DONALD B. CHEEK
Keyword(s):  
Tuberculous Meningitis ◽  
Metabolic Alkalosis ◽  
Extracellular Fluid ◽  
Fluid Restriction ◽  
Potassium Depletion ◽  
Water Excretion ◽  
Serum Chloride ◽  
The Status ◽  
Total Body

Seven children with tuberculous meningitis have been studied. In the absence of fluid restriction and vomiting, hypotonic expansion of the extracellular fluid has been revealed. This draws attention to an alteration in water excretion. Metabolic alkalosis yields evidence of cell potassium depletion. The serum chloride is no indication as to the status of total body chloride.

Sodium and Water Excretion in Nephrotic Patients: Effects of Changes in Renal Haemodynamics

1990 ◽  
Vol 79 (2) ◽  
pp. 123-129 ◽  
Author(s):  
Michael Allon ◽  
Charles B. Pasque ◽  
Mariano Rodriguez
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Urine Volume ◽  
Sodium Reabsorption ◽  
Plasma Volume Expansion ◽  
Water Excretion ◽  
Significant Change

1. Eight nephrotic patients were studied in order to evaluate the effects of acute changes in renal plasma flow and glomerular filtration rate on renal solute and water handling, in the absence of plasma volume expansion. 2. The subjects were studied first after the administration of captopril, a manoeuvre that increased renal plasma flow without a significant change in glomerular filtration rate, and a second time after receiving combined therapy with captopril and ibuprofen, a manoeuvre that decreased glomerular filtration rate without a significant change in renal plasma flow. 3. After captopril therapy, despite the increase in renal plasma flow, there was no significant change in proximal sodium reabsorption (as estimated from fractional lithium reabsorption), urine volume or urine osmolality. 4. The decrease in glomerular filtration rate observed after the administration of captopril plus ibuprofen was associated with decreases in fractional excretion of sodium and urine volume, and an increase in urine osmolality. The changes in these parameters of tubular function were proportionate to the changes in glomerular filtration rate. Fractional proximal sodium reabsorption increased substantially. 5. These observations suggest that, in the absence of plasma volume expansion, an increase in renal plasma flow does not increase sodium or water excretion by the nephrotic kidney. Moreover, during acute decreases in glomerular filtration rate, glomerulotubular balance appears to be disrupted, resulting in disproportionately high rates of proximal tubule sodium reabsorption.

Direct effects of endothelin in the rat kidney

1990 ◽  
Vol 258 (2) ◽  
pp. F397-F402 ◽  
Author(s):  
T. Katoh ◽  
H. Chang ◽  
S. Uchida ◽  
T. Okuda ◽  
K. Kurokawa
Keyword(s):  
Renal Artery ◽  
Rat Kidney ◽  
Renal Plasma Flow ◽  
Urine Volume ◽  
Fractional Excretion ◽  
Left Renal Artery ◽  
Dependent Manner ◽  
Direct Effects ◽  
Dose Dependent

In the present study, we tested the direct effects of endothelin (ET) on rat kidney in vivo. ET was infused into the left renal artery of anesthetized rats at a rate of 0.5, 5, 20, or 40 pmol/h. ET reduced ipsilateral urine volume (V), clearance of inulin (CIN), and clearance of p-aminohippuric acid (CPAH) in a dose-dependent manner. Thus ET at 20 pmol/h did not change V but decreased renal plasma flow (RPF) and glomerular filtration rate (GFR) by 27.6 +/- 14.3 and 30.8 +/- 10.4%, respectively, in the ipsilateral kidney. ET at 0.5 pmol/h was without effect and at 5 pmol/h had only minor effects on CIN and CPAH of ipsilateral kidney. At 40 pmol/h, ET reduced ipsilateral V, GFR, and RPF by 52.3 +/- 21.4, 58.4 +/- 14.5, and 72.5 +/- 10.6%, respectively. Filtration fraction and fractional excretion of Na remained unchanged during ET infusion. ET, 40 pmol/h, infused into the renal artery together with atrial natriuretic peptide (ANP) at a rate of 12 pmol/h reduced the ipsilateral V, GFR, and RPF by 33.2 +/- 6.3, 26.1 +/- 6.0, and 27.2 +/- 7.1%, respectively, decrements less than those with ET alone. When a calcium-channel blocker nicardipine was infused at a rate of 2.5 micrograms/h into the renal artery together with ET, 20 pmol/h, there was little change in the ipsilateral V, RPF, and GFR; ET, 40 pmol/h, with nicardipine did not change V and decreased GFR and RPF by 25.9 +/- 5.6 and 23.1 +/- 10.8%, respectively, decrements less than those without nicardipine.(ABSTRACT TRUNCATED AT 250 WORDS)

Decreased distal acidification in acute hypercapnia in the dog

1983 ◽  
Vol 244 (1) ◽  
pp. F19-F27
Author(s):  
H. J. Adrogue ◽  
B. J. Stinebaugh ◽  
A. Gougoux ◽  
G. Lemieux ◽  
P. Vinay ◽  
...  
Keyword(s):  
Extracellular Fluid ◽  
Respiratory Acidosis ◽  
Fractional Excretion ◽  
Distal Nephron ◽  
Sodium Potassium ◽  
Fractional Excretion Of Sodium ◽  
Dependent Component ◽  
Voltage Dependent ◽  
Bicarbonate Infusion

The present studies evaluate the effect of acute hypercapnia on distal nephron H+ secretion (DNH+S) in vivo by means of the urine-blood PCO2 difference (U-B PCO2) in alkaline urine. Bicarbonaturia was induced by either a sodium bicarbonate infusion or L-lysine administration. Our results demonstrate that the U-B PCO2, as a function of the urinary bicarbonate concentration, was significantly lower during acute respiratory acidosis; this effect was not dependent on changes in glomerular filtration rate and/or fractional excretion of sodium, potassium, and chloride. Infusion of the sodium salts of sulfate, a nonreabsorbable anion, did not correct the diminished U-B PCO2. Amiloride caused the U-B PCO2 to fall in normocapnic dogs but not in hypercapnic dogs. When hypercapnia was superimposed in dogs with extracellular fluid volume contraction, there were no changes in the U-B PCO2. This study indicates that acute hypercapnia in the intact dog decreases DNH+S and is compatible with an effect of hypercapnia on the voltage-dependent component of urine acidification. The mechanism appears to be direct rather than secondary to factors that influence the rate of sodium delivery to the distal nephron.

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