Quantitative assessment of the polysome profile of the livers of mice treated with tetracycline or doxycycline.

The influence of tetracycline and doxycycline (10-100 micrograms/g i.v.) on the aggregational state of ribosomes from mouse liver was tested. Both drugs caused a disaggregation of the ribosomes as evidenced by a rise of the monosomes + disomes/polysomes ratio. Tetracycline was much more potent than doxycycline, the minimum effective doses for tetracycline being 10 micrograms/g i.v. as compared to 100 micrograms/g for doxycycline. The results show that tetracycline but not doxycycline at therapeutic dose range may interfere with the protein synthesis of the liver.