Effects of chronic ethanol consumption and pair feeding on rates of protein synthesis and nucleic acid composition in rat tibia.

An investigation was made into the chronic effects of ethanol feeding on bone (represented by the tibia). Treated rats were fed a liquid diet containing ethanol as 36% of total calories, and controls were pair-fed identical amounts of the same diet in which ethanol was substituted by isocaloric glucose. Bone DNA and RNA contents in ethanol-fed rats were not significantly different from glucose-fed controls at days 3, 7, 14, 28 and 42 of treatment. Fractional rates of bone protein synthesis were measured with [43H]-phenylalanine. At 3, 7, 14, 28 and 42 days, ethanol feeding had no effect on free and protein-bound specific radioactivities, nor on fractional or absolute rates of protein synthesis. Synthesis rates relative to RNA (RNA activities) and DNA (cellular efficiencies) were also not significantly altered by ethanol feeding at these time points. Comparisons were made between rats fed a standard solid laboratory diet ad libitum (i.e. normal rats), and those fed restricted amounts of glucose-containing liquid diet (i.e. dietary-restricted rats) for 42 days. In normal rats, there was an increase in tibial mass and accretion of total collagen content, but in dietary-restricted rats, this accretion was markedly impaired. Furthermore, whilst RNA and DNA contents were increased in tibia of normal rats, the contents of these nucleic acids were reduced in bones of dietary restricted rats. Fractional rates of bone protein synthesis in normal rats were unaltered after 42 days, but reduced by feeding the control liquid diet in restricted amounts.(ABSTRACT TRUNCATED AT 250 WORDS)