A comparison of the development of renal hypertension in male and female rats

1998 ◽  
Vol 95 (4) ◽  
pp. 445-451 ◽  
Author(s):  
Rachel OKUNIEWSKI ◽  
Elizabeth A. DAVIS ◽  
Bevyn JARROTT ◽  
Robert E. WIDDOP

1.The objective of this study was to determine the influence of gender on the development of renal hypertension in Sprague–Dawley rats using the Goldblatt two-kidney, one-clip (2K1C) model. In addition, this study examined the effect of ovariectomy upon the development of hypertension in female rats. 2.At 10 weeks of age, male, intact female and ovariectomized female rats underwent clipping of the right renal artery or sham operation. Tail-cuff plethysmography was used to monitor the systolic blood pressure of all animals for 7 weeks post-clipping or sham operation. Rats were sub-grouped according to whether or not they developed hypertension (systolic blood pressure ⩾ 150 ;mmHg). 3.Within 2 to 3 weeks of clipping, hypertension was induced in only 53% (n = 120) of the intact female 2K1C rats, but in 83% (n = 18) of the male and 78% (n = 18) of the ovariectomized female rats. 4.Seven weeks after right renal artery clipping, plasma renin activity was determined in a subset of each group and was found to be 5–6 fold higher in male (17.29±4.04 ;ng angiotensin I·h-1·ml-1) and ovariectomized female (9.71±1.25 ;ng angiotensin I·h-1·ml-1) hypertensive rats compared with their respective normotensive or sham-operated counterparts (3.39±0.58 ;ng angiotensin I·h-1·ml-1 and 1.60±0.41 ;ng angiotensin I·h-1·ml-1 respectively) (P< 0.05, analysis of variance). In contrast, the plasma renin activity measured in intact female hypertensive rats was not significantly different from that measured in the corresponding 2K1C normotensive or sham-operated groups. 5.These results indicate that the success rate of inducing renal hypertension in Sprague–Dawley rats is higher in males than in intact females. Furthermore, these results suggest that the induction of 2K1C hypertension may be influenced by ovarian hormones.

1991 ◽  
Vol 66 (3) ◽  
pp. 523-532 ◽  
Author(s):  
Susan M. Kaup ◽  
Alison R. Behling ◽  
J. L. Greger

The purpose of the present studies was to examine the effect of ingestion of sodium and potassium salts of various fixed anions on blood pressure, and to assess interactions among electrolytes. In the first study, Sprague-Dawley rats fed on purified diets supplemented with Na salts of chloride, sulphate, bisulphate, carbonate and bicarbonate for 7 weeks developed higher blood pressures than rats fed on the basal diet. In a second study, rats fed on Na or K salts of HSO4, HCO3 or Cl had higher blood pressures than rats fed on the basal diet. Blood pressure measurements were not correlated with plasma volume, plasma renin activity, or plasma atrial natriuretic peptide concentrations at 7 weeks. Plasma renin activity was depressed in rats fed on supplemental Na and even more in rats fed on supplemental K salts rather than the basal diet. Generally, rats fed on supplemental Na excreted Na in urine and absorbed Na in the gut more efficiently than rats fed on the basal diet or diets supplemented with K, but the anions fed also altered Na absorption and excretion. In a third study, rats fed on diets supplemented with any Cl salt, but especially KCI, absorbed K more efficiently than those fed on the basal diet. In studies 1 and 2, the efficiency of urinary excretion of K was greatest when HCO3 and CO3 salts were fed and least when HSO4 salts were fed. Despite large variations in the efficiency of absorption and excretion of Na and K, tissue levels of the electrolytes remained constant.


1975 ◽  
Vol 48 (1) ◽  
pp. 17-26 ◽  
Author(s):  
F. H. H. Leenen ◽  
J. W. Scheeren ◽  
D. Omylanowski ◽  
J. D. Elema ◽  
B. Van Der Wal ◽  
...  

