Protein Synthesis in Rat Liver: Influence of Amino Acids in Diet on Microsomes and Polysomes

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Science  29 Oct 1965:
Vol. 150, Issue 3696, pp. 628-629
DOI: 10.1126/science.150.3696.628


Rats were killed 1 hour after having been fed by stomach tube with amino acid mixtures that were either nutritionally complete or lacked tryptophan. Microsomes isolated from the livers of animals fed the incomplete mixture showed a reduced capacity to incorporate 14C-leucine in vitro, and polysomes prepared from the same livers showed an increased proportion of monosomes and disomes. Prior treatment with actinomycin D did not prevent these differences in response to the two amino acid mixtures, an indication that synthesis of messenger RNA may not be involved in the cell mechanism which recognizes differences in amino acid pattern.