Dietary regulation of the activities of ornithine decarboxylase and S-adenosylmethionine decarboxylase in rats.
The purpose of this study was to investigate the dietary regulation of the two key enzymes in polyamine biosynthesis, ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMDC) in rat tissues. Either an amino acid mix (patterned after casein), a complete diet or several dietary components were administered to fasting rats by gastric tube. Rats were killed at specific time intervals, over a 12-hour period, and the activities of ODC and SAMDC were measured in the following tissues: liver, kidney, small intestine, brain and skeletal muscle. The amino acid mix, as well as the complete diet, elicited rapid and substantial increases in ODC and SAMDC activities in liver, kidney and intestine. In brain and muscle SAMDC activity only was increased. Studies with actinomycin D showed that SAMDC and ODC activities are regulated at transcription. The mechanism eliciting the observed increases in enzyme activities is postulated to be the influx of amino acids into cells rather than the influence of hormones secreted in response to dietary stimulation.
D012437:Adenosylmethionine Decarboxylase / Q000378:metabolism*; D000596:Amino Acids / Q000008:administration & dosage* / Q000494:pharmacology; D000818:Animals; D002262:Carboxy-Lyases / Q000378:metabolism*; D003609:Dactinomycin / Q000494:pharmacology; D004032:Diet; D004305:Dose-Response Relationship, Drug; D005260:Female; D007441:Intubation, Gastrointestinal; D009955:Ornithine Decarboxylase / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D014018:Tissue Distribution
D000596:Amino Acids; D003609:Dactinomycin; D002262:Carboxy-Lyases; D009955:Ornithine Decarboxylase; D012437:Adenosylmethionine Decarboxylase