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

Do vasopressin and oxytocin have synergistic renal effects in the conscious rat?

1995 ◽  
Vol 144 (3) ◽  
pp. 441-448 ◽  
Author(s):  
R J Windle ◽  
J M Judah ◽  
M L Forsling
Keyword(s):  
Filtration Rate ◽  
Fractional Excretion ◽  
Potassium Excretion ◽  
Conscious Rat ◽  
Renal Effects ◽  
Fractional Excretion Of Sodium ◽  
Dose Dependent ◽  
Higher Doses ◽  
Sodium And Potassium ◽  
Tubular Component

Abstract The renal effects of arginine vasopressin and oxytocin were studied in the conscious unrestrained rat infused with 0·077 m NaCl. Peptides were infused at rates of 24 and 160 pmol/min (vasopressin) or 30 and 200 pmol/min (oxytocin) either alone or as a combination of the two lower or two higher doses. The rates of infusion were selected to give ratios of oxytocin:vasopressin similar to those seen in the plasma of euhydrated and dehydrated rats. Vasopressin produced dose-dependent antidiuretic and natriuretic responses, the natriuresis commencing after 15–30 min infusion. Oxytocin produced dose-dependent diuretic and natriuretic responses, the natriuresis commencing within the first 15 min of infusion. Combined infusion of vasopressin and oxytocin produced dose-dependent antidiuretic responses which were comparable to those seen with vasopressin alone. The natriuretic response from combined infusion at the higher rate appeared to have the greater magnitude for individual 15-min periods of the vasopressin response combined with the longer duration of the oxytocin response. Although the total natriuretic response was therefore greater, this difference failed to reach significance. Only the higher rates of infusion of vasopressin and oxytocin significantly increased the clearance of sodium, by 53 ± 23 and 62 ± 18% and glomerular filtration rate (GFR) by 23 ± 4 and 23 ± 4% respectively. The clearance of sodium during the combined hormone infusion was significantly greater (109 ± 21%), while the rise in GFR at 23 ± 5% was comparable to that seen when each hormone was given separately. Both fractional excretion of sodium and potassium excretion were also significantly elevated by this combined infusion, suggesting an additional tubular component to the response. Although no synergistic effect of neurohypophysial hormones on the antidiuresis was found in the conscious rat, they may act together to promote sodium excretion Journal of Endocrinology (1995) 144, 441–448

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.

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.

Localization of alpha 2-adrenoceptor-mediated increase in renal Na+, K+, and water excretion

1987 ◽  
Vol 252 (6) ◽  
pp. F1016-F1021 ◽  
Author(s):  
B. Stanton ◽  
E. Puglisi ◽  
M. Gellai
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Water Transport ◽  
Filtration Rate ◽  
Distal Tubule ◽  
Fractional Excretion ◽  
Urine Osmolality ◽  
Water Excretion ◽  
Arterial Blood ◽  
Adrenoceptor Agonist

Free-flow micropuncture and clearance studies were conducted in male Sprague-Dawley rats to investigate the effects of alpha 2-adrenoceptor stimulation on Na+, K+, and water transport along the nephron. Intravenous infusion of the selective alpha 2-adrenoceptor agonist B-HT 933 at 1 mg X kg-1 X h-1 increased urinary flow rate from 16.2 +/- 3.6 to 84.8 +/- 11.9 microliter/min, fractional excretion of Na+ from 1.36 +/- 0.31 to 3.57 +/- 0.52%, and fractional excretion of K+ from 26.9 +/- 3.0 to 42.3 +/- 2.2%, The diuresis, saluresis, and kaliuresis were not the result of increases in glomerular filtration rate or mean arterial blood pressure. Urine osmolality decreased from 1,126 +/- 177 to 325 +/- 33 mosmol/kg water and in 8 of the 11 animals studied B-HT 933 decreased urine osmolality to hyposmotic levels, suggesting a possible interaction between the alpha 2-adrenoceptor agonist and vasopressin. The alpha 2-adrenoceptor antagonist yohimbine (0.25/mg bolus, iv) inhibited the diuresis, saliuresis, and kaliuresis. In micropuncture studies, B-HT 933 was without effect on single-nephron glomerular filtration rate or on Na+, K+, and water transport along the superficial proximal tubule, loop of Henle, or distal tubule. Thus stimulation of alpha 2-adrenoceptors increases Na+, K+, and water excretion by inhibiting tubule reabsorption of these substances at nephron sites beyond the superficial distal tubule, most likely by the collecting tubule.

Effect of inhibition of MAO and COMT on intrarenal dopamine and serotonin and on renal function

2001 ◽  
Vol 280 (1) ◽  
pp. R248-R254 ◽  
Author(s):  
Yongqing Wang ◽  
Theresa J. Berndt ◽  
Jennifer M. Gross ◽  
Michael A. Peterson ◽  
Mathew J. So ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Monoamine Oxidase ◽  
Filtration Rate ◽  
Interstitial Fluid ◽  
Fractional Excretion ◽  
Urine Flow ◽  
Arterial Blood ◽  
Fractional Excretion Of Sodium

The purpose of the present investigation was to study the effects of inhibition of monoamine oxidase (MAO) and/or catechol- O-methyltransferase (COMT), enzymes involved in the degradation of dopamine (DA) and serotonin (5-HT), on intrarenal DA and 5-HT, as reflected in the renal interstitial fluid (RIF) microdialysate and urine, and on renal function. Inhibition of MAO selectively increased RIF 5-HT from 3.16 ± 0.38 to 8.03 ± 1.83 pg/min ( n = 7, P < 0.05), concomitant with decreases in mean arterial blood pressure and glomerular filtration rate (2.09 ± 0.18 to 1.57 ± 0.22 ml/min, n = 7, P < 0.05). Inhibition of COMT significantly increased RIF DA (3.47 ± 0.70 to 8.68 ± 1.96 pg/min, n = 9, P < 0.05), urinary DA (2.00 ± 0.16 to 2.76 ± 0.26 ng/min, n = 9, P < 0.05), and absolute excretion of sodium (6.42 ± 2.00 to 9.82 ± 1.62 μmol/min, n = 10, P < 0.05). Combined inhibition of MAO and COMT significantly increased RIF DA, urinary DA, and urinary 5-HT, which was accompanied with increases in urine flow rate, and absolute (3.03 ± 0.59 to 8.40 ± 1.61 μmol/min, n = 9, P < 0.01) and fractional excretion of sodium. We conclude that inhibition of MAO selectively increases RIF 5-HT. COMT appears to be more important than MAO in the metabolism of intrarenal DA. Physiological increases in intrarenal DA/5-HT induced by inhibition of their degrading enzymes are accompanied with significant alterations of renal function.

Angiotensin-(1–7) in the ovine fetus

2001 ◽  
Vol 280 (2) ◽  
pp. R404-R409 ◽  
Author(s):  
Karen M. Moritz ◽  
Duncan J. Campbell ◽  
E. Marelyn Wintour
Keyword(s):  
Blood Pressure ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Flow Rate ◽  
Filtration Rate ◽  
Plasma Concentrations ◽  
Urine Flow ◽  
Urine Flow Rate ◽  
Ang Ii ◽  
Arterial Blood

In the adult animal, ANG-(1–7) may counterbalance some effects of ANG II. Its effects in the fetus are unknown. Basal ANG-(1–7), ANG I, ANG II, and renin concentrations were measured in plasma from ovine fetuses and their mothers ( n = 10) at 111 days of gestation. In the fetus, concentrations of ANG I, ANG-(1–7), and ANG II were 86 ± 21, 13 ± 2, and 14 ± 2 fmol/ml, respectively. In the ewe, concentrations of ANG I were significantly lower (20 ± 4 fmol/ml, P < 0.05) as were concentrations of ANG-(1–7) (2.9 ± 0.6 fmol/ml), whereas ANG II concentrations were not different (10 ± 1 fmol/ml). Plasma renin concentrations were higher in the fetus (4.8 ± 1.1 pmol ANG I · ml−1 · h−1) than in the ewe (0.9 ± 0.2 pmol · ml−1 · h−1, P < 0.05). Infusion of ANG-(1–7) (∼9 μg/h) for a 3-day period caused a significant increase in plasma concentrations of ANG-(1–7) reaching a maximum of 448 ± 146 fmol/ml on day 3 of infusion. Plasma levels of ANG I and II as well as renin were unchanged by the infusion. Urine flow rate, glomerular filtration rate, and fetal arterial blood pressure did not change and were not different than values in fetuses receiving a saline infusion for 3 days ( n = 5). However, the osmolality of amniotic and allantoic fluid was significantly higher in fetuses that received ANG-(1–7). Also, compared with the saline-infused animals, mRNA expression levels of renin, the AT1 receptor, and AT2 receptor were elevated in kidneys of fetuses that received infusions of ANG-(1–7). Infusion of an ANG-(1–7) antagonist {[d-Ala7]-ANG-(1–7), 20 μg/h} for 3 days had no effect on fetal blood pressure or renal function. In conclusion, although infusion of ANG-(1–7) did not affect fetal urine flow rate, glomerular filtration rate, or blood pressure, changes in fetal fluids and gene expression indicate that ANG-(1–7) may play a role in the fetal kidney.

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.

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.

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