Intestinal vitamin D-dependent calbindin-D9k and alkaline phosphatase in spontaneously hypertensive rats

1991 ◽  
Vol 260 (5) ◽  
pp. G691-G697 ◽  
Author(s):  
D. L. Cloney ◽  
R. W. Gray ◽  
M. E. Bruns ◽  
S. H. Burnett ◽  
M. L. Smith ◽  
...  
Keyword(s):  
Vitamin D ◽  
Alkaline Phosphatase ◽  
Spontaneously Hypertensive Rats ◽  
Marker Enzyme ◽  
Hypertensive Rats ◽  
Intestinal Alkaline Phosphatase ◽  
Spontaneously Hypertensive ◽  
Calbindin D9k ◽  
Body Weights ◽  
Wistar Kyoto

Intestinal Ca2+ malabsorption has been described in spontaneously hypertensive rats (SHRs), but the molecular basis for this defect is unknown. In this study, we measured intestinal alkaline phosphatase and vitamin D-dependent Ca(2+)-binding protein (calbindin-D9k), two proteins implicated in the active pathway of intestinal Ca2+ absorption. Both proteins were measured in the small intestines of SHRs and their normotensive controls, Wistar-Kyoto rats, before, during, and after development of hypertension (4, 9, 14, 18, and 28 wk of age). At all ages, alkaline phosphatase activity in duodenum (0-6 cm) was decreased by 30-57% (P less than 0.001) and by 47-75% in the 2nd intestinal segment (6-12 cm) (P less than 0.001-0.05). Calbindin-D9k was decreased similarly. The decreases of calbindin were statistically significant (P less than 0.001-0.05) in the duodena at 4, 14, 18, and 28 wk (9-30% decreases) and in the 2nd segment at 4, 14, and 18 wk (38-69% decreases; P less than 0.001-0.005). Decreased calbindin in SHRs was documented in animals from two suppliers. The deficiencies of calbindin-D9k and alkaline phosphatase could not be attributed to malnutrition or to a generalized brush-border defect as indicated by body weights and the intestinal marker enzyme sucrase. Although calbindin-D9k was decreased in young SHRs, the serum 1,25-dihydroxycholecalciferol [1,25(OH)2D3] was increased by 59 and 129% in 4- and 9-wk-old SHRs (P less than 0.001), respectively; by contrast, serum 1,25(OH)2D3 was unchanged or decreased in older SHRs.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium and vitamin D metabolism in spontaneously hypertensive rats

1987 ◽  
Vol 253 (4) ◽  
pp. F712-F718
Author(s):  
C. H. Hsu ◽  
C. S. Yang ◽  
S. R. Patel ◽  
M. G. Stevens
Keyword(s):  
Vitamin D ◽  
Spontaneously Hypertensive Rats ◽  
Serum Levels ◽  
Dietary Vitamin ◽  
Vitamin D Metabolites ◽  
Hypertensive Rats ◽  
Deficient Diet ◽  
Vitamin D Metabolism ◽  
Spontaneously Hypertensive ◽  
Wistar Kyoto

We have studied the effect of dietary vitamin D restriction on serum levels of vitamin D metabolites in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). Both WKY and SHR were fed a vitamin D-deficient or a vitamin D-supplemented diet beginning at 4 wk of age. In vitamin D-supplemented animals, the serum 1,25-dihydroxycholecalciferol [1,25(OH)2D3] concentration of WKY (55.4+/- 6.6 pg/ml, n = 5) was similar to the level of SHR (46.3+/- 5.9 pg/ml, n = 5). Plasma calcium concentration was not different between WKY and SHR. In animals fed a vitamin D-deficient diet, the serum concentration of 1,25-(OH)2D3 of SHR (23.0+/- 1.3 pg/ml, n = 5) was significantly lower than that of WKY (67.6+/- 4.6 pg/ml, n = 5, P less than 0.01). Plasma 25-hydroxycholecalciferol level was markedly decreased in both WKY (3.6+/- 0.5 ng/ml, n = 7) and SHR (2.8+/- 0.4 ng/ml). The SHR, but not the WKY, developed hypocalcemia (WKY, 9.68 mg/dl; SHR, 6.70 mg/dl). Despite hypocalcemia, fasting urinary Ca2+ excretion of SHR exceeded that of WKY. We conclude that the lower 1,25(OH)2D3 level in SHR fed a vitamin D-deficient diet may be due to a defect in the synthesis of 1,25(OH)2D3. The low level of 1,25(OH)2D3 is associated with renal wasting of calcium and hypocalcemia in SHR.

