EFFECT OF DACTINOMYCIN AND ETHIONINE ON THIOUREA AND PHENYLTHIOUREA TOLERANCE

Death caused by thiourea compounds has been attributed to pulmonary edema. It was found in the present study that thiourea, besides producing pulmonary edema, also caused a severe hypotension. A pretreatment with the sublethal doses of thiourea and phenylthiourea conferred 80% protection to the toxic effects of their respective challenging doses. This protection in both cases was abolished by treating the rats with dactinomycin (actinomycin D) or ethionine one half hour prior to the administration of their sublethal doses. The animals tolerant to the toxic dose of thiourea acquired tolerance to its hypotensive as well as to its edemegenic effects. Treatment of rats with dactinomycin prior to a sublethal dose of thiourea abolished its tolerance conferring ability to toxic doses.; The administration of ethionine did not affect the protective ability of the sublethal dose of phenylthiourea when methionine was given simultaneously, on the other hand, dactinomycin under the same condition abolished the tolerance development. Pretreatment with dactinomycin followed by a sublethal dose of thiourea always resulted in profuse pleural effusion. © 1969 Taylor & Francis Group, LLC.