Unimpaired excretion of an acute salt load in conscious hypoproteinaemic dogs

1988 ◽  
Vol 75 (3) ◽  
pp. 271-276 ◽  
Author(s):  
J. A. Joles ◽  
H. A. Koomans ◽  
P. Boer ◽  
E. J. Dorhout Mees
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Protein ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Isotonic Saline ◽  
Fractional Excretion ◽  
Sodium Reabsorption ◽  
Filtration Fraction ◽  
Fractional Excretion Of Sodium

1. The role of hypoproteinaemia in the sodium retention seen in conditions such as the nephrotic syndrome is incompletely known. 2. To define the influence of severe hypoproteinaemia on kidney function, we studied the effect of an intravenous infusion of an isotonic saline load (133 mmol of sodium), as 1 litre of Ringer lactate solution, on sodium excretion and renal haemodynamics in conscious dogs before and after reduction of plasma protein from 68 ± 3 to 36 ±2 g/l by repeated plasmapheresis and a low protein diet. 3. During hypoproteinaemia, 2 days after a period of plasmapheresis, glomerular filtration rate and effective renal plasma flow were lower than in the control study. After the sodium load, both rose to values nearly identical with the pre-infusion levels found in normoproteinaemia, the filtration fraction remaining unchanged. This contrasted with the rise in filtration fraction after expansion in normoproteinaemia, where filtration fraction increased from 32 to 39% due to a rise in glomerular filtration rate. 4. After expansion, natriuresis rose to similar levels in normoproteinaemia (0.18 ±0.06 mmol/min) and hypoproteinaemia (0.20 ± 0.06 mmol/min), and increments in fractional excretion of sodium, potassium and chloride were also similar. However, baseline excretion was higher in the hypoproteinaemic dogs due to their overhydrated condition in this period immediately after plasmapheresis. 5. The fractional excretion of lithium, an alleged marker of proximal tubular sodium reabsorption, rose to comparable levels. 6. Hence, both the increase in filtration and decrease in reabsorption of sodium after an isotonic saline load are not affected by severe reduction in plasma protein concentration. Apparently, the pathways to augment natriuresis after acute expansion function normally in hypoproteinaemia.

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.

Supersensitivity to norepinephrine in chronically denervated kidneys: evidence for a postsynaptic effect

1987 ◽  
Vol 65 (11) ◽  
pp. 2219-2224 ◽  
Author(s):  
J. Krayacich ◽  
R. L. Kline ◽  
P. F. Mercer
Keyword(s):  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Renal Blood Flow ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Fractional Excretion ◽  
Urine Flow ◽  
Fractional Excretion Of Sodium ◽  
Infusion Of Norepinephrine

Denervation supersensitivity in chronically denervated kidneys increases renal responsiveness to increased plasma levels of norepinephrine. To determine whether this effect is caused by presynaptic (i.e., loss of uptake) or postsynaptic changes, we studied the effect of continuous infusion of norepinephrine (330 ng/min, i.v.) and methoxamine (4 μg/min, i.v.), an α1 adrenergic agonist that is not taken up by nerve terminals, on renal function of innervated and denervated kidneys. Ganglionic blockade was used to eliminate reflex adjustments in the innervated kidney and mean arterial pressure was maintained at preganglionic blockade levels by an infusion of arginine vasopressin. With renal perfusion pressure controlled there was a significantly greater decrease in renal blood flow (−67 ± 9 vs. −33 ± 8%), glomerular filtration rate (−60 ± 9 vs. −7 ± 20%), urine flow (−61 ± 7 vs. −24 ± 11%), sodium excretion (−51 ± 15 vs. −32 ± 21%), and fractional excretion of sodium (−50 ± 9 vs. −25 ± 15%) from the denervated kidneys compared with the innervated kidneys during the infusion of norepinephrine. During the infusion of methoxamine there was a significantly greater decrease from the denervated compared with the innervated kidneys in renal blood flow (−54 ± 10 vs. −30 ± 14%), glomerular filtration rate (−51 ± 11 vs. −19 ± 17%), urine flow (−55 ± 10 vs. −39 ± 10%), sodium excretion (−70 ± 9 vs. −59 ± 11%), and fractional excretion of sodium (−53 ± 10 vs. −41 ± 10%). These results suggest that vascular and tubular supersensitivity to norepinephrine in chronically denervated kidneys is due to postsynaptic changes involving α1-adrenergic receptors.

scholarly journals Tubular Secretion Markers, Glomerular Filtration Rate, Effective Renal Plasma Flow, and Filtration Fraction in Healthy Adolescents

2020 ◽  
Vol 2 (5) ◽  
pp. 670-672
Author(s):  
Jesse C. Seegmiller ◽  
Brian J. Wolfe ◽  
Nansy Albtoush ◽  
Isabella Melena ◽  
Susan P. Gross ◽  
...  
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Tubular Secretion ◽  
Effective Renal Plasma Flow ◽  
Filtration Fraction

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 Prolactin on Glomerular Filtration Rate

1978 ◽  
Vol 55 (4) ◽  
pp. 335-339 ◽  
Author(s):  
A. L. Riley ◽  
T. C. Hagen ◽  
J. E. Stefaniak
Keyword(s):  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Free Water ◽  
Flow Distribution ◽  
Fractional Excretion ◽  
Free Water Clearance ◽  
Fractional Excretion Of Sodium ◽  
Ovine Prolactin

