Suppression of Plasma Renin by Atherogenic Levels of Serum Cholesterol in Rabbits

1973 ◽  
Vol 45 (4) ◽  
pp. 565-569
Author(s):  
D. J. Campbell ◽  
S. L. Skinner ◽  
A. J. Day
Keyword(s):  
Blood Pressure ◽  
Serum Cholesterol ◽  
Enzyme Inhibitors ◽  
Kinetic Studies ◽  
Plasma Renin ◽  
Renin Secretion ◽  
High Cholesterol Diet ◽  
Cholesterol Diet ◽  
High Cholesterol ◽  
Renin Substrate

1. Sixteen rabbits received either a normal or a high cholesterol diet over an 80-day period. 2. Diastolic blood pressure remained unchanged in each group. 3. Progressive suppression of plasma renin activity and concentration without change in renin substrate occurred in animals receiving the high cholesterol diet. 4. Kinetic studies excluded the mediation of enzyme inhibitors in this response and made probable a true suppression of renin secretion. 5. Commonly recognized influences seemed not to account for the findings and the possibility is raised of a dependence of renin secretion upon serum cholesterol. The effect occurs at the level of serum cholesterol found in man.

scholarly journals Vitamin B12 Inhibits Progression of Hypercholesterolemia and Atherosclerosis in Rabbits Fed a High Cholesterol Diet

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Salim Abou-Khalil ◽  
Ron Poulsen ◽  
Michael B. Stemerman ◽  
Sean Moore ◽  
Misbahuddin Zafar Alavi
Keyword(s):  
Vitamin B12 ◽  
Cholesterol Level ◽  
Serum Cholesterol ◽  
Serum Cholesterol Level ◽  
Pharmacological Intervention ◽  
High Cholesterol Diet ◽  
Cholesterol Diet ◽  
High Cholesterol ◽  
Baseline Serum ◽  
Group 4

The present study was undertaken to examine the effect of vitamin B12 on serum cholesterol levels and development of aortic atherosclerosis in New Zealand White male rabbits fed a high cholesterol diet. Twenty rabbits were divided into 4 groups matched for their baseline serum cholesterol values. Groups 1 and 2 received a normal diet, whereas groups 3 and 4 had cholesterol mixed with their chow. After 5 weeks, the serum cholesterol of groups 3 and 4 increased by approximately 12 fold compared to groups 1 and 2. At that point, vitamin B12 was administered in the drinking water (1000 micrograms/l) to rabbits in groups 2 and 4. At week 8, the Vitamin B12 dose was increased to 2400 micrograms/l for group 4. At 12 weeks into the study, rabbits in group 4 (high cholesterol diet plus vitamin B12) had a serum cholesterol level of 919 +/- 270 mg/dl while those of group 3 (high cholesterol diet) had a serum cholesterol level of 1417 +/- 250 mg/dl. At the end of the study, rabbit aortas were excised, fixed, and stained with fat-red-B, a dye for lipid. Comparison of the aortas of rabbits that received the lipid rich diet revealed that animals given additional vitamin B12 had significantly decreased surface area of fat deposition. These data suggest the potential role for vitamin B12 as a safe and inexpensive pharmacological intervention for the modification of the progression of human atherosclerosis.

Effects of low-dose ketanserin on atherosclerosis in rats and rabbits

2010 ◽  
Vol 88 (11) ◽  
pp. 1054-1060 ◽  
Author(s):  
Yong-Sheng Yu ◽  
He-Hui Xie ◽  
Ling Li ◽  
Shu-Wei Song ◽  
Ping Han ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Vitamin D ◽  
New Zealand ◽  
Treatment Group ◽  
Low Dose ◽  
Control Group ◽  
High Cholesterol Diet ◽  
Cholesterol Diet ◽  
High Cholesterol ◽  
New Zealand White Rabbits

The present study was designed to test the hypothesis that a small dose of ketanserin, which enhances baroreflex activity, prevents the early lesions of atherosclerosis. In experiment 1, baroreflex sensitivity (BRS) was measured in 31 spontaneously hypertensive rats (SHRs) in a conscious state using a computerized blood pressure monitoring system. Four weeks later, the rats were administered vitamin D3 and fed a high-cholesterol diet for 8 weeks to induce atherosclerosis. Then their hearts and aortae were removed for pathological examination. A negative correlation was found between BRS and the scores of coronary (r = –0.460, P < 0.01) and aortic atherosclerosis (r = –0.448, P < 0.05) in SHR. In experiment 2, SHRs were divided into 3 groups (n = 10 in each group) and received a dose of ketanserin of 0.3, 1.0, and 3.0 mg/kg (i.g.), respectively. At the smallest dose (0.3 mg/kg), ketanserin did not lower blood pressure but enhanced BRS. In experiment 3, SHRs were administered vitamin D3, fed a high-cholesterol diet, and simultaneously treated with low-dose ketanserin. The atherosclerosis scores of the treatment group were significantly lower than those of the control group (coronary score: 0.90 ± 0.14 vs. 1.76 ± 0.27, P < 0.05; aortic scores: 1.00 ± 0.39 vs. 2.18 ± 0.41, P < 0.05). In experiment 4, male New Zealand White rabbits were fed a high-cholesterol diet and treated with low-dose ketanserin at the same time. The atherosclerosis scores of the treatment group were significantly lower than those of the control group (aortic scores: 0.26 ± 0.20 vs. 0.60 ± 0.31, P < 0.05). In conclusion, the present study demonstrated, for the first time, that low-dose ketanserin prevented the development of atherosclerosis independent of its blood pressure lowering action in SHRs and New Zealand White rabbits at least in part via enhancement of arterial baroreflex function.

