INHIBITORY EFFECT OF AUREOMYCIN (CHLORTETRACYCLINE) PRETREATMENT ON SOME RAT LIVER MICROSOMAL ENZYME ACTIVITIES

Rats were subjected to intraperitoneal injections of varying amounts of chlortetracycline to study the effects of this antibiotic on rat liver microsomal drug metabolism. The chlortetracycline-treated rats were then compared with sham-injected controls and phenobarbital-treated animals. Compared with the control animals, the chlortetracycline-treated animals gained weight more slowly, their livers were smaller, the microsomal protein per unit weight of liver was less, the hepatic microsomal cytochrome P-450 content and metabolism in vitro of aminopyrine and hexobarbital were decreased while the hexobarbital sleeping time was markedly increased. The phenobarbital-treated animals showed the usual increase in all of the hepatic microsomal components and a marked decrease in hexobarbital sleeping time. Our data would indicate a possible inhibition of microsomal protein synthesis by chlortetracycline treatment, supporting the suggested mechanism of action of the tetracycline antibiotics. © 1969.