title: Ornithine decarboxylase and polyamines in liver and kidneys of rats on cyclical regimen of protein-free and protein-containing diets. Relationship to deoxyribonucleic acid synthesis in liver.
abstract: 1. The activity of ornithine decarboxylase in the liver and kidneys of rats maintained on a cyclical regimen of protein-free and protein-containing diets was investigated. There was a daily activation of the enzyme in response to the feeding of protein after 3 days feeding of protein-free diet. 2. The activation of ornithine decarboxylase in the liver and kidneys of rats re-fed on protein was demonstrable throughout 16 cycles of alternating 3-day periods of protein-free and protein-containing diets. The magnitude of the activation in the kidneys diminished from 20-fold stimulation in the first cycle to 5-fold stimulation (compared with animals fed with protein-free diet) in the later cycles of protein re-feeding. The activation of the enzyme in liver was decreased from 20-fold stimulation in the first cycle to approx. 10-fold stimulation in later cycles. 3. The concentration of spermidine was increased by approx. 50% in the liver of animals during cycling from protein-free to protein-containing diets. Spermine was unchanged, and putrescine was maintained at a low concentration approx. one-fifth to one-tenth that of spermidine after protein re-feeding. 4. The incorporation of [(3)H]thymidine into liver DNA was increased 10-fold in animals re-fed with protein compared with animals receiving protein-free diets. 5. The activation of ornithine decarboxylase by re-feeding of protein was inhibited 90% by the injection of propane-1,3-diamine during re-feeding. The stimulation of DNA synthesis was inhibited 60% by multiple injections of propane-1,3-diamine during the re-feeding of protein.
mesh_terms: D000818:Animals; D002262:Carboxy-Lyases / Q000378:metabolism*; D004247:DNA / Q000096:biosynthesis; D003959:Diamines / Q000494:pharmacology; D004044:Dietary Proteins; D007668:Kidney / Q000201:enzymology / Q000378:metabolism*; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D009955:Ornithine Decarboxylase / Q000378:metabolism*; D065108:Ornithine Decarboxylase Inhibitors; D010507:Periodicity; D011073:Polyamines / Q000378:metabolism*; D011488:Protein Deficiency / Q000378:metabolism; D051381:Rats
chemical_list: D003959:Diamines; D004044:Dietary Proteins; D065108:Ornithine Decarboxylase Inhibitors; D011073:Polyamines; D004247:DNA; D002262:Carboxy-Lyases; D009955:Ornithine Decarboxylase