Compensatory renal hypertrophy in dogs: single nephron glomerular filtration rate

1977 ◽  
Vol 55 (1) ◽  
pp. 105-110 ◽  
Author(s):  
Serge Carrière ◽  
Michèle Gagnan-Brunette
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Left Kidney ◽  
Urine Volume ◽  
Free Water ◽  
Fractional Excretion ◽  
Fractional Excretion Of Sodium ◽  
Significant Difference ◽  
Single Nephron

Sodium ferrocyanide was used to measure the intrarenal distribution of single nephron glomerular filtration rate (SNGFR) in remaining kidneys of dogs, 10 d after contralateral nephrectomy. It was first demonstrated that the renal function of both kidneys in situ was comparable. Following right nephrectomy, the urine volume, p-aminohippuric acid clearance, creatine clearance, osmolar clearance, fractional excretion of potassium, and sodium excretion of the left kidney increased. Fractional excretion of sodium, free water clearance, and filtration fraction remained unchanged. Following that 10-d period, left kidney weight exceeded that of the previously removed contralateral kidney by 50%, indicating that most of the compensatory hypertrophy had already occurred. No significant difference in the length of the proximal tubule nor in the diameter of the glomeruli of superficial (SUP) and juxtamedullary (JM) nephrons of either kidney could be demonstrated. Most importantly, the ratio of radioactivity in the SUP/JM nephrons of the residual kidney was comparable with that previously observed in normal dog kidneys. Thus, the increase in total kidney GFR is explained through a proportional increase in the SNGFR of the SUP and JM nephrons.

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.

Effect of synthetic ANP on renal and loop of Henle functions in the young rat

1986 ◽  
Vol 251 (2) ◽  
pp. F220-F225 ◽  
Author(s):  
D. R. Roy
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Wistar Rats ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Urine Volume ◽  
Fold Increase ◽  
Young Female ◽  
Constant Infusion ◽  
Single Nephron

The present studies were undertaken to determine, by recollection micropuncture, the effect of a synthetic atrial natriuretic peptide (ANP) on the absolute and fractional deliveries of water and sodium to the juxtamedullary end-descending limb. Two groups of young female Munich-Wistar rats were studied: control (n = 8) received the vehicle only; and ANP (n = 12) received a prime followed by the constant infusion of a synthetic rat atrial peptide (28 amino acids). With the infusion of ANP, clearance of p-[14C]aminohippurate [( 14C]PAH) and glomerular filtration rate (GFR) fell significantly. Despite this fall in GFR and renal plasma flow, ANP produced a 2-fold increase in urine volume and a 10-fold increase in sodium excretion. Absolute and fractional sodium deliveries to the end-descending limb increased by approximately 30% in the ANP group, whereas mean juxtamedullary single-nephron glomerular filtration rate (SNGFR) remained stable. In three additional rats prepared for micropuncture of the superficial end-accessible proximal tubule, ANP reduced cortical SNGFR by approximately 15%. By contrast, GFR did not decline in response to ANP in larger rats, when treated identically. We conclude that in young rats ANP can produce a natriuresis in the absence of a rise in GFR; the fall in GFR observed following ANP is due presumably to the immaturity of the animals used in these studies; and ANP produces a rise in absolute and fractional water and sodium deliveries to the end-descending limb that cannot be attributed to a change in SNGFR.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Micropuncture study of avian kidney: effect of prolactin

1992 ◽  
Vol 262 (5) ◽  
pp. R933-R937 ◽  
Author(s):  
J. R. Roberts ◽  
W. H. Dantzler
Keyword(s):  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Fractional Excretion ◽  
Slight Reduction ◽  
Plasma Parameters ◽  
Single Nephron ◽  
Ovine Prolactin ◽  
Fractional Excretion Of Phosphate

Renal function was studied in anesthetized European starlings (Sturnis vulgaris) by micropuncture and clearance techniques. A previous study had shown some changes in the renal function of birds in molt. Endogenous prolactin levels have been shown to be elevated at this time. In the present study, renal function was studied during the infusion of an isotonic sodium chloride solution and then when ovine prolactin was added to the infusion. Ovine prolactin resulted in an elevation of plasma urate concentration but had no significant effects on other plasma parameters or on the concentration of the various ions in tubular fluid samples. Urine flow rate was significantly higher during prolactin infusion, although whole animal glomerular filtration rate, single nephron glomerular filtration rate, and the percentage fluid reabsorption in the proximal tubule (up to the point of micropuncture) were unaltered. The whole animal fractional excretions of sodium and chloride were significantly higher, those of magnesium and potassium were significantly lower, and the fractional excretion of phosphate tended to be lower during prolactin infusion. At the level of the proximal tubules of the reptilian-type nephrons, prolactin infusion caused a slight reduction in the net reabsorption of sodium and chloride. Therefore the main effects of prolactin on renal function are occurring in the distal nephron of the reptilian-type nephrons or in the mammalian-type nephrons. It appears that prolactin may affect renal function in avian species and that these actions may be modulated by a range of factors as has been demonstrated in mammals.

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.