Excess oxygen delivery during muscle contractions in spontaneously hypertensive rats

1995 ◽  
Vol 78 (1) ◽  
pp. 101-111 ◽  
Author(s):  
J. M. Lash ◽  
H. G. Bohlen
Keyword(s):  
Blood Flow ◽  
Oxygen Saturation ◽  
Oxygen Delivery ◽  
Spontaneously Hypertensive Rats ◽  
Muscle Contractions ◽  
Hypertensive Rats ◽  
Hemoglobin Oxygen Saturation ◽  
Spontaneously Hypertensive ◽  
Tissue Po2 ◽  
Wistar Kyoto

These experiments determined whether a deficit in oxygen supply relative to demand could account for the sustained decrease in tissue PO2 observed during contractions of the spinotrapezius muscle in spontaneously hypertensive rats (SHR). Relative changes in blood flow were determined from measurements of vessel diameter and red blood cell velocity. Venular hemoglobin oxygen saturation measurements were performed by using in vivo spectrophotometric techniques. The relative dilation [times control (xCT)] of arteriolar vessels during contractions was as large or greater in SHR than in normotensive rats (Wistar-Kyoto), as were the increases in blood flow (2 Hz, 3.50 +/- 0.69 vs. 3.00 +/- 1.05 xCT; 4 Hz, 10.20 +/- 3.06 vs. 9.00 +/- 1.48 xCT; 8 Hz, 16.40 +/- 3.95 vs. 10.70 +/- 2.48 xCT). Venular hemoglobin oxygen saturation was lower in the resting muscle of SHR than of Wistar-Kyoto rats (31.0 +/= 3.0 vs. 43.0 +/- 1.9%) but was higher in SHR after 4- and 8-Hz contractions (4 Hz, 52.0 +/- 4.8 vs. 43.0 +/- 3.6%; 8 Hz, 51.0 +/- 4.6 vs. 41.0 +/- 3.6%). Therefore, an excess in oxygen delivery occurs relative to oxygen use during muscle contractions in SHR. The previous and current results can be reconciled by considering the possibility that oxygen exchange is limited in SHR by a decrease in anatomic or perfused capillary density, arteriovenular shunting of blood, or decreased transit time of red blood cells through exchange vessels.

scholarly journals Aging Additively Influences Insulin- and Insulin-Like Growth Factor-1-Mediated Endothelial Dysfunction and Antioxidant Deficiency in Spontaneously Hypertensive Rats

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 676
Author(s):  
Kunanya Masodsai ◽  
Yi-Yuan Lin ◽  
Sih-Yin Lin ◽  
Chia-Ting Su ◽  
Shin-Da Lee ◽  
...  
Keyword(s):  
Growth Factor ◽  
Endothelial Dysfunction ◽  
Spontaneously Hypertensive Rats ◽  
No Production ◽  
Organ Bath ◽  
Insulin Like Growth Factor ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Nos Inhibitors ◽  
Wistar Kyoto

This study aimed to investigate the aging-related endothelial dysfunction mediated by insulin and insulin-like growth factor-1 (IGF-1) and antioxidant deficiency in hypertension. Male spontaneously hypertensive rats (SHRs) and age-matched normotensive Wistar–Kyoto rats (WKYs) were randomly divided into 24-week-old (younger) and 48-week-old (older) groups, respectively. The endothelial function was evaluated by the insulin- and IGF-1-mediated vasorelaxation of aortic rings via the organ bath system. Serum levels of nitric oxide (NO), malondialdehyde (MDA), catalase, and total antioxidant capacity (TAC) were examined. The insulin- and IGF-1-mediated vasorelaxation was significantly impaired in both 24- and 48-week-old SHRs compared with age-matched WKYs and was significantly worse in the 48-week-old SHR than the 24-week-old SHR. After pretreatments of phosphoinositide 3-kinase (PI3K) or NO synthase (NOS) inhibitors, the insulin- and IGF-1-mediated vasorelaxation became similar among four groups. The serum level of MDA was significantly increased, while the NO, catalase, and TAC were significantly reduced in the 48-week-old SHR compared with the 24-week-old SHR. This study demonstrated that the process of aging additively affected insulin- and IGF-1-mediated endothelial dysfunction in SHRs, which could be partly attributed to the reduced NO production and antioxidant deficiency.

