Stephen Filus

Wake Forest University, Winston-Salem, North Carolina, United States

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Publications (3)9.74 Total impact

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    ABSTRACT: Male Sprague-Dawley rats were maintained for 31 days on a liquid diet containing 36% of calories as ethanol. Pair-fed controls were administered a similar diet, but with maltose-dextrin isocalorically substituted for ethanol. A phospholipid analysis has been carried out in liver microsomes and mitochondria isolated from the two groups of animals. The phospholipid phosphorus/protein ratio was not significantly different in the organelles of the ethanol-fed animals as compared to the same organelles of liquid diet controls, which indicates that ethanol feeding did not influence the total phospholipid content of microsomes and mitochondria. The phospholipid distribution within organelles was not changed, except for a significant increase in the phosphatidylinositol content of microsomes from ethanol-fed animals. The fatty acid compositions of both microsomal and mitochondrial phospholipids were significantly altered by ethanol feeding. In microsomes from ethanol-fed rats, palmitic acid levels were lowered in the total phospholipid fraction, phosphatidylcholine and phosphatidylethanolamine; oleic acid levels were elevated in microsomal phosphatidylethanolamine. In mitochondria from ethanol-fed animals, palmitic and arachidonic acid were lowered in phosphatidylcholine and phosphatidylethanolamine. Oleic and linoleic acid were elevated in the same phospholipids. In contrast, linoleic acid levels in cardiolipin were depressed significantly. These alterations in the fatty acid composition are suggestive of ethanol-induced changes in fatty acid desaturation activities.
    No preview · Article · Sep 1982 · Biochimica et Biophysica Acta
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    ABSTRACT: Male rats were administered an ethanol-containing diet for 31 days during which time they demonstrated fatty liver. Mitochondria and submitochondrial particles were prepared from their livers (ethanol mitochondria, ethanol submitochondrial particles) and from their pair-fed partners (control mitochondria, control submitochondrial particles). The H+/coupling site ratio was not significantly different in ethanol and control mitochondria with succinate as electron donor. A 13% decrease in the H+/coupling site ratio was observed in ethanol mitochondria, however, when β-hydroxybutyrate was used as substrate. The rate of ATP-Pi exchange was decreased significantly in both ethanol mitochondria and submitochondrial particles as compared to control preparations. These observations demonstrate ethanol-elicited decreases in energy conservation in the site I region of the electron transport chain and in the activity of the ATP synthetase complex.
    No preview · Article · May 1982 · Biochemical and Biophysical Research Communications
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    ABSTRACT: Male rats developed fatty liver after being fed an ethanol-containing diet for 31 days. Liver mitochondria from these animals (ethanol mitochondria) catalyzed ATP synthesis at a slower rate than did mitochondria from pair-fed control rats (control mitochondria). Furthermore, ATP translocation was decreased in ethanol mitochondria and parameters influencing such were investigated. Several experiments indicated that ADP uptake into ethanol mitochondria is not decreased due to inhibition of the adenine nucleotide translocase by either long chain acyl CoA derivatives or unesterified fatty acids. Analyses of endogenous adenine nucleotides in ethanol mitochondria revealed lower ATP concentrations, but no decrease in total adenine nucleotides. In experiments where endogenous ATP was shifted to higher concentrations by incubation with BSA, the rate of ADP translocation was increased, with a linear correlation being observed between endogenous ATP concentrations and the rate of ADP translocation. The depressed ATP concentration in ethanol mitochondria suggests that the ATP synthetase complex is replenishing endogenous ATP at a slower rate. A decrease in the rate of ATP synthesis in ethanol mitochondria is sufficient to explain the decreased ADP translocation.
    No preview · Article · Feb 1980 · Pharmacology Biochemistry and Behavior