Toxicity of 1,1'-alkyl-4,4'-bipyridylium salts in the rat.

Methyl (paraquat), propyl, isopropyl, butyl, methyl-pentyl, hexyl, octyl and benzyl viologens (1,1'-Alkyl-4,4'-bipyridylium salts) were administered subcutaneously to female Sprague-Dawley rats to determine relative toxicities. These compounds all produce the spectrum of effects previously reported for paraquat and additionally produce a focal necrosis at the injection site, nonemptying of the stomach and adrenal enlargement. A lethal dose of propyl, hexyl or benzyl viologen often produced a yellow to red serous fluid in the pleural cavity. Many of the signs observed with viologen poisoning are similar to adrenal hormone effects and the suggestion is made that the adrenals may be contributing to toxicity.