Vitamin B12 Handling by the Kidney, a Major Site of B12 Traffic: Normal and Abnormal Physiology.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1855-1855 ◽  
Author(s):  
Hesham Hazin ◽  
Kotresha Neelakantappa ◽  
Lakshmi Ramasahayam ◽  
Ahmed Abdel-Maksoud ◽  
Josua Fogel ◽  
...  
Keyword(s):  
Glomerular Filtration Rate ◽  
Vitamin B12 ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Fractional Excretion ◽  
Normal Subjects ◽  
Tubular Reabsorption ◽  
Major Site ◽  
Control Subjects ◽  
Significant Difference

Abstract Background : The kidney is a major site of daily vitamin B12 (B12) processing. It filters transcobalamin (TC) II-bound B12 (holoTCII; the transport protein that delivers its B12 to all cells) and reabsorbs holoTCII in the proximal tubule via megalin, a multiligand receptor for TCII. The process, its quantitation, and the roles of TCI and TCII are still poorly characterized in normal subjects or in renal failure, in which serum B12 levels often rise. It is assumed that this rise in serum B12 reflects decreased renal clearance, but little is known about the details. The fractional excretion (FE) has not been measured but would be expected to approach zero for an essential vitamin, denoting a 100% tubular reabsorption. We characterized the tubular reabsorption and urinary excretion of B12 and holoTCII, as well as quantitating the distribution of serum B12 among its TC carriers (because B12 does not circulate unbound) in normal subjects and patients with acute kidney injury (AKI). Methods: Serum and 24-hour urine B12 (Roche assay) and holoTC II (Axis-Shield assay) were measured directly in 10 AKI patients and 10 control subjects. AKI was diagnosed by a recent increase in BUN/creatinine 3 times their baseline; glomerular filtration rate (GFR) was 12 ± 9 ml/min. Normal subjects were selected who had no renal co-morbidities and had a normal BUN/creatinine and glomerular filtration rate (GFR = 95 ± 36). Holo-nonTCII, which is identical to holoTCI in serum but whose nature is still undefined in urine, was calculated by subtracting holoTCII from (total) B12. FE, a measure of the filtered amount that is not reabsorbed, was calculated for B12, holoTCII, and holo-nonTCII. Group data were compared using ANOVA, with log transformation for skewed distributions. Correlation coefficients were calculated by Spearman rank test. Results: Serum total B12 (p<0.001), holo-TC II levels (p=0.005), and serum holoTCI levels (p<0.005) were significantly increased in AKI (see Table). Consonant with the importance of tubular reabsorption of B12, reabsorption fell and FE of B12 increased 4.4- fold in AKI (p<0.001), and FE of holoTCII increased 3.2-fold (p=0.007). Nevertheless, the 24-hour excretion of B12 and holo-TCII did not change significantly from normal in AKI, presumably because reduced GFR counterbalanced the decreased tubular reabsorption and increased FE. Serum, urine, and FE findings for holo-nonTCII, whose levels exceeded holoTCII in both serum and urine, resembled those for total B12 and holoTCII (Table). Moreover, relatively less B12 was found as holoTCII in urine in AKI than in control subjects (11.7% ± 7.2 vs. 20.2% ± 6.4; p=0.012) and more was found as holo-nonTCII; these ratios did not differ in AKI serum, however. B12 AKI Serum (pmol/l) 1611±1153* Urine (pmol/24hr) 115±88 Fractional Excretion (%) 0.70±0.35* Controls 369±100 75±32 0.15±0.08 * p <0.001 ** p≤0.005 ▴ p=0.007 TCII AKI 232±148** 13±16 0.50±0.39▴ Controls 100±76 14±8 0.15±0.10 NonTCII AKI 1378±1128** 102±81 1.13±1.33* Controls 269±100 60±26 0.19±0.14 Conclusion: The patients with AKI revealed an approximately fourfold increase in FE of B12, holoTCII, and holo-nonTCII (possibly TCI) compared with controls. This indicates a dramatic loss of tubular reabsorption, consistent with the tubular necrosis of AKI. Although there is no significant difference in the 24-hour urinary output of B12 and the TCs, our data show that urinary B12 excretion is neither increased nor decreased in AKI. Presumably, this reflects in part, a balance between reduced glomerular filtration and reduced tubular reabsorption. The diminished reabsorption of B12 and holoTCII probably arises from disruption of uptake by tubular megalin, which requires further documentation. One net result of the previous events is a rise in serum B12, holoTCII and non-holoTCII in AKI. The serum B12 elevation has been described in the past and is particularly striking in this study, as is the new observation of TC I (non-holoTCII). It is presumed to reflect the loss of normal glomerular filtration, as discussed, but the possibility of contributions from extrarenal sources and events must also be considered.