The effect of diabetes mellitus on aortic prostanoid synthesis and serum cholesterol levels in the rat fed a high cholesterol diet

Life Sciences ◽  
1990 ◽  
Vol 47 (6) ◽  
pp. 587-594 ◽  
Author(s):  
Stuart I. Myers ◽  
Lori Bartula ◽  
Mike Linzel ◽  
Tam Phan ◽  
Pa Jong Jung ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Serum Cholesterol ◽  
High Cholesterol Diet ◽  
Cholesterol Diet ◽  
High Cholesterol ◽  
Cholesterol Levels ◽  
Prostanoid Synthesis

The hypercholesterolaemic effect of caffeine in rats fed on diets with and without supplementary cholesterol

1978 ◽  
Vol 39 (2) ◽  
pp. 363-374 ◽  
Author(s):  
R. Fears
Keyword(s):  
Cholic Acid ◽  
Serum Cholesterol ◽  
Human Subjects ◽  
Experimental Period ◽  
High Cholesterol Diet ◽  
Cholesterol Diet ◽  
Stock Diet ◽  
High Cholesterol ◽  
Faecal Excretion ◽  
Hepatic Cholesterogenesis

1. The effect of caffeine (2.5 g/kg diet) on lipid metabolism was examined in rats fed on a stock (low-cholesterol) diet or on a cholesterol plus cholic acid-supplemented (high-cholesterol) semi-synthetic diet.2. When caffeine was included in the stock diet fed to rats for 7 d, there was a moderate but significant increase in the concentration of serum cholesterol compared to the levels observed in the control rats. This change can be accounted for by the increase that was observed in the rate of cholesterogenesis in the liver.3. After 25 d of caffeine in the stock diet, hepatic cholesterogenesis was still increased but the concentration of serum cholesterol was now the same as in the control rats. During the experimental period there was a progressive increase in the faecal excretion of neutral sterols in the rats receiving caffeine.4. When caffeine was added to a cholesterol plus cholic acid-supplemented diet, there was a marked increase in the concentration of serum cholesterol but hepatic cholesterogenesis was now reduced.5. Caffeine in the high-cholesterol diet appeared to delay, but probably did not reduce, the absorption of an oral dose of radio-labelled cholesterol. This conclusion was confirmed using rats which had not previously received either caffeine or cholesterol in the diet.6. When the effect of caffeine in the high-cholesterol diet was investigated during a 24 h period, an exacerbation of the hypercholesterolaemia was seen only at certain times.7. After a 4-month period of feeding rats on the caffeine-supplemented high-cholesterol diet, histological examination did not detect any damage to the heart and aorta.8. The metabolic regulations involved in the effects of caffeine in the two diets are discussed and the relevance of the present results to observations made with human subjects is considered.

scholarly journals The fat and protein fractions of freshwater clam (Corbicula fluminea) extract reduce serum cholesterol and enhance bile acid biosynthesis and sterol excretion in hypercholesterolaemic rats fed a high-cholesterol diet

2010 ◽  
Vol 105 (4) ◽  
pp. 526-534 ◽  
Author(s):  
Takeshi Chijimatsu ◽  
Miki Umeki ◽  
Yuji Okuda ◽  
Koji Yamada ◽  
Hiroaki Oda ◽  
...  
Keyword(s):  
Bile Acid ◽  
Serum Cholesterol ◽  
Corbicula Fluminea ◽  
Protein Fractions ◽  
High Cholesterol Diet ◽  
Cholesterol Diet ◽  
High Cholesterol ◽  
Cholesterol Levels ◽  
Neutral Sterols ◽  
Fat Fraction

We investigated whether the fat and protein fractions of freshwater clam (Corbicula fluminea) extract (FCE) could ameliorate hypercholesterolaemia in rats fed a high-cholesterol diet. We also explored the mechanism and the components that exert the hypocholesterolaemic effect of FCE. The doses of the fat and protein fractions were equivalent to those in 30 % FCE. The fat and protein fractions of FCE, two major components of FCE, significantly reduced the serum and hepatic cholesterol levels. The fat fraction more strongly reduced serum cholesterol levels than the same level of total FCE. The excretion of faecal neutral sterols increased in rats fed the total the FCE and the fat fraction of FCE. On the other hand, faecal bile acid levels were greater in rats fed the total FCE and the fat and protein fractions of FCE than in control animals. The hepatic gene expression of ATP-binding cassette transporter G5 and cholesterol 7α-hydroxylase was up-regulated by the administration of the total FCE and both the fat and protein fractions of FCE. These results showed that the fat and protein fractions of FCE had hypocholesterolaemic properties, and that these effects were greater with the fat fraction than with the protein fraction. The present study indicates that FCE exerts its hypocholesterolaemic effects through at least two different mechanisms, including enhanced excretion of neutral sterols and up-regulated biosynthesis of bile acids.

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