Further studies on the effects of blocking agents on protein synthesis in goldfish brain

Abstract— In further experiments on the effects of antibiotic agents on protein synthesis in the goldfish brain, doses of intracranially-injected puromycin or acetoxycycloheximide higher than those previously employed did not hasten the onset of inhibition of incorporation of intraperitoneally-injected ³H]leucine into brain protein. The antibiotic-resistant incorporation was not due to the presence of labelled blood protein in the brain. After the intracranial injection of labelled puromycin, the appearance of radioactivity in the acid-soluble fraction of brain was blocked by acetoxycycloheximide. Repeated daily intracranial or intraperitoneal injections of puromycin were lethal, and acetoxycycloheximide was not protective, indicating that peptidyl-puromycin was present in the brain but did not account for the lethality of puromycin. Behavioural experiments argued against but did not totally exclude the possibility that peptidyl-puromycin was responsible for the amnestic effect of puromycin. Puromycin aminonucleoside, O-methyl tyrosine and 5-guanylyl methylenediphosphonate had little or no effect on protein synthesis in brain, but gougerotin was slightly inhibitory.