Renal nerves and cation excretion after acute reduction in functioning renal mass in the rat

1984 ◽  
Vol 246 (3) ◽  
pp. F260-F265 ◽  
Author(s):  
J. Ribstein ◽  
M. H. Humphreys
Keyword(s):  
Glomerular Filtration Rate ◽  
Mean Arterial Pressure ◽  
Renal Mass ◽  
Filtration Rate ◽  
Renal Nerves ◽  
Potassium Excretion ◽  
Contralateral Kidney ◽  
Efferent Limb ◽  
Ureteral Occlusion

We evaluated the role of the renal nerves in the increased cation excretion by the contralateral kidney after acute unilateral nephrectomy (AUN) or unilateral ureteral occlusion (UUO) in anesthetized rats. Both AUN and UUO caused large increases in sodium (UNaV) and potassium excretion (UKV) by the control kidney without change in glomerular filtration rate or mean arterial pressure. Prior denervation of either the ipsilateral (experimental) kidney or the control kidney completely prevented the increase in UNaV and UKV after UUO. Prior denervation of either kidney also prevented the increase in UNaV after AUN. However, a significant kaliuresis persisted after AUN despite unilateral denervation although reduced in magnitude when compared with the increase in UKV after AUN with both kidneys innervated. These results indicate that the renal nerves play a major role in the excretory response of the control kidney after acute reduction in functioning renal mass. This role of the renal nerves may be through the activation of a renorenal reflex. The reflex is activated by afferents from the ipsilateral kidney; the efferent limb is composed of the renal nerves to the control kidney. This reflex can entirely account for the compensatory increase in cation excretion after UUO. However, a separate mechanism, not dependent on the renal nerves, contributes to UKV after AUN.

Reversible Renal Nerve Denervation in the Cat: Effects on Haemodynamic and Excretory Functions of the Ipsilateral and Contralateral Kidneys

1982 ◽  
Vol 63 (s8) ◽  
pp. 215s-217s ◽  
Author(s):  
R. Golin ◽  
A. Stella ◽  
A. Zanchetti
Keyword(s):  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Renal Nerves ◽  
Renal Nerve ◽  
Contralateral Kidney ◽  
Cooling Period ◽  
Renal Changes ◽  
Water And Sodium Excretion

1. In anaesthetized cats, reversible nenal nerve denervation (cooling of the renal nerves on one side at 4°C for 16 min) was performed and its effects on haemodynamic and excretory functions of the ipsilateral and the contralateral kidneys were studied. 2. Renal nerve cooling did not cause any change in arterial pressure. Slight increase in blood flow, no change in glomerular filtration rate and a large increase in water and sodium excretion occurred in the ipsilateral kidney; simultaneously, no change in blood flow, a slight and transient decrease in glomerular filtration rate, and a significant decrease in diuresis and natriuresis were observed in the contralateral kidney. 3. Ipsilateral and contralateral renal changes were equally evident in the early (minutes 0 to 8) and late phases (minutes 8 to 16) of the cooling period. 4. When renal nerve cooling was repeated after surgical denervation of the contralateral kidney all contralateral effects were abolished.

Effects of growth hormone and IGF-I on renal function in rats with normal and reduced renal mass

1990 ◽  
Vol 259 (5) ◽  
pp. F747-F751 ◽  
Author(s):  
S. B. Miller ◽  
V. A. Hansen ◽  
M. R. Hammerman
Keyword(s):  
Growth Hormone ◽  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Renal Mass ◽  
Filtration Rate ◽  
Inulin Clearance ◽  
Mass Reduction ◽  
Contralateral Kidney ◽  
Igf I

To characterize actions of growth hormone (GH) and insulin-like growth factor ( (IGF-I) on renal function in rats with normal and reduced renal mass, we administered recombinant bovine growth hormone (bGH) or human IGF-I (hIGF-I) to normal rats or to rats that had undergone unilateral nephrectomy and two-thirds infarction of the contralateral kidney, and measured inulin and p-aminohippurate clearances over 10-17 days. Administration of either bGH (100-200 micrograms/day) or hIGF-I (200 micrograms/day) to rats with normal renal mass increased inulin and p-aminohippurate clearances compared with those measured in animals that received vehicle. Filtration fractions were not affected by either bGH or hIGF-I. Inulin clearance was decreased to approximately 17% of normal 1 day after reduction of renal mass in rats. Over the next 3 days insulin clearance increased significantly in rats with reduced renal mass that were administered vehicle. No further enhancement occurred during the next 7 days. Neither bGH nor hIGF-I affected inulin clearance in rats with reduced renal mass. We conclude that both GH and IGF-I enhance glomerular filtration rate when administered to rats with normal renal mass, but not when administered in the same quantities to rats in which renal functional mass is reduced. Glomerular filtration rate increases within 4 days of renal mass reduction independent of exogenous GH or IGF-I.

Role of prostaglandins and renal nerves in the renal actions of adrenomedullin

1997 ◽  
Vol 272 (2) ◽  
pp. F260-F266 ◽  
Author(s):  
M. Jougasaki ◽  
L. L. Aarhus ◽  
D. M. Heublein ◽  
S. M. Sandberg ◽  
J. C. Burnett
Keyword(s):  
Glomerular Filtration Rate ◽  
Renal Cell ◽  
Filtration Rate ◽  
Renal Denervation ◽  
Renal Nerves ◽  
Sodium Reabsorption ◽  
Intravenous Bolus ◽  
Hemodynamic Effects ◽  
Terminal Nephron

Adrenomedullin (ADM), originally discovered in human pheochromocytoma, is also of renal cell origin and has natriuretic and diuretic actions. The present study was designed to investigate the role of prostaglandins and renal nerves in the renal hemodynamic and natriuretic actions ofADM. ADM was administered intrarenally (1, 5 and 25 ng x kg(-1) x min(-1)) with and without prostaglandin inhibition (meclofenamate, 5 mg/kg intravenous bolus) in anesthetized normal mongrel dogs (n = 5, each). To elucidate the role of renal nerves, ADM was administered intrarenally to the denervated kidney in five dogs. ADM mediated a natriuretic action via increases in glomerular filtration rate and decreases in distal tubular sodium reabsorption, which was attenuated by renal denervation and completely abolished by prostaglandin inhibition. The renal vasodilatation induced by ADM was attenuated by meclofenamate, as well as by renal denervation, although not significantly. Additionally, renal nerves mediated hemodynamic effects of hypertension that were produced by intrarenal infusion of ADM. This study establishes an important mechanistic role for renal prostaglandins as a mediator of ADM-mediated natriuresis at the level of the glomerulus and terminal nephron.

Endogenous opioids and electrolyte excretion after contralateral renal exclusion

1983 ◽  
Vol 244 (4) ◽  
pp. F392-F398 ◽  
Author(s):  
J. Ribstein ◽  
M. H. Humphreys
Keyword(s):  
Renal Mass ◽  
Opiate Receptors ◽  
Opiate Receptor ◽  
Endogenous Opioids ◽  
Subcutaneous Implantation ◽  
Electrolyte Excretion ◽  
Contralateral Kidney ◽  
Reflex Pathways ◽  
Ureteral Occlusion

Acute reductions in functioning renal mass result in increases in both sodium (U Na V) and potassium (U K V) excretion by the contralateral kidney (CK). We studied the role of endogenous opioids in this response. In control experiments acute unilateral nephrectomy (AUN) increased U Na V from 1,788 +/- 1,125 (SD) to 3,939 +/- 1,819 and U K V from 1,385 +/- 561 to 2,254 +/- 832 neq/min by the CK (P less than 0.005 for both); similar results occurred in rats undergoing acute unilateral ureteral occlusion (UUO). These increases occurred without overall change in GFR or mean arterial pressure. In rats receiving a continuous infusion of the opiate-receptor antagonist naloxone (0.3 mg . kg-1 . h-1) neither AUN nor UUO produced significant alterations in U Na V or U K V by the CK; naloxone infusion by itself did not alter GFR or basal rates of cation excretion. A separate group of rats was made tolerant to morphine by subcutaneous implantation of pellets containing 75 mg morphine base. In these rats, AUN also failed to produce any increase in U Na V or U K V by the CK. The results suggest that acute reductions in functioning renal mass produced by either AUN or UUO stimulate cation excretion by the remaining kidney through reflex pathways that involve opiate receptors.

