title: Studies on the effects of chronic ethanol ingestion on the properties of rat brain ribosomes.
abstract: Previous observations have demonstrated decreased in vivo and in vitro protein synthesis by brain ribosomal systems following long-term ethanol ingestion. For further investigation of the properties of brain ribosomes, the 40S and 60S ribosomal subunits were successfully isolated from control and chronic 10% ethanol-drinking rats. For a successful dissociation of ribosomes into subunits NH4Cl, puromycin and a high-salt treatment at 10 degrees C were essential with a critical concentration of Mg2+ since ribosomes could not be resolved at less than 7 mM Mg2+. Analysis of the A260 profile of the subunits on the sucrose gradients showed no significant differences between the control and ethanol-ingesting groups. Studies on 3H-labeled ribosomes following in vivo RNA labeling showed correspondence of the radioactive profiles from the incorporation of [5(-3) H) orotic acid into RNA with the sucrose gradient absorbance profile of 60S and 40S ribosomal subunits. Furthermore, active reassociation of both subunits occurred at 37 degrees C as demonstrated by the increased [14 C]-phenylalanine incorporation in the presence of poly(U). Results further showed that the poly(U)-dependent [14C]phenylalanine incorporation was significantly reduced by the subunits from the ethanol-ingesting animals. These findings suggest that long-term ingestion of ethanol caused functional changes in the properties of brain ribosomes, specifically on the reassociation process of the two subunits.
mesh_terms: D000428:Alcohol Drinking; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D002458:Cell Fractionation; D002499:Centrifugation, Density Gradient; D004305:Dose-Response Relationship, Drug; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D009963:Orotic Acid / Q000378:metabolism; D010649:Phenylalanine / Q000378:metabolism; D011072:Poly U / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011691:Puromycin / Q000494:pharmacology; D012335:RNA, Ribosomal / Q000378:metabolism; D051381:Rats; D012269:Ribosomal Proteins / Q000378:metabolism; D012270:Ribosomes / Q000187:drug effects* / Q000378:metabolism
chemical_list: D012335:RNA, Ribosomal; D012269:Ribosomal Proteins; D011072:Poly U; D010649:Phenylalanine; D011691:Puromycin; D009963:Orotic Acid; D008274:Magnesium; D011188:Potassium