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Biomedical subjects

G Y Sun

Publications and source records attributed to G Y Sun.

At least 145 records · Page 8Linked to original sources
PubMed1979

Effect of ethanol on cholesteryl ester hydrolases in adrenal.

An assay of cholesteryl ester hydrolase activity of microsomes from guinea pig adrenal indicated maximal activity at pH at pH 4.0 and 5.5. When ethanol was added to the microsomes, these enzymes showed differences in response with increasing ethanol concentration. Rats administered 15% ethanol as drink for 4--5 months showed a small (20%) increase in cholesteryl ester hydrolase (pH 4.0) activity in adrenal as compared to controls. However, a 50% decrease in cholesteryl ester hydrolase activity resulted when rats were administered ethanol by intragastric tubing technique (15 days) as compared to controls treated similarly with saline. The decrease in cholesteryl ester hydrolase activity was correlated with an increase in cholesteryl ester level in serum. In a different study, rats intubated with an acute dose of ethanol showed an increase in adrenal cholesteryl ester hydrolase activity as early as 1 hr after administration. This effect seemed to last for about 24 hr before activity returned to control level. It is concluded that different modes of ethanol administration to rats may elicit a change in cholesteryl ester hydrolase activity in the adrenal. An increase in cholesteryl ester hydrolase activity may be related to an increase in steroidogenic activity and activation of adrenocortical function.

Adrenal Glands↗
PubMed1979

Effect of chronic ethanol administration on phospholipid acyl groups of synaptic plasma membrane fraction isolated from guinea pig brain.

Guinea pigs were induced chronic alcoholism with a liquid diet containing 5% (w/v) ethanol. There was no apparent change in acyl group composition in the myelin lipids; however, acyl group changes were observed in the phosphoglycerides of synaptic plasma membranes (SPM). In general, acyl group changes are related to a decrease in the proportion of monoenes in both choline and ethanolamine phosphoglycerides and an increase in polyenes (15%) in the ethanolamine phosphoglycerides. The changes observed may be associated to the increased membrane-dependent transport activities observed after chronic ethanol treatment.

Alcoholism↗
PubMed1979

The effect of chronic ethanol administration on myelin lipids.

Myelin was isolated from the brain stem region of rats which were administered chronically with ethanol either through intragastric tubing (8gm/kg) for 3 weeks or by giving a 15% ethanol ad lib as drink for 1 year. The protein, phospholipid and cholesterol content and the acyl group composition of major phosphoglycerides of myelin were examined. Based on the protein content, there was less myelin isolated from the chronic alcoholic brain samples as compared to controls. Intrinsic changes in membrane components were observed. The phospholipid to protein ratio of myelin was approximately 20% lower in the group subjected chronically to ethanol by drink and 10% lower in the group given ethanol through intubation technique. The cholesterol to protein ratio was also lower in the group given ethanol as drink but the intubated group was not different from controls. Changes in phosphoglyceride acyl group composition were also observed. In general, there was an increase in the proportions of 16:0, 18:0 and 18:1 and a decrease in 20:1, 20:4 and 22:6. The acyl group changes reflected an increase in cellular phospholipase A2 or a decrease in chain desaturation and elongation activity due to chronic ethanol administration. These changes are also reflective of degenerative changes possibly associated with demyelination.

Alcoholism↗
PubMed1978

Vitamin E, antioxidants and lipid peroxidation in experimental atherosclerosis of rabbits.

The purpose of this study was to evaluate the effects of large amounts of dietary vitamin E and butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) in rabbits fed a low-cholesterol, atherogenic diet, and to seek for evidence of lipid peroxidation in the atherosclerotic lesions. Rabbits were fed a purified atherogenic diet, containing butter or the basal diet supplemented with either 1.0% of vitamin E or 0.1% each of BHA and BHT for periods up to 3 years; a negative control group was fed the basal diet with corn oil replacing butter. Aortic and coronary atherosclerosis were more frequent and extensive in rabbits fed either the basal diet or the basal diet supplemented with BHA and BHT than in rabbits fed either the basal diet supplemented with vitamin E or the negative control diet. Dietary vitamin E inhibited atherogenesis by preventing hypercholesterolemia. No evidence of lipid peroxidation was detected in the arterial lesions.

Animals↗
PubMed1978

Dihydroergotoxine and ethanol: physiological and neurochemical variables in male mice.

