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Biomedical subjects

L K Bale

Publications and source records attributed to L K Bale.

22 records · Page 2Linked to original sources

Effect of neonatal modulation of cholesterol homeostasis on subsequent response to cholesterol challenge in adult guinea pig.

Experiments were designed to study whether or not the mechanism of handling dietary cholesterol in adulthood can be modulated by the manipulation of cholesterol homeostasis during neonatal period. The effects of enhancing cholesterol degradation (cholestyramine feeding), high dietary cholesterol intake, and early weaning during neonatal period of guinea pigs on their subsequent plasma cholesterol levels and the response to dietary cholesterol challenged in adulthood were investigated. Pretreatment of neonatal guinea pigs with cholestyramine resulted in (a) a lower plasma cholesterol level, (b) an increased excretion rate of fecal bile acids and total steroids, (c) an expanded bile acid pool, (d) an increased activity of cholesterol 7 alpha-hydroxylase, and (e) no change in the hepatic 3-hydroxy-3-methylglutaryl coenzyme A (CoA) reductase activity when challenged with cholesterol in adulthood. Cholesterol pretreatment during neonatal period resulted in (a) no alteration in the plasma cholesterol level, (b) no alteration in the fecal excretion of steroids, or (c) no alteration in the cholesterol 7 alpha-hydroxylase activity when they were challenged with a high cholesterol diet. Early weaning did not influence the fecal excretion of steroids or cholesterol 7 alpha-hydroxylase activity but resulted in a slight decrease in the hepatic 3-hydroxy-3-methylglutaryl-CoA reductase activity when they were challenged with a high cholesterol diet. These results suggest that stimulation of cholesterol catabolism rather than cholesterol feeding or early weaning during neonatal period can influence the response to dietary cholesterol challenge in adulthood.

Aging↗

Effect of enhancement of cholesterol degradation during neonatal life of guinea pig on its subsequent response to dietary cholesterol.

The effect of feeding cholestyramine to neonatal guinea pigs on their subsequent plasma cholesterol levels and response to dietary cholesterol were studied. Male neonatal guinea pigs were suckled for 6 days. One group was maintained on a 1.1% cholestyramine diet for 6 weeks and the control group weaned normally. Both groups of guinea pigs were then fed a standard diet of Guinea Pig Chow for 6 weeks. During the standard diet period bile acid and neutral sterol excretion rates were significantly higher in the group previously treated with cholestyramine than the control group despite the similarity in plasma cholesterol levels. When both groups of guinea pigs were subjected to a 0.5% cholesterol diet for 4 weeks, plasma cholesterol levels were significantly lower in the group previously treated with cholestyramine than the control group. The plasma cholesterol levels continued to be significantly lower in the group previously treated with cholestyramine after an additional four weeks on standard diet. These results suggest that stimulation of cholesterol catabolism in the neonatal period can influence the subsequent response to dietary cholesterol.

Animals↗

Bile acid and cholesterol excretion in the pregnant guinea pig: studies on the hypercholesterolemia of pregnancy.

The relationship of bile acid and cholesterol excretion to changes in plasma cholesterol during pregnancy were studied in guinea pigs. Plasma cholesterol level increased in the first trimester of pregnancy, reached to a peak during the second trimester and decreased in the third trimester reaching the lowest level at one week prior to parturition. Cholesterol level returned to the control level after parturition. Plasma triglyceride level followed a similar trend attaining peak values at second trimester and gradually returned to the control level at the third trimester of pregnancy. Bile acid and total sterol excretion were significantly higher in guinea pigs during the last phase of pregnanccy while they remained unchanged during early stage of pregnancy.

Animals↗

Regional differences in cholesterol content of aorta in response to experimental coarctation in spontaneously atherosclerosis-susceptible pigeons.

The effect of experimental coarctation of the aorta at a site above the coeliac bifurcation (site of occurance of spontaneous atherosclerotic lesions) in White Carneau pigeons was examined. Cholesterol content of the aorta in the site where spontaneous atherosclerosis usually occurs (coeliac bifurcation = lesion site) was decreased in pigeons with aortic coarctation. On the other hand, in the region proximal to the site of coarctation which is usually free of atherosclerotic events cholesterol accumulation was increased. A decrease in percent composition of oleic acid (the major fatty acid which increases during atherosclerosis) was noted in the lesion site. These studies have shown regional differences in response of aorta to experimental coarctation in spontaneously atherosclerotic-susceptible pigeons and suggest that lowering of blood pressure at lesion site might decrease cholesterol accumulation and perhaps might retard subsequent atherogenic process.

Animals↗