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Relationships Between the Influence of Cortisol on Tissue Amino Acid Accumulation and Amino Acid Incorporation Into Protein, and the Cortisol Inhibition of Substrate Metabolism 1

1970; Oxford University Press; Volume: 86; Issue: 5 Linguagem: Inglês

10.1210/endo-86-5-996

1945-7170

Y Ariyoshi, John E. Plager,

Coenzyme Q10 studies and effects

The in vitro effect of cortisol on the cellular accumulation of free amino acid or a-aminoisobutyric acid and the incorporation of amino acid into protein was studied using the mouse ear strip preparation. It was determined that cortisol strongly inhibited amino acid incorporation into protein in glucose medium, weakly inhibited this incorporation in pyruvate medium and did not inhibit it at all in succinate medium. The cortisol inhibition of the metabolism of these substrates to CO2 followed the same sequence, i.e., glucose, pyruvate and no inhibition of succinate. Cortisol usually shows at least a 3-hr latent period in glucose medium before an inhibition of amino acid incorporation into protein can be demonstrated. This latent period is decreased to less than 30 min by preincubation of the tissue with cortisol in succinate medium. These data are interpreted to mean that this cortisol action on protein synthesis is manifest through inhibition of specific substrate metabolism and subsequent energy generation, but that the primary action of cortisol is not on this system. Cortisol will inhibit the accumulation of free amino acid or aminoisobutyrate in the tissue and this effect is independent of the substrate used for incubation; therefore, inhibition of amino acid accumulation in the cell is not dependent on cortisol inhibition of substrate metabolism. Cortisol appears to inhibit amino acid incorporation into protein independently of its inhibition of amino acid accumulation, and these 2 actions need not be related. (Endocrinology86: 996, 1970)