Trimethyltin ototoxicity in albino rats.

The toxicity of alkyltin compounds is of exceptional interest due to the dissimilar toxic effects of some very closely related structural analogues among this class of compounds. Since several features of the toxicity of trimethyltin appeared to be consistent with a mechanism involving accumulation of the toxicant on melanin pigments, the ototoxicity induced by TMT exposure was examined in albino rats. Hearing thresholds for tones sampling the mid- and high-frequency range of the rat's audibility function were assessed by reflex inhibition audiometry. TMT produced a frequency dependent loss of auditory sensitivity that was most severe in the high frequency range. The TMT-induced impairment of auditory function was similar to that previously observed in pigmented Long-Evans rats. These results extend the observation of TMT-induced hearing loss to a non-pigmented rodent strain and suggest that the accumulation of TMT on cochlear melanin is not critical to the production of hearing impairment by TMT.