1. The relationships between the renin-angiotensin-aldosterone system, sodium and potassium balance and systolic blood pressure were studied during development of moderate (160–180 mmHg; clip i.d. 0.25 mm) and severe (200–230 mmHg; clip i.d. 0.20 mm) renal hypertension in rats with an undisturbed contralateral kidney. 2. In severely hypertensive rats renin activity in the peripheral plasma increased from day 9, by which time the systolic blood pressure was elevated to 160–180 mmHg. The rate of total corticosteroid and aldosterone production in vitro increased from day 14 and plasma renin substrate concentration increased from day 24. In moderately hypertensive rats, none of these changes occurred. 3. During the first 10 days after the application of 0.25 and 0.20 mm clips, sodium and potassium retention/g gain in body weight were higher than in sham-operated controls. During the next 10 days, the positive balance stabilized in animals with a 0.25 mm clip whereas, in animals with a 0.20 mm clip, sodium and potassium balance returned to the level of the sham-operated controls through increased renal losses. Despite these changes the systolic pressure rose further in animals with a 0.20 mm clip. 4. The initial sodium retention could be a factor in the early rise of blood pressure and could account for the delay in the rise of peripheral plasma renin activity. The subsequent loss of the retained sodium and potassium during the development of severe hypertension could have facilitated the rise in peripheral plasma renin activity, but did not initiate this rise.


1984 ◽  
Vol 246 (4) ◽  
pp. H573-H578
Author(s):  
B. Waeber ◽  
J. Nussberger ◽  
H. R. Brunner

A total of 75 male Wistar rats with one-kidney, one-clip renal hypertension was maintained on either a regular (RNa) or a low-salt (LNa) diet for 3 wk after clipping. Blood pressure in the unanesthetized rats was equally elevated independent of sodium intake. Plasma renin activity was higher in LNa animals, and blood pressure was renin dependent only in this group, as evidenced by the blood pressure response to 10 mg/kg captopril iv. There was no significant difference in plasma catecholamines between RNa and LNa rats, although in the former the sympathetic nervous system is believed to play a major role in sustaining high blood pressure. The acute intravenous administration of 0.5 mg/kg prazosin did not induce a more pronounced blood pressure fall in the RNa rats. Prazosin enhanced plasma norepinephrine levels similarly in both groups, but epinephrine levels only rose in the LNa animals. Prazosin also markedly stimulated plasma renin activity rendering blood pressure renin dependent even in RNa rats. Thus, using alpha 1-adrenoceptor blockade, it has not been possible to demonstrate that the blood pressure elevation of salt-repleted one-kidney, one-clip renal hypertensive rats is due to an enhanced sympathetic nerve activity. Data obtained with sympatholytic agents must be interpreted with great caution if renin activity cannot be kept unchanged.


Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Saki Maruyama ◽  
Yukiko Segawa ◽  
Hiroko Hashimoto ◽  
Tomoko Osera ◽  
Nobutaka Kurihara

Objective: One of foods indispensable to Japanese cuisine “Washoku” is algae, including Saccharina japonica (SJ) and Undaria pinnatifida. The intake of SJ is reported to decrease blood pressure (BP) in spontaneously hypertensive rats in some studies, and in 2-kidney, 1-clip hypertensive (2K1C) rats in our studies. Since SJ soaked in vinegar is often used in Japanese cuisine, we observed the effects of dietary intake of SJ soaked in vinegar on BP in 2K1C rats. Methods: Male Sprague-Dawley rats (6 wks) were treated with sham operation (SHAM) or clipping the left renal artery (2K1C). After surgery, the rats started receiving a control diet (C), a diet with 5.0% (w/w) SJ (S), or a diet with 5.0% SJ soaked in 5.0% (v/v) vinegar (SV). Systolic BP (SBP) was measured by a tail-cuff method every week for 6 weeks. At the end of the protocol, mean arterial BP (MAP) was measured in each rat under anesthesia. Results and Discussion: Analysis of variance shows that SBP was significantly higher in 2K1C-C than SHAM-C through the experimental period (P<0.001), and that SBP was lower in 2K1C-S (P<0.05) and -SV (P<0.001) than in 2K1C-C (Fig). It also demonstrated that 2K1C-SV provided a significant reduction in SBP compared with 2K1C-S (p<0.001). At the end of the protocol, MAP in 2K1C-C was significantly higher than SHAM-C (154±4 vs 141±4 mmHg, P<0.05). Compared with 2K1C-C, a significant reduction in MAP was observed not in 2K1C-S (143±2 mmHg) but in 2K1C-SV (133±4 mmHg, p<0.05). Soaking in vinegar might bring alginate, which is one of possible components playing an important role in decreasing BP by SJ, to a low molecule and enhance the effect. Conclusion: SJ soaked in vinegar may decrease BP more than SJ in 2K1C rats.