The residual effects of dihydroergotoxine mesylate (DHET: active substance of Hydergine), ethanol, and DHET + ethanol were investigated in aging male mice. Prolonged alcohol or DHET consumption was found to prolong hexobarbital sleeping time and increase oxygen consumption. Administration of alcohol combined with DHET inhibited the ability of each drug to prolong hexobarbital sleeping time and increase oxygen consumption. There were no significant differences between groups in forebrain synaptosomal (Na+-K+) adenosine- triphosphatase and acetylcholinesterase activity or cerebellar protein, DNA and RNA content. The relative proportion of phospholipid to protein in isolated myelin of the medulla was significantly reduced, whereas the sphingomyelin content of total phospholipid was highest in alcohol-treated mice. Conocomitant treatment of mice with alcohol combined with DHET prevented the physiological and neurochemical changes caused by alcohol and, in some cases, DHET, administered alone.

Acetylcholinesterase↗
PubMed1978

The effects of chronic ethanol administration on acyl group composition of mitochondrial phospholipids from guinea pig adrenal.

The acyl groups of diacyl-glycerophosphocholine1 (GPC) and diacyl-glycerophosphoethanolamine (GPE) in guinea pig adrenals are comprised mainly of 16:0, 18:0, 18:1, 18:2 and 20:4(n-6) with only trace amounts of the longer chain polyunsaturated fatty acids. There was an increase in the proportions of 18:2 and a decrease in the 20:4(n-6) of diacyl-GPC and diacyl-GPE with respect to chronic ethanol administration. Acyl group changes were more obvious in diacyl-GPC than in diacyl-GPE. It is conceivable that these changes may lead to an alteration of other membrane transport activities as well as functions of the adrenal gland.

Adrenal Glands↗
PubMed1978

Effects of ethanol and dihydroergotoxine on mouse brain myelin components.

The effects of prolonged consumption of ethanol, dihydroergotoxine (Hydergine) and Hydergine-plus-ethanol on brain myelin components isolated from the medulla oblongata of mouse brain were examined. Based on protein content, the amount of myelin isolated from the brain tissue was not different with regard to the various treatments. However, there was a significant decrease (20%) in myelin phospholipid and cholesterol to protein ratios in the ethanol group as compared to controls and the Hydergine-treated group. On the contrary, the Hydergine and Hydergine-ethanol groups had higher cholesterol to phospholipid ratios than controls. In spite of the changes in membrane components, little change in acyl group composition of the phosphoglycerides was found in myelin.

Aging↗
PubMed1977

Metabolism of arachidonate and stearate injected simultaneously into the mouse brain.

The metabolism of a polyunsaturated and a saturated fatty acid in brain membrane phosphoglycerides was examined by injecting simultaneously a mixture of 14C-arachidonate and 3H-stearate into the mouse brain and isolating the microsomal and synaptosomal fractions at 1-40 min after injections. Both types of labeled fatty acids were utilized more readily in the microsomal than the synaptosomal fractions in brain. However, labeled arachidonate was incorporated more rapidly into membrane phosphoglycerides than was stearate. In both subcellular fractions, the relative specific radioactivity (3H and 14C) of diacyl-glycerophosphorylinositol (diacyl-GPI) was higher than other types of phosphoglycerides such as diacyl-glycerophosphorylcholine (diacyl-GPC) and diacyl-glycerophorylethanolamine (diacyl-GPE). Furthermore, the apparent rates of incorporation of radioactivity into diacyl-GPI was more rapid for the 14C-arachidonate than for the 3H-stearate. Results of the experiment have demonstrated obvious differences in metabolism between stearate and arachidonate in brain. The more rapid transfer of arachidonate to diacyl-GPI is probably due to the presence of an acyl transferase system specially active for the transfer of arachidonyl groups to diacyl-GPI.

Animals↗
PubMed1977

The effect of chronic ethanol administration on arachidonyl transfer to 1-acyl-glycerophosphorylcholine in rat brain synaptosomal fraction.

Enzymatic transfer of arachidonate to synaptosomal diacyl-GPC in a group of rats (n=14) administered 30% ethanol by intragastric intubation for 21 days was 24% higher than controls (n=5) (P less than 0.05). No apparent difference in enzymic activity was observed with respect to different periods of withdrawal (8-24 hrs). The acyl transferase activity in another group of rats (n=5) which were given 15% ethanol as the sole drinking source for 13 months was 58% higher than controls (P less than 0.025). The increase in acyl transferase activity with respect to the two types of chronic ethanol administration may be due to an adaptive mechanism in brain to facilitate the increase in membrane transport activities which are known to occur under the influence of ethanol.

Acyltransferases↗