RT Journal Article SR Electronic T1 Heme Regulation of Cytochrome Oxidase Synthesis in Fetal Rat Liver JF Molecular Pharmacology JO Mol Pharmacol FD American Society for Pharmacology and Experimental Therapeutics SP 50 OP 59 VO 13 IS 1 A1 JAMES S. WOODS YR 1977 UL http://molpharm.aspetjournals.org/content/13/1/50.abstract AB The role of heme in regulation of the synthesis of cytochrome oxidase, a mitochondrial hemoprotein, was studied in fetal rat liver. A functional association between heme levels and the synthesis of cytochrome oxidase in vivo is suggested by the rapid decline in the rate of incorporation of [3H]δ-aminolevulinic acid and, subsequently, [14C]leucine into cytochrome oxidase following selective inhibition of heme biosynthesis with CoCl2. Both the functional activity and the rate of [14C]leucine incorporation into fetal cytochrome oxidase are stimulated when heme is administered 30 min after CoCl2 is given. In contrast, heme does not stimulate [14C]leucine incorporation or enhance the functional activity of cytochrome oxidase following selective inhibition of cytoribosomal protein synthesis with cycloheximide. Thus it is suggested that heme stimulates the synthesis of apocytochrome oxidase de novo and mediates the formation of the functional cytochrome in fetal rat liver. ACKNOWLEDGMENTS The author acknowledges the excellent technical assistance of Mrs. Geraldine Carver in the performance of these studies.