1992 ◽  
Vol 83 (2) ◽  
pp. 165-170 ◽  
Author(s):  
Pi-Chin Yu ◽  
Jon-Son Kuo ◽  
Han-Chieh Lin ◽  
May C. M. Yang

1. Effects of endothelin-1 on systemic arterial blood pressure, heart rate and portal venous pressure were compared in normal Sprague-Dawley rats and rats with portal hypertension induced by CCl4 and partial portal vein ligation. 2. Endothelin-1 produced biphasic effects on systemic blood pressure and portal venous pressure in all three groups of rats. However, the magnitude of the changes in blood pressure was less in portal hypertensive rats. 3. The ability of endothelin-1 to increase the portal venous pressure was also significantly diminished in portal hypertensive rats. On the other hand, the initial decrease in portal pressure was augmented in rats with partial portal vein ligation, and disappeared at higher dosage in CCl4-treated rats. 4. In accordance with the pressure recording in vivo, the dose-response vasoconstrictive activity of endothelin-1 was significantly attenuated in the intrahepatic vasculature. 5. The plasma immunoreactive endothelin concentration was significantly higher (5.55 ± 0.81 fmol/ml) in Sprague-Dawley rats than in CCl4-treated rats (2.83 ± 0.56 fmol/ml) and rats with partial portal vein ligation (2.68 ± 0.53 fmol/ml). 6. It was concluded that a lower plasma level of endothelin and a reduced vascular responsiveness may contribute, at least in part, to the hyperdynamics of portal hypertension.


1982 ◽  
Vol 32 (4) ◽  
pp. 742-745 ◽  
Author(s):  
Yukio HASEGAWA ◽  
Takushi X. WATANABE ◽  
Koichiro KAWASHIMA ◽  
Hirofumi SOKABE ◽  
Ken SAITO

1992 ◽  
Vol 82 (4) ◽  
pp. 389-395 ◽  
Author(s):  
C. Stonier ◽  
J. Bennett ◽  
E. A. Messenger ◽  
G. M. Aber

1. The effect of oestradiol alone and in combination with indomethacin on blood pressure, erythrocyte cation concentration and Na+−K+ flux has been studied in adult female normotensive and spontaneously hypertensive rats. 2. Oestradiol alone resulted in a significant decrease in blood pressure in spontaneously hypertensive rats (from 165.3 ± 3.9 to 146.4 ± 2.7 mmHg, P < 0.001), whereas it induced a significant increase in normotensive rats (from 111.8 ± 1.8 to 124.1 ± 3.6 mmHg, P < 0.001). When indomethacin and oestradiol were administered simultaneously or when indomethacin was given alone, no change in blood pressure occurred in spontaneously hypertensive rats (158.6 ± 6.9 and 159.8 ± 6.2 mmHg, respectively). 3. The fall in blood pressure induced by oestradiol in spontaneously hypertensive rats was associated with significant reductions in erythrocyte K+ concentration (from 127.4 ± 1.2 to 116.9 ± 1.7 mmol/l of cells, P < 0.001), in erythrocyte Na+ concentration (from 14.3 ± 0.8 to 13.0 ± 0.6 mmol/l of cells, P < 0.02), in ouabain-sensitive erythrocyte Na+ flux (from 17.8 ± 0.3 to 16.0 ± 0.4 mmol h−1 (1 of cells)−1, P < 0.01) and in ouabain-sensitive erythrocyte K+ flux (from 11.4 ± 0.2 to 10.4 ± 0.2 mmol h−1 (1 of cells)−1, P < 0.01). No change in blood pressure, erythrocyte cation concentration or Na+−K+ flux occurred when oestradiol and indomethacin were given together or when indomethacin was administered alone. 4. The hypertensive influence of oestradiol in normotensive rats was unaccompanied by any changes in erythrocyte K+ concentration, erythrocyte Na+ concentration and total, ouabain-sensitive and ouabain-resistant Na+−K+ flux. 5. The divergent changes in blood pressure noted in the two strains occurred despite comparable changes in plasma renin activity after oestradiol, with significant increases in plasma renin activity in normotensive rats (from 16.4 ± 4.2 to 28.4 ± 6.6 ng of angiotensin I h−1 ml−1, P < 0.05) and in spontaneously hypertensive rats (from 28.3 ± 2.7 to 39.5 ± 5.7 ng of angiotensin I h−1 ml−1, P < 0.01). The plasma renin activity in spontaneously hypertensive rats receiving oestradiol or indomethacin and oestradiol were similar with values of 39.5 ± 5.7 and 40.6 ± 5.7 ng of angiotensin I h−1 ml−1, respectively, but were significantly higher than that seen in control animals (28.3 ± 2.7 ng of angiotensin I h−1 ml−1, P < 0.01). Similarly, indomethacin alone induced a significant increase in plasma renin activity in spontaneously hypertensive rats to 35.8 ± 7.6 ng of angiotensin I h−1 ml−1 (P < 0.05). 6. The contrasting effects of oestradiol on blood pressure in the two rat strains occurred without any change in packed cell volume. Likewise, the changes in blood pressure in spontaneously hypertensive rats with either oestradiol alone or in combination with indomethacin occurred without any change in packed cell volume, although indomethacin alone resulted in a significant reduction in packed cell volume (from 30.9 ± 1.6 to 26.8 ± 2.0, P < 0.01). 7. The results suggest that the hypotensive action of oestradiol in spontaneously hypertensive rats might be mediated through its influence on erythrocyte cation concentration and/or the modulation of Na+−K+ flux either directly or via the action of prostanoids.


