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Biomedical subjects

J Yudkin

Publications and source records attributed to J Yudkin.

At least 55 records · Page 3Linked to original sources
PubMed1980

Composition and biosynthesis of glomerular basement membrane in rats fed diets rich in sucrose.

1-month-old Sprague-Dawley rats were fed synthetic diets containing 55% sucrose (SU) or starch (ST) as the sole source of carbohydrate for 2, 3 or 8 months. Both the ST and SU fed rats gained weight normally, but SU fed rats had enlarged kidneys. A higher yield of glomerular basement membrane (GBM) was recovered from 9-month-old SU rats. An increase in the hydroxylated amino acid content was found in GBM prepared from SU fed rats and the glycine content was also higher. The increase in the hydroxylation of lysine was accompanied by increased glycosylation and there was 30% more Glc-Gal-Hyl present in GBM from 9-month-old SU rats. GBM was solubilised with sodium dodecyl sulphate (SDS) and 2-mercaptoethanol and subjected to electrophoresis on 5% polyacrylamide gels. There was an apparent fall in the intensity of the bands with molecular weights greater than 200,000 and a concomitant rise in low molecular weight components (50,000-100,000) in GBM from 4-month-old SU rats. These differences between ST and SU membrane were accentuated when the membranes from 9-month-old rats were compared. No significant differences were found in the glucosyl transferase activities of renal cortical homogenates prepared from 3-month-old SU and ST rats, but the activities in SU rats were significantly higher at 4 and 9 months. The feeding of SU-rich diets to rats induces a number of biochemical changes in the kidney which are similar to those found in diabetes. The feeding of SU diets provides a useful animal model with which to study the effect of dietary carbohydrate on renal GBM. SU should not be included in diets fed to diabetic rats because of the similarity of some of its effects and those seen in chemically induced diabetes.

Amino Acids↗
PubMed1979

Influence of different dietary carbohydrates on liver and plasma constituents in rats adapted to meal feeding.

Male Sprague-Dawley rats were given in one experiment diets with starch or sucrose and in a second experiment diets with glucose or fructose. In each experiment, one group of 5 rats was fed ad libitum and five other groups fed a 3-hour meal each day. After 36 days, one group of the meal-fed rats was killed when the meal was due, and the other groups at intervals after the beginning of the meal. The group fed ad libitum was killed the next day after 21 h fasting. Meal feeding led to a smaller food intake and a smaller gain in weight, and a lower blood concentration of triacylglycerol. The diets with sucrose or fructose produced heavier livers and kidneys than did those with starch or glucose. The consumption of the meal led also to a temporary increase in the weight of the liver. The weight of the kidney, however, did not change in rats given starch or gluocse, but fell in rats given sucrose or fructose. Meal consumption was also followed by an increase in the concentration of liver glycogen, irrespective of the nature of the dietary carbohydrate. The concentration of plasma fatty acids was affected differently by meals containing the different carbohydrates, the extremes being a continuing fall with starch and no change with fructose. The concentration of triacyglycerol was increased by sucrose or fructose after the presentation of the meal. The concentration of blood glucose rose and then fell when the meal contained starch or glucose, but fell and then rose when it contained sucrose, and especially when it contained fructose. The concentration of insulin in meal-fed rats receiving sucrose was higher than that of rats receiving starch, both before and after the meal. This difference was not seen in rats fed ad libitum. The results indicate that the effects of meal feeding, or of sucrose or fructose, are not additive.

Animals↗
PubMed1979

The avoidance of sucrose by thiamine-deficient rats.

Rats were fed carbohydrate-free diets without thiamine. Sucrose was offered separately, either before the thiamine was removed, or when it was removed, or at varying periods after it was removed. In the absence of dietary thiamine, sucrose consumption began at a high level, but was then reduced. Thereafter, death due to thiamine deficiency followed at intervals that varied from 4 weeks to 12 months. Survival was shortest in those rats that ate sucrose in largest amounts or at shortest intervals; survival was longest in those rats that avoided sucrose altogether for long periods. Sex or age did not appear to affect survival. The results are interpreted as demonstrating a conflict between the avoidance of sucrose so as to avoid the unpleasant symptoms of thiamine deficiency, and the consumption of sucrose so as to obtain the pleasure of its high palatability.

Age Factors↗
PubMed1978

Dietary factors in arteriosclerosis: sucrose.

Epidemiological studies show that coronary heart disease is more common in wealthier countries than in poorer. Such studies cannot, however, isolate which of the dietary or nondietary characteristics of affluence help to cause the disease; they provide only clues that need to be subjected to experimental study. Experiments should be designed on the basis of their ability to produce the multiple abnormalties associated with coronary heart disease (CHD) and not only hypercholesterolemia. They should also explain the association of CHD with obesity, diabetes mellitus, cigarette smoking, and physical inactivity. These considerations suggest that the underlying abnormality that produces CHD is a disturbed hormonal balance. Experiments have shown that a high consumption of sucrose produces not only the wide range of abnormalities seen in CHD but also an increased blood concentration of insulin and cortisol. Since a low intake of sucrose confers many other health benefits, it is a more logical dietary recommendation than that of substituting polyunsaturated fat for saturated fat.

Arteriosclerosis↗