The inhibitory action of L-dihydroxyphenylalanine (L-dopa) in the presence of a monoamine oxidase inhibitor on protein synthesis in vivo and the partial amelioration of this by methionine supplementation.
Male Wistar rats of various age groups were injected daily over a period of 3 weeks with iproniazid (10 micrograms/g body wt.) and L-dihydroxyphenylalanine (L-dopa; 0.1 mg/g body wt.). On the final day 1 h before the termination of the experiment the animals were injected with L-[14C]valine (0.1 microCi/g body wt.). The specific radioactivity of the valine in the proteins of the subcellular fractions of the tissues examined, relative to the time-integrated mean specific radioactivity of this amino acid in the acid-soluble pools of these tissues, was used to assess protein synthesis. The L-dopa/monoamine oxidase-inhibitor treatment was associated with 30--40% inhibition of protein synthesis. Supplementation of the dietary methionine intake by injection of this amino acid markedly diminished the inhibitory action of the L-dopa/monoamine oxidase-inhibitor treatment on protein synthesis in all fractions examined.
D000367:Age Factors; D000818:Animals; D001921:Brain / Q000378:metabolism; D003864:Depression, Chemical; D007490:Iproniazid / Q000494:pharmacology*; D007668:Kidney / Q000378:metabolism; D007700:Kinetics; D007980:Levodopa / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism; D008297:Male; D008715:Methionine / Q000494:pharmacology*; D014176:Protein Biosynthesis; D051381:Rats; D013347:Subcellular Fractions / Q000378:metabolism
D007980:Levodopa; D008715:Methionine; D007490:Iproniazid