Hypertension ◽  
2012 ◽  
Vol 60 (suppl_1) ◽  
Author(s):  
Mark M Knuepfer ◽  
Nathan E Billington ◽  
Laura A Willingham ◽  
Julie E Langasek ◽  
Willis K Samson ◽  
...  

Renal denervation decreases arterial pressure (AP) in hypertensive rats and humans. This procedure destroys both afferent and efferent nerves. Several investigators have proposed that renal afferent nerves contribute to the elevated AP. We developed a procedure to selectively remove renal afferent nerves with capsaicin (1-100 mM) both topically on the nerve and in the renal pelvis. We examined the effects of renal deafferentation on the development of genetic and renal hypertension. We studied spontaneously hypertensive rats (SHR), and a model of renal hypertension, two kidney-one clip (2K1C) in Sprague-Dawley rats. SHR were treated at 3-4 weeks of age with capsaicin. Mean arterial pressure was recorded by tail cuff through 16 weeks of age. On week 17, rats were cannulated, allowed 3 days to recover then had their AP measured directly for 3 days (3 hrs/day). Rats with renal deafferentation (n=11) had lower arterial pressure weeks 9-16 (average reduction AP=10.1±1.4 mmHg, ANOVA, p=0.0049) compared to control (saline treated, n=6) although the final direct recording was not significantly different on week 17 (control AP=184.1±3.4 mmHg vs deafferented AP=173.9±4.3 mmHg, p=0.07). Substance P levels from the kidneys were reduced in deafferented rats compared to control (6.9±1.0 vs 17.3±5.2 pg/g protein, p=0.0009). In contrast, renal NE levels were not altered (307±19 vs 313±20 pg/g protein, p=0.428). In the second study, the left kidney in weanling Sprague-Dawley rats was exposed to capsaicin or saline. Rats were allowed to mature (>250 g BW) then subjected to left renal artery clipping (0.2mm) or sham clip. AP was recorded by tail cuff during development of 2K1C for 6 weeks before direct cannulation to record AP on week 7. Renal deafferentation prevented the development of hypertension in 13 rats compared to 9 saline treated rats (average reduction AP=16.9±2.7 mmHg, ANOVA, p=0.0031). Saline treated rats had a higher AP 7 weeks after clipping (147.1±10.2 vs 130.5±4.2 mmHg direct recording, p=0.02). The left kidney contained 48% SP compared to the right kidney (p=0.04). These data suggest that increased afferent renal nerve activity contributes to the elevation in AP in hypertension and contributes to essential hypertension in humans. Supported by USPHS DA017371.


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