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

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.

1979 ◽  
Vol 42 (2) ◽  
pp. 209-216 ◽  
Author(s):  
D. G. Oakenfull ◽  
Dorothy E. Fenwick ◽  
R. L. Hood ◽  
D. L. Topping ◽  
R. L. Illman ◽  
...  

1. The effects of feeding isolated saponins on plasma lipid concentrations and on concentrations of biliary and faecal bile acids and neutral sterols were studied in the rat.2. The animals were given one of four diets, i.e. a standard low-cholesterol synthetic diet, the diet+10 g saponins/kg, the diet+10 g cholesterol/kg, the diet+10 g cholesterol+10 g saponins/kg.3. Saponins partially reversed the hypercholesterolaemia caused by the high-cholesterol diet and increased both the rate of bile acid secretion and the faecal excretion of bile acids and neutral sterols. The proportionate contribution of the primary bile acids (particularly chenodeoxycholic) to faecal excretion was also increased by saponins.4. The results are discussed in relation to the hypothesis that saponins act by inducing the adsorption of bile acids by dietary fibre.


2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Salim Abou-Khalil ◽  
Ron Poulsen ◽  
Michael B. Stemerman ◽  
Sean Moore ◽  
Misbahuddin Zafar Alavi

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.


Life Sciences ◽  
1990 ◽  
Vol 47 (6) ◽  
pp. 587-594 ◽  
Author(s):  
Stuart I. Myers ◽  
Lori Bartula ◽  
Mike Linzel ◽  
Tam Phan ◽  
Pa Jong Jung ◽  
...  

1973 ◽  
Vol 45 (4) ◽  
pp. 565-569
Author(s):  
D. J. Campbell ◽  
S. L. Skinner ◽  
A. J. Day

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.


2010 ◽  
Vol 105 (4) ◽  
pp. 526-534 ◽  
Author(s):  
Takeshi Chijimatsu ◽  
Miki Umeki ◽  
Yuji Okuda ◽  
Koji Yamada ◽  
Hiroaki Oda ◽  
...  

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.


1988 ◽  
Vol 15 (8) ◽  
pp. 1693-1697
Author(s):  
Tetsuto KANZAKI ◽  
Junji KOBAYASHI ◽  
Naoko WATANABE ◽  
Norihiro SASAKI ◽  
Shunichi MURANO ◽  
...  

1995 ◽  
Vol 73 (5) ◽  
pp. 701-710 ◽  
Author(s):  
Michihiro Fukushima ◽  
Masuo Nakano

The effect of a probiotic composed ofBacillus, Lactobacillus, Streptococcus, SaccharomycesandCandidaspecies (each at 107–8colony-forming units (cfu)/g rice bran), given at a level of 150 g/kg diet for 6 weeks, on lipid metabolism was examined in the faeces, serum and liver of male rats. Liver weight decreased 35% in the rats fed on a high-fat, high-cholesterol diet containing the probiotic. Total cholesterol concentration in the serum was significantly lower in the probiotic group than in the control group throughout the experimental period in rats fed on the high-fat, high-cholesterol diet, and HDL-cholesterol concentration was significantly higher (P< 0·05) in the probiotic group than in the control group which was fed for the 6 week experimental period on a basal diet. The serum VLDL + IDL + LDL cholesterol concentrations in the probiotic groups were reduced compared with those of the corresponding control groups. The probiotic groups fed on the high-fat, high-cholesterol diet and the basal diet had lower hepatic cholesterol concentrations than did the corresponding control groups (P< 0·05). Hydroxymethylglutaryl coenzyme A reductase (NADPH) (EC. 1.1.1.34) activity in the liver was lower in rats fed on the high-fat, high-cholesterol diet with the probiotic. The neutral and acidic steroid concentrations in faeces were higher in the probiotic group than in the control group fed on the high-fat, high-cholesterol diet.Escherichia colidecreased andBifidobacteriumandEubacteriumincreased in the faecal microflora of rats fed on the dietary probiotic.Lactobacillusin the probiotic groups was higher than that in the control groups. The present study shows that the probiotic promotesBifidobacteriumandEubacteriumin the faecal microflora, and reduces cholesterol levels in the serum and liver of rats.


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