Role of endothelium-derived nitric oxide in hemodynamic adaptations after graded renal mass reduction

1993 ◽  
Vol 264 (6) ◽  
pp. R1254-R1259 ◽  
Author(s):  
K. A. Griffin ◽  
A. K. Bidani ◽  
J. Ouyang ◽  
V. Ellis ◽  
M. Churchill ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Renal Mass ◽  
Filtration Rate ◽  
Plasma Renin ◽  
Mass Reduction ◽  
Synthesis Inhibitor ◽  
Contralateral Kidney ◽  
Before And After ◽  
Renal Vascular

The mediator(s) of the adaptive increases in renal blood flow (RBF) and glomerular filtration rate (GFR) after renal mass reduction have not been identified. The present studies were designed to investigate the role of endothelium-derived nitric oxide (EDNO) in the hemodynamic adaptations after graded renal mass reduction. The experiments were performed in rats that had undergone a sham reduction in renal mass, uninephrectomy (UNX), or 5/6 NX (UNX plus excision of both poles of the contralateral kidney) 3-4 wk before. Measurements of RBF, GFR, renal vascular resistance (RVR), mean arterial pressure (MAP), and plasma renin concentration (PRC) were obtained before and after administration of the EDNO synthesis inhibitor NG-monomethyl-L-arginine (L-NMMA). L-NMMA (50 mg/kg bolus plus 500 micrograms.kg-1.min-1 infusion) led to significant (P < 0.01) and comparable increases in MAP (mmHg) (P < 0.01) in sham rats (117 +/- 6 to 154 +/- 6), UNX rats (112 +/- 5 to 139 +/- 7), and 5/6 NX rats (116 +/- 5 to 149 +/- 7). RVR increased significantly in all three groups (P < 0.01). The resultant decrease in RBF (ml.min-1.kg-1) was similar in sham rats (34.9 +/- 2.6 to 23.8 +/- 1.6), UNX rats (43.9 +/- 3.6 to 27.3 +/- 2.8), and 5/6 NX rats (34.6 +/- 2 to 22.3 +/- 1.6) (P < 0.01 for all groups).(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Serum cystatin is not a marker of glomerular filtration rate in pregnancy

2009 ◽  
Vol 2 (3) ◽  
pp. 121-122 ◽  
Author(s):  
Kate Bramham ◽  
David Makanjuola ◽  
Wael Hussein ◽  
Debra Cafful ◽  
Hassan Shehata
Keyword(s):  
Glomerular Filtration Rate ◽  
Observational Study ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Prospective Observational Study ◽  
Second Trimester ◽  
Third Trimester ◽  
Serum Cystatin ◽  
In Pregnancy

The role of cystatin C (Cys-C) as a marker of glomerular filtration rate (GFR) in pregnancy is undetermined. Measurements of Cys-C and creatinine (Cr) were taken at 14–17+6, 18–23+6, 27–31+6 weeks' gestation, at delivery and 2–6 weeks postpartum in a prospective observational study of 27 women. There was no difference between Cys-C levels in early and late second trimester, but they were significantly higher in early third trimester ( P < 0.001) than second trimester, despite no concurrent increase in Cr. Cys-C was also significantly higher at delivery than at all other times in pregnancy ( P < 0.001) and fell to postpartum values higher than second trimester measurements ( P < 0.01), but lower than delivery ( P<0.001). In conclusion, changes in Cys-C may be influenced by pregnancy-related changes in glomerular filtration and therefore we would advise against their use as a marker of GFR in pregnancy.

Effects of blood pH changes on potassium excretion in the dog

1962 ◽  
Vol 202 (4) ◽  
pp. 768-772 ◽  
Author(s):  
Charles Toussaint ◽  
Pierre Vereerstraeten
Keyword(s):  
Glomerular Filtration Rate ◽  
Proximal Tubule ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Excretion Rate ◽  
Distal Tubule ◽  
Potassium Excretion ◽  
Ph Changes ◽  
Blood Ph ◽  
Ph Level

K+ excretion rate was measured at normal as well as at rising plasma K+ concentration in intact, in K-depleted, and in acetazolamide-treated dogs submitted to acute blood pH changes. The results indicate that, for any given value of glomerular filtration rate, K+ excretion rate is determined by at least three factors: 1) plasma K+ concentration, 2) blood pH level, and 3) presumably, the H+ gradient across the luminal border of the distal tubule. The data further suggest that most of the filtered K+ is reabsorbed by the proximal tubule, even in conditions of high filtered loads.