Effects of dietary Ca2+ on erythrocyte Na+-transport systems in spontaneously hypertensive rats

1991 ◽  
Vol 81 (1) ◽  
pp. 107-112 ◽  
Author(s):  
K. Fujito ◽  
M. Yokomatsu ◽  
N. Ishiguro ◽  
H. Numahata ◽  
Y. Tomino ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Transport Systems ◽  
Hypertensive Rats ◽  
Na Transport ◽  
Spontaneously Hypertensive ◽  
Na Pump ◽  
Wistar Kyoto ◽  
Increased Activity ◽  
Regulation Of Blood Pressure

1. The purpose of this study was to determine the effect of dietary Ca2+ intake on blood pressure and erythrocyte Na+ transport in spontaneously hypertensive rats. 2. Spontaneously hypertensive rats and Wistar-Kyoto rats were fed diets with three different Ca2+ contents, 0.1% (low-Ca2+ diet), 0.6% (normal-Ca2+ diet) and 4.0% (high-Ca2+ diet), between 6 and 20 weeks of age. At 20 weeks of age, the levels of erythrocyte Na+ efflux, as well as Na+ and K+ contents in erythrocytes, were measured. 3. On the low-Ca2+ diet, spontaneously hypertensive rats showed an enhancement of hypertension. Conversely, on the high-Ca2+ diet, they showed an attenuation of the increase in blood pressure. Spontaneously hypertensive rats had a lower erythrocyte Na+ content and increased activity of the Na+ pump at higher levels of dietary Ca2+. Passive Na+ permeability and Na+-K+ co-transport were similar in spontaneously hypertensive rats on the low-, normal- and high-Ca2+ diets. There were no significant differences in blood pressure and in Na+ pump activity in WKY on the three different diets. 4. It is concluded that dietary Ca2+ might affect the regulation of blood pressure in spontaneously hypertensive rats by changing the activity of Na+ pump in the cell membrane.

scholarly journals Continuous Electrocardiogram Reveals Differences in the Short-Term Cardiotoxic Response of Wistar-Kyoto and Spontaneously Hypertensive Rats to Doxorubicin

2009 ◽  
Vol 110 (1) ◽  
pp. 224-234 ◽  
Author(s):  
Mehdi S. Hazari ◽  
Najwa Haykal-Coates ◽  
Darrell W. Winsett ◽  
Daniel L. Costa ◽  
Aimen K. Farraj
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Short Term ◽  
Spontaneously Hypertensive ◽  
Wistar Kyoto

Metformin decreases plasma insulin levels and systolic blood pressure in spontaneously hypertensive rats

1994 ◽  
Vol 267 (4) ◽  
pp. H1250-H1253 ◽  
Author(s):  
S. Verma ◽  
S. Bhanot ◽  
J. H. McNeill
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Plasma Insulin ◽  
Metformin Treatment ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Insulin Levels ◽  
Plasma Insulin Levels ◽  
Wistar Kyoto

To determine the relationship between hyperinsulinemia and hypertension in spontaneously hypertensive rats (SHR), the antihyperglycemic agent metformin was administered to SHR and their Wistar-Kyoto (WKY) controls, and its effects on plasma insulin levels and blood pressure were examined. Five-week-old rats were started on oral metformin treatment (350 mg.kg-1.day-1, which was gradually increased to 500 mg.kg-1.day-1 over a 2-wk period). Metformin treatment caused sustained decreases in plasma insulin levels in the SHR (27.1 +/- 2.3 vs. untreated SHR 53.5 +/- 2.7 microU/ml, P < 0.001) without having any effect in the WKY (30.7 +/- 2.2 vs. untreated WKY 37.8 +/- 1.6 microU/ml, P > 0.05). The treatment did not affect the plasma glucose levels in any group. Metformin treatment also attenuated the increase in systolic blood pressure in the SHR (157 +/- 6.0 vs. untreated SHR 196 +/- 9.0 mmHg, P < 0.001) but had no effect in the WKY (134 +/- 3 vs. untreated WKY 136 +/- 4 mmHg, P > 0.05). Furthermore, raising plasma insulin levels in the metformin-treated SHR to levels that existed in the untreated SHR reversed the effect of metformin on blood pressure (189 +/- 3 vs. untreated SHR 208 +/- 5.0 mmHg, P > 0.05). These findings suggest that either hyperinsulinemia may contribute toward the increase in blood pressure in the SHR or that the underlying mechanism is closely associated with the expression of both these disorders.

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