Tetracycline and Incorporation of Amino Acids into Proteins Of Rat Tissues. ∗

Summary

Tetracycline decreased incorporation of labeled amino acids into the proteins of a number of organs when given intragastrically, intramuscularly or intravenously into intact rats. The effects are dose related and are not uniform for every tissue. Gastrointestinal tract, pancreas and skeletal muscle were more affected than were organs such as liver and kidney. The antibiotic effect appears to be independent of food intake, local trauma, or stress factors mediated through the adrenal gland. Turpentine injection resulted in changes similar to those with tetracycline and it is suggested that these may be caused by systemic effects of the former. A non-specific effect of tetracycline, turpentine and mechanical trauma was manifest by a rise in amino acid incorporation into the plasma proteins of female rats. The data support the hypothesis that tetracycline is capable of inhibiting protein synthesis in intact mammals at plasma levels which have been noted to cause significant metabolic changes in man.