Genetic co-segregation of renal haemodynamics and blood pressure in the spontaneously hypertensive rat

1988 ◽  
Vol 74 (1) ◽  
pp. 63-69 ◽  
Author(s):  
S. B. Harrap ◽  
A. E. Doyle
Keyword(s):  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Glomerular Filtration ◽  
Renal Blood Flow ◽  
Filtration Rate ◽  
Spontaneously Hypertensive Rat ◽  
Plasma Renin ◽  
Spontaneously Hypertensive

1. To determine the relevance of renal circulatory abnormalities found in the immature spontaneously hypertensive rat (SHR) to the genetic hypertensive process, glomerular filtration rate and renal blood flow were measured in conscious F2 rats, derived from crossbreeding SHR and normotensive Wistar–Kyoto rats (WKY), at 4, 11 and 16 weeks of age by determining the renal clearances of 51Cr-ethylenediaminetetra-acetate and 125I-hippuran respectively. Plasma renin activity was measured at 11 and 16 weeks of age. 2. Mean arterial pressure, glomerular filtration rate and renal blood flow increased between 4 and 11 weeks of age. Between 11 and 16 weeks the mean glomerular filtration rate and renal blood flow did not alter, although the mean arterial pressure rose significantly. At 11 weeks of age, during the developmental phase of hypertension, a significant negative correlation between mean arterial pressure and both glomerular filtration rate and renal blood flow was noted. However, by 16 weeks when the manifestations of genetic hypertension were more fully expressed, no correlation between mean arterial pressure and renal blood flow or glomerular filtration rate was observed. Plasma renin activity was negatively correlated with both glomerular filtration rate and renal blood flow, but the relationship was stronger at 11 than at 16 weeks of age. 3. These results suggest that the reduction in renal blood flow and glomerular filtration rate, found in immature SHR, is genetically linked to the hypertension and may be of primary pathogenetic importance. It is proposed that the increased renal vascular resistance in these young animals stimulates the rise of systemic arterial pressure which returns renal blood flow and glomerular filtration rate to normal.

Increased tubuloglomerular feedback activity in Milan hypertensive rats

1986 ◽  
Vol 250 (6) ◽  
pp. F967-F974 ◽  
Author(s):  
U. Boberg ◽  
A. E. Persson
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Tubuloglomerular Feedback ◽  
Spontaneously Hypertensive ◽  
Arterial Blood ◽  
Single Nephron ◽  
Flow Pressure ◽  
Normotensive Strain

Studies of whole-kidney function and micropuncture measurements in superficial nephrons were performed to investigate the role of the tubuloglomerular feedback (TGF) in the excretion of salt and water in hydropenic and volume-expanded rats of the spontaneously hypertensive Milan strain (MHS). The rats were 3.5-5 and 5-7 wk old, and age-matched animals from the Milan normotensive strain (MNS) served as controls. There was no difference in mean arterial blood pressure (Pa) between the 3.5- to 5-wk-old prehypertensive MHS (MHSp) and MNS rats, but the glomerular filtration rate (GFR) was higher in MHSp than in MNS [1.35 vs. 0.80 ml X min-1 X g kidney wt (KW)-1, P less than 0.01]. The distal single-nephron glomerular filtration rate (SNGFR) was also higher in MHSp than in MNS (28.6 vs. 20.2 nl X min-1 X g KW-1, P less than 0.05). TGF was determined from both stop-flow pressure response and proximal and distal SNGFR. It was found that MHSp exhibited essentially no TGF response. During development of hypertension 5- to 7-wk-old MHS (MHSd) had a higher Pa than MNS (120 vs. 98 mmHg, P less than 0.01). Normally GFR and SNGFR increase with age, and such was the case with MNS (0.8 to 1.02 ml X min-1 X g KW-1 and 20.2 to 23.4 nl X min-1 X g KW-1), but in MHSd there was a decrease in both GFR and SNGFR with age (1.35 to 1.10 ml X min-1 X g KW-1 and 28.3 to 18.3 nl X min-1 X g KW-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Measuring renal function in old age

1999 ◽  
Vol 9 (3) ◽  
pp. 215-219 ◽  
Author(s):  
JM Coyle ◽  
BK Bhowmick ◽  
RJ Meara
Keyword(s):  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Old Age ◽  
Renal Mass ◽  
Filtration Rate ◽  
Elderly Subjects ◽  
Cross Sectional ◽  
Functional Changes ◽  
Progressive Loss ◽  
Stable Renal Function

The accurate measurement of renal function in elderly subjects is often required, due to structural and functional changes resulting from age and diseases affecting the kidney. Structurally, with age there is progressive loss of renal mass, particularly in the cortex, leading to a decreased number of glomeruli and an increase in the proportion of sclerotic glomeruli. A decline in the glomerular filtration rate (GFR) has been observed in both cross-sectional and longitudinal studies. However, it has also been noted that about one third of subjects have stable renal function, implying that this decline is not universal, and may reflect the effects of age-associated diseases.

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