Autoradