Effects of chronic ethanol treatment on the in vitro biosynthesis of pro-opiomelanocortin and its posttranslational processing to beta-endorphin in the intermediate lobe of the rat pituitary.
Chronic treatment of rats with 15% (vol/vol) ethanol in tap water as their only source of liquid over a period of 3 weeks resulted in a strong decrease by almost 50% in tissue levels and in vitro release of immunoreactive beta-endorphin of the neurointermediate pituitary. Moreover, the in vitro incorporation of [3H]phenylalanine into peptides of the neurointermediate pituitary, immunoprecipitable with beta-endorphin antiserum, was found to be decreased by more than 30%. Analysis of beta-endorphin-related peptides on sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that chronic ethanol treatment reduced the in vitro biosynthesis of the beta-endorphin precursor pro-opiomelanocortin. This ethanol-induced effect was combined with a retardation in the time course of the posttranslational processing of the precursor into beta-endorphin. Thus, chronic ethanol treatment may influence the activity of enzymes which process the opioid peptide precursor pro-opiomelanocortin, leading to a decreased formation of the final secretory product beta-endorphin.
D000818:Animals; D004723:Endorphins / Q000096:biosynthesis* / Q000235:genetics; D000431:Ethanol / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D010649:Phenylalanine / Q000378:metabolism; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism*; D010908:Pituitary Hormones, Anterior / Q000096:biosynthesis* / Q000235:genetics; D011333:Pro-Opiomelanocortin; D011498:Protein Precursors / Q000096:biosynthesis* / Q000235:genetics; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D014316:Tritium; D001615:beta-Endorphin
D004723:Endorphins; D010908:Pituitary Hormones, Anterior; D011498:Protein Precursors; D014316:Tritium; D000431:Ethanol; D010649:Phenylalanine; D001615:beta-Endorphin; D011333:Pro-Opiomelanocortin