The effect of vasopressin and oxytocin on glomerular filtration rate in the conscious rat: contribution to the natriuretic response

1994 ◽  
Vol 141 (1) ◽  
pp. 59-67 ◽  
Author(s):  
M L Forsling ◽  
J M Judah ◽  
R J Windle
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Plasma Concentrations ◽  
Fractional Excretion ◽  
Conscious Rat ◽  
Arterial Blood ◽  
Fractional Excretion Of Sodium ◽  
Dose Dependent ◽  
Higher Doses

Abstract Urine flow, sodium excretion, mean arterial blood pressure and glomerular filtration rate (GFR) were detennined in the conscious unrestrained rat infused with hypotonic saline. The effects of vasopressin infused at 24 and 160 pmol/min and oxytocin infused at 30 and 200 pmol/min were determined. The lower doses of each hormone gave plasma concentrations within the physiological range whereas the higher doses produced plasma concentrations equivalent to those seen following dehydration. Vasopressin produced dose-dependent antidiuretic and natriuretic responses. Hormone infused at both rates increased the clearance of sodium, but only the higher dose caused a significant increase in GFR. Fractional excretion of sodium was significantly elevated by both doses. Oxytocin produced dose-dependent diuretic and natriuretic responses. Again both rates of infusion increased the clearance of sodium, but only the higher dose caused a significant increase in GFR. The lower dose caused a significant increase in the fractional excretion of sodium. It appears, therefore, that increases in GFR may have a role in the natriuretic response to both hormones. However, this response can also be seen when GFR remains unchanged. This fact, together with the observed increases in the fractional excretion of sodium, indicates that these hormones have additional tubular actions. Journal of Endocrinology (1994) 141, 59–67

Renal Handling of Lithium and the Effects of Mannitol and Arginine Vasopressin in man

1995 ◽  
Vol 89 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Faruq H. Noormohamed ◽  
Ariel F. Lant
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Flow Rate ◽  
Arginine Vasopressin ◽  
Filtration Rate ◽  
Free Water ◽  
Fractional Excretion ◽  
Renal Handling ◽  
Fractional Clearance ◽  
Induced Changes

1. A study has been undertaken in six healthy male subjects to clarify whether post-proximal segments of the nephron contribute to the renal handling of lithium under conditions of maximal forced osmotic load diuresis and arginine vasopressin-induced antidiuresis. Increments in the fractional clearance of free water, as a measure of effect at the proximal tubule, were positively correlated with incremental changes in flow rate, factored for glomerular filtration rate (mean r = 0.80 ± 0.12, P < 0.001), and fractional excretion of lithium (mean r = 0.84 ± 0.06, P < 0.001). Changes in flow rate and fractional excretion of lithium were also closely correlated with one another (mean r = 0.81 ± 0.06, P < 0.001), and the mean slope of these regression lines was not significantly different from unity (1.18; 95% confidence interval 0.76–1.59). These results show that, under conditions of maximal hydration, mannitol-induced changes in proximal tubular function were closely correlated with induced changes in the fractional excretion of lithium. 2. Infusion of arginine vasopressin alone (0.5 m-units/min) caused a marked reduction in both fractional clearance of free water (10.7% ± 1.2% to −1.2% ± 0.2%, P < 0.001) and flow rate factored for glomerular filtration rate (14.0 ± 1.5 to 0.8 ± 0.2%; P < 0.001) while the fractional excretion of lithium showed only a small non-significant decrease (25.3% ± 2.0% to 23.3% ± 2.2%). A similar dissociation was noted between fluid and lithium excretion when arginine vasopressin was superimposed on mannitol infusion with reductions in the fractional clearance of free water (12.7% ± 1.0% to −0.9% ± 0.7%, P < 0.001) and flow rate (18.6% ± 1.5% to 5.7% ± 1.0%; P < 0.001), while the fractional excretion of lithium showed a significant increase (28.4% ± 1.7% to 33.1% ± 2.4%; P < 0.05). The lack of correlation between fluid and lithium excretion, in the presence of arginine vasopressin with or without mannitol, indicates that the late distal tubule and collecting duct have little or no significant capacity to reabsorb lithium. 3. These findings, taken as a whole, strengthen the view that renal tubular handling of lithium is primarily a proximal event.

Effects of water load on renal glomerular and tubular function in desert quail

1975 ◽  
Vol 229 (1) ◽  
pp. 222-228 ◽  
Author(s):  
EJ Braun ◽  
WH Dantzler
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Flow Rate ◽  
Filtration Rate ◽  
Free Water ◽  
Urine Flow ◽  
Tubular Function ◽  
Free Water Clearance ◽  
Water Load ◽  
Single Nephron

Effects of an acute intravenous water load on glomerular and tubular function were studied in the anesthetized desert quail Lophortyx gambelii. Total-kidney glomerular filtration rate (GFR) and single-nephron glomerular filtration rates (SNGFR) of reptilian-type and mammalian-type nephrons increased by more than 50% compared with the GFR and SNGFRs measured during a control mannitol diuresis. Despite the increase in GFR, urine flow rate was only 56% of that in control mannitol diuresis, free-water clearance (CH2o) remained at 1-2% of GFR, and the animals excreted only about 79% of the water load. More than 99% of the filtered sodium and 93% of the filtered water were reabsorbed during the water load. Possible reasons for the increased GFR and the failure to produce a dilute urine or excrete the water load are discussed.

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