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Query: UNIPROT:Q9UID3 (
FFR
)
233
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
To investigate the vascular endothelial dysfunction in the insulin resistance syndrome, muscarinic and alpha2-adrenergic mediated relaxations were studied in the fructose-fed rat. Male Sprague-Dawley rats were fed either fructose-rich chow (
FFR
, n=14) or normal chow (CNT, n=13) for 8 weeks. Systolic blood pressure (SBP) was measured by the tail-cuff method. A 3 mm segment of mesenteric artery was cannulated and pressurized, pretreated with prazosin (10(-6) mol/l) and propranolol (3x10(-6) mol/l), then pre-contracted with serotonin (10(-6) mol/l). Endothelium-dependent relaxation was induced by addition of acetylcholine (ACh, 10(-9)-10(-4) mol/l) or a selective alpha2-agonist, B-HT 920 (10(-9)-10(-5) mol/l), with or without the nitric oxide (NO) synthase inhibitor, L-NAME (10(-4) mol/l). SBP was significantly elevated in
FFR
but not in CNT. Plasma triglyceride in FFT (241+/-115 mg/dl) was significantly (p<0.01) higher than in CNT (84+/-34 mg/dl). Insulin and insulin/glucose ratio were higher but not significantly. Plasma glucose was not different between the two groups. In the dose-response curves to ACh, maximum relaxation and ED50 were similar between
FFR
and CNT. Moreover, L-NAME shifted the dose-response curves similarly to the right in both groups. Dose-response curves to B-HT 920, however, showed less relaxation in
FFR
than in CNT (p<0.05). B-HT 920-induced relaxations were mostly abolished by L-NAME. It is concluded that endothelial alpha2-adrenergic relaxation, predominantly mediated by NO, is likely more sensitive to the development of insulin resistance than muscarinic receptor relaxation in this 8-weeks
FFR
model. This early impairment of endothelial alpha2-adrenergic relaxation may contribute to the development of
hypertension
and insulin resistance in the
FFR
.
...
PMID:Impaired endothelial alpha-2 adrenergic receptor-mediated vascular relaxation in the fructose-fed rat. 1204 35
Insulin resistance and impairment of the renal depressor system have been thought to be involved in the development of essential hypertension. However, the relationship between insulin resistance and this system is still unclear. To clarify this relationship, we investigated the role of the renal depressor system in a rat model of insulin-resistant
hypertension
. Sprague-Dawley rats were fed a standard diet (control) or a fructose-rich diet (
FFR
), and their blood pressures were measured every week. Urinary dopamine (uDA), urinary kallikrein (uKAL) activity and urinary nitric oxide (uNOx) levels were also measured each week, and the renal mRNA expression levels of endothelial nitric oxide synthase (eNOS), aromatic-L-amino-acid decarboxylase (AADC), and kallikrein (KAL) activity were compared at the end of the study. The blood pressure of
FFR
was elevated significantly from 2 weeks after the start of fructose loading. The uDA level was lower in
FFR
than in control rats throughout the study period (p<0.01), and the expression level of AADC mRNA was enhanced in
FFR
(p<0.05). There was a tendency of negative correlation between uDA level and systolic blood pressure (SBP) (r=-0.49, p=0.056). uNOx level was lower in
FFR
throughout the study period (p<0.05), and the eNOS mRNA expression level in the kidney was lower in
FFR
than in control rats (p<0.05). There was a negative correlation between uNOx level and SBP (r=-0.68, p <0.01). On the other hand, there was no significant difference in the kallikrein-kinin system between
FFR
and control rats. In conclusion, impairment in functions of the renal dopamine and NO systems occur in
FFR
, and this impairment may be caused by insulin resistance and may contribute to the development of
hypertension
.
...
PMID:The role of renal natriuretic and depressor systems in insulin-resistant hypertensive rats. 1530 87
Insulin resistance and compensatory hyperinsulinemia often coexist in hypertensive patients, which may play a role in the development of
hypertension
. Because medullary blood flow (MBF), which is strongly influenced by the nitric oxide (NO) system, is thought to be an important component of blood pressure and sodium balance, we focused particularly on MBF in fructose-induced hypertensive rats. Moreover, it has been reported that the increased reactive oxygen species (ROS) in the kidney may contribute to the development of
hypertension
. Our study was thus designed to test the hypotheses that MBF is diminished in fructose-hypertensive rats (
FFR
) and that administration of tempol, a membrane-permeable mimetic of superoxide dismutase (SOD), decreases mean arterial pressure (MAP) by increasing MBF. Male Sprague-Dawley rats (180 to 200 g) were divided into 6 groups: control untreated (C, n = 5), control tempol-treated (in drinking water) (CT, n = 4), control L-arginine-treated (in drinking water) (CA, n = 6), fructose-fed untreated (F, n = 7), fructose-fed tempol-treated (FT, n = 7), and fructose-fed L-arginine-treated rats (in drinking water) (FA, n = 6). MAP and 24-hour urine samples were measured weekly over a 4-week test period. Changes in MBF, cortical blood flow (CBF), and renal blood flow (RBF) were determined by implanted optical fiber-, laser- and pulse-Doppler flow measurement techniques 4 weeks after starting the diet. Fructose feeding resulted in hyperinsulinemia, significantly elevated MAP, decreased MBF without changes in RBF or CBF, and decreased sodium excretion in the F group compared to the C group. Administration of tempol significantly decreased MAP and plasma insulin in contrast to increased MBF and sodium excretion in the FT group compared to those in the F group. Results indicated that MBF played an important role in the development of
hypertension
in the F group. Impairment of renal medullary NO systems may induce sustained elevation of blood pressure and retention of sodium in fructose-fed rats. The decrease in MAP with an increase of MBF in the FT group is consistent with the hypothesis that tempol increases the level of NO available to influence mechanisms involved in the control of MBF.
...
PMID:Superoxide dismustase mimetic tempol decreases blood pressure by increasing renal medullary blood flow in hyperinsulinemic-hypertensive rats. 1537 86