BACKGROUND/AIMS: Cross-transplantation studies between animals with genetic hypertension and normotensive animals indicate a key role of the kidney in development of hypertension, and studies in young spontaneously hypertensive rats (SHR) have shown reduced glomerular filtration rate (GFR) and renal blood flow (RBF) for a short period at the age of 4-6 weeks during blood pressure increase. We tested the hypothesis that a decline in GFR during development of hypertension in SHR might be more pronounced in juxtamedullary cortex than other cortical zones. METHODS: By use of the aprotinin method, total and zonal cortical GFR was measured in anaesthetized Wistar-Kyoto (WKY) rats and SHR at the ages of 2, 4, 6, 8 and 10 weeks. RBF was measured by a transit time flowmeter. RESULTS: Body and kidney weights in SHR and WKY were not significantly different in any age group (p >0.05). Mean arterial blood pressure (MAP) was not different at the age of 2 weeks (79 +/- 6 mm Hg in SHR and 74 +/- 5 mm Hg in WKY, p > 0.05), but was significantly higher in 4-week-old SHR (104 +/- 1 mm Hg) compared to 4-week-old WKY (77 +/- 3 mm Hg) (p < 0.01). The difference in blood pressure increased with age from 4 to 10 weeks. RBF, total GFR, and outer, middle, and inner cortical GFR increased with age but were not different in SHR and WKY in any age group (p >0.05). Renal vascular resistance was increased from 4 weeks of age in SHR (21.5 +/- 1.8), significantly higher than WKY (14.4 +/- 0.9 mm Hg x ml(-1) x min.g) (p < 0.01) and stayed at higher values in older age groups (p < or = 0.01). CONCLUSION: RBF, total and zonal GFR are not significantly different in anaesthetized SHR compared to WKY at ages from 2 to 10 weeks and GFR in juxtamedullary cortex is not decreased in SHR during onset of hypertension. The results from the present study indicate that development of hypertension cannot be explained by a temporary decline in RBF or total or zonal GFR. Copyright 2002 S. Karger AG, Basel
BACKGROUND/AIMS: Cross-transplantation studies between animals with genetic hypertension and normotensive animals indicate a key role of the kidney in development of hypertension, and studies in young spontaneously hypertensiverats (SHR) have shown reduced glomerular filtration rate (GFR) and renal blood flow (RBF) for a short period at the age of 4-6 weeks during blood pressure increase. We tested the hypothesis that a decline in GFR during development of hypertension in SHR might be more pronounced in juxtamedullary cortex than other cortical zones. METHODS: By use of the aprotinin method, total and zonal cortical GFR was measured in anaesthetized Wistar-Kyoto (WKY) rats and SHR at the ages of 2, 4, 6, 8 and 10 weeks. RBF was measured by a transit time flowmeter. RESULTS: Body and kidney weights in SHR and WKY were not significantly different in any age group (p >0.05). Mean arterial blood pressure (MAP) was not different at the age of 2 weeks (79 +/- 6 mm Hg in SHR and 74 +/- 5 mm Hg in WKY, p > 0.05), but was significantly higher in 4-week-old SHR (104 +/- 1 mm Hg) compared to 4-week-old WKY (77 +/- 3 mm Hg) (p < 0.01). The difference in blood pressure increased with age from 4 to 10 weeks. RBF, total GFR, and outer, middle, and inner cortical GFR increased with age but were not different in SHR and WKY in any age group (p >0.05). Renal vascular resistance was increased from 4 weeks of age in SHR (21.5 +/- 1.8), significantly higher than WKY (14.4 +/- 0.9 mm Hg x ml(-1) x min.g) (p < 0.01) and stayed at higher values in older age groups (p < or = 0.01). CONCLUSION: RBF, total and zonal GFR are not significantly different in anaesthetized SHR compared to WKY at ages from 2 to 10 weeks and GFR in juxtamedullary cortex is not decreased in SHR during onset of hypertension. The results from the present study indicate that development of hypertension cannot be explained by a temporary decline in RBF or total or zonal GFR. Copyright 2002 S. Karger AG, Basel
Authors: Shetal H Padia; Nancy L Howell; Brandon A Kemp; Marie-Claude Fournie-Zaluski; Bernard P Roques; Robert M Carey Journal: Hypertension Date: 2009-12-07 Impact factor: 10.190
Authors: Shetal H Padia; Brandon A Kemp; Nancy L Howell; John J Gildea; Susanna R Keller; Robert M Carey Journal: Hypertension Date: 2008-12-15 Impact factor: 10.190
Authors: Brandon A Kemp; Nancy L Howell; Susanna R Keller; John J Gildea; Weijian Shao; Luis Gabriel Navar; Robert M Carey Journal: J Am Heart Assoc Date: 2019-05-07 Impact factor: 5.501