1. The effect of infusion of ovine prolactin was studied in anaesthetized dogs pretreated with bromocryptine to reduce the release of endogenous prolactin. 2. Prolactin, injected intravenously and also directly into one kidney, resulted in a 12–18% increase in glomerular filtration rate (GFR) by both kidneys. 3. This increased GFR was not associated with any demonstrable changes in whole-kidney blood flow, distribution of intrarenal blood flow, fractional excretion of sodium or osmolar or free-water clearance. 4. We conclude that ovine prolactin produced an increase in GFR not dependent on an increase in whole-kidney plasma flow.

scholarly journals RENAL FUNCTION DURING CHRONIC ANEMIA IN MAN

Blood ◽  
1947 ◽  
Vol 2 (2) ◽  
pp. 192-202 ◽  
Author(s):  
STANLEY E. BRADLEY ◽  
GERALDINE P. BRADLEY
Keyword(s):  
Blood Flow ◽  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Normal Values ◽  
Renal Plasma Flow ◽  
Filtration Fraction ◽  
Chronic Anemia

Abstract 1. Renal function has been studied quantitatively in 15 patients with chronic anemia, 8 of whom were proved to have pernicious anemia. In 7 the anemia was secondary to chronic blood loss, iron deficiency, paroxysmal nocturnal hemoglobinuria, and leukemia. The effective renal plasma flow and glomerular filtration rate were measured by clearance technics; and tubular function, by saturation methods (diodrast Tm and glucose Tm). 2. The effective renal plasma flow, the glomerular filtration rate, and the filtration fraction (percentage of plasma filtered at the glomerulus) were reduced slightly below the normal values in most subjects. The effective renal whole blood flow was always greatly reduced, by 46 per cent on the average in males and by 31.8 per cent in females. 3. Since arterial pressure was not significantly depressed it was concluded that renal vasoconstriction occurs in chronic anemia, possibly as a homeostatic device for the diversion of blood to tissues more sensitive to oxygen lack. The relatively small reduction of filtration fraction implies afferent and efferent arteriolar vasoconstriction with dominance by the afferent arterioles. These changes were shown to be reversible, a return to normal values paralleling the return of the blood picture to normal. 4. Diodrast Tm was reduced significantly in 9 of 10 patients while the values of glucose Tm were normal in 6 of 7 patients. The normal values for glucose Tm indicated continued operation of all glomeruli and implied the absence of shunting or of cessation of blood flow in any significant portion of the kidney. The fall in diodrast Tm, which appeared to be reversible in 2 of 4 individuals, was interpreted as evidence of intracellular dysfunction rather than destruction or inactivation of nephrons.

scholarly journals Individual renal hemodymamic response to chronic angiotensin II receptor bloc­kade and the influence on the renin-angiotensin system gene polymorphisms

2010 ◽  
Vol 63 (9-10) ◽  
pp. 630-637
Author(s):  
Tamara Dragovic ◽  
Boris Ajdinovic ◽  
Vesna Ilic ◽  
Zvonko Magic ◽  
Zoran Andjelkovic ◽  
...  
Keyword(s):  
Glomerular Filtration Rate ◽  
Angiotensin Ii ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Filtration Fraction ◽  
Renal Vascular ◽  
Losartan Treatment

Introduction. Our study was aimed at determining whether the polymorphism of genes for different components of the renin-angiotensin-aldosterone system could influence the renal hemodynamic response to losartan treatment. Material and method. The study included 35 patients with type 1 diabetes mellitus and persistent albuminuria, genotyped for the 1166 A/C polymorphism gene for the angiotensin II type 1 receptor and I/D polymorphism of the angiotensin-converting enzyme gene. The participants were divided into groups according to the combinations of A or C allele: AA, AC, CC; and according to the combinations of I or D allele: II, ID and DD genotype. The patients received losartan therapy for 12 weeks. The renal hemodynamic measurements were determined at baseline and after the examination period. Results. Losartan therapy significantly reduced the filtration fraction from the baseline by 0.018?0.024 (p=0.012) only in the AC genotype. The glomerular filtration rate remained unchanged in all genotype groups. A significant increase in the effective renal plasma flow was obtained only in AC genotype (544?88 vs 575?90ml/min; p=0.02), while significant reductions in the renal vascular resistance were found in AA group (115?25 vs 95?21 mmHgx1-1xmin-1; p=0.001) and in AC group (118?30 vs 101?28 mmHgx1-1xmin-1; p=0.001). A significant reduction of the glomerular filtration rate by 8?10 ml/min was obtained only in the DD genotype (p=0.016), and only the DD genotype achieved a significant reduction of the filtration fraction by 0.019?0,022 (p=0.008). The most pronounced increase of the effective renal plasma flow was found only in the ID genotype (536 ?75 vs 591?63 ml/min; p=0.01). The reduction of the renal vascular resistance was independent of ACE gene polymorphism. Conclusion. Our study shows that individual renal vascular response to losartan treatment in diabetic patients with persistent albuminuria, could be influenced by genetic polymorphisms.

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