scholarly journals Effect of intrarenally infused parathyroid hormone-related protein on renal blood flow and glomerular filtration rate in the anaesthetized rat

1996 ◽  
Vol 118 (8) ◽  
pp. 1995-2000 ◽  
Author(s):  
Thierry Massfelder ◽  
Niranjan Parekh ◽  
Karlhans Endlich ◽  
Christian Saussine ◽  
Michael Steinhausen ◽  
...  
1988 ◽  
Vol 74 (1) ◽  
pp. 63-69 ◽  
Author(s):  
S. B. Harrap ◽  
A. E. Doyle

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.


2018 ◽  
Vol 46 (6) ◽  
pp. e560-e566 ◽  
Author(s):  
Jenny Skytte Larsson ◽  
Vitus Krumbholz ◽  
Anders Enskog ◽  
Gudrun Bragadottir ◽  
Bengt Redfors ◽  
...  

1992 ◽  
Vol 262 (1) ◽  
pp. R90-R98 ◽  
Author(s):  
R. F. Wideman ◽  
R. P. Glahn ◽  
W. G. Bottje ◽  
K. R. Holmes

Using a simplified avian kidney model, renal arterial perfusion pressure (RAPP) was reduced from 120 (control) to 70 mmHg (near the glomerular filtration rate autoregulatory limit) and then to 46 mmHg (below the glomerular filtration rate autoregulatory range) in kidneys with ambient or partially restricted renal portal flow. Renal blood flow (RBF) was measured with a thermal pulse decay (TPD) system, using TPD thermistor probes inserted at three locations to evaluate regional differences in RBF. The clearance (CPAH) and extraction of p-aminohippuric acid were used to calculate renal plasma flow (RPF). CPAH, RPF, and RBF values were consistently lower for kidneys with restricted portal flow than for kidneys with ambient portal flow. Reducing RAPP to 46 mmHg did not significantly reduce CPAH, RPF, or RBF in the ambient group but did significantly reduce CPAH and RPF (regressed on RAPP) in the restricted group. RBF was not significantly affected when RAPP was reduced in the restricted group, although significant regional differences in blood flow were recorded. Renal vascular resistance decreased significantly as RAPP was reduced to 46 mmHg in the ambient group, confirming the renal autoregulatory response. In separate validation studies, significant reductions in RBF were detected by the TPD system during acute obstructions of portal and/or arterial flow. Overall, the results support previous evidence that avian RBF remains constant over a wide range of RAPPs. Observations of nonuniform intrarenal distributions of portal blood flow suggest that the portal system maintains the constancy of RBF in regions with proportionately high portal-to-arterial flow ratios.


1999 ◽  
Vol 86 (6) ◽  
pp. 1936-1943 ◽  
Author(s):  
W. B. Farquhar ◽  
W. L. Kenney

Aging is associated with a number of physiological changes that may cause the kidney to rely to a greater extent on vasodilatory PGs for normal functioning. Acute exercise has been shown to cause renal vasoconstriction that may be partially buffered by vasodilatory PGs. To determine the relative importance of renal PGs during exercise in older adults, we compared the renal effects of the PG inhibitor ibuprofen (1.2 g/day for 3 days) vs. a placebo control in a cohort of eight younger (24 ± 2 yr) and eight older (64 ± 2 yr) women during treadmill exercise (∼57% maximal oxygen consumption) in the heat (36°C). This over-the-counter dose of ibuprofen reduced renal PG (i.e., PGE2) excretion by 47% ( P < 0.05). Acute exercise in the heat caused dramatic decreases in glomerular filtration rate, renal blood flow, and sodium excretion in both age groups. PG inhibition was associated with greater decreases in urine production and free water clearance ( P < 0.05). There were no drug-related declines in glomerular filtration rate or renal blood flow. We conclude that PG inhibition has only modest effects on renal function during exercise. Also, the lack of hemodynamic changes with PG inhibition indicates that healthy well-hydrated older women are not in a renal PG-dependent state.


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