THE ACTION AND TOXICITY OF RETRORSINE

¹ From the Lilly Research Laboratories, Indianapolis

Retrorsine, an alkaloid of Senecio retrorsus, in the form of a hydrochloride induces weakness and paralysis of the extremities of frogs in the dosage of 1 mgm. per gram.

In white mice it causes acute death within two and one-half hours, with clonic convulsions, in the dosage of 290 or more mgm. per kilogram, injected intravenously. Doses of 70 to 145 mgm. per kilogram produce no convulsions but hepatic necrosis and renal degeneration in the majority of animals, and finally death in one to eight days.

In guinea pigs, the minimal lethal dose of retrorsine hydrochloride by intravenous injection is approximately 320 mgm. per kilogram. An amount equivalent to 50 per cent of the minimal lethal dose, repeated every other day for four doses, failed to bring about any visceral changes in ten days. The guinea pig is apparently less susceptible than the mouse to this alkaloid.

Retrorsine has a depressor and a hyperglycemic action. It inhibits isolated rabbits' intestines, but contracts isolated guinea pigs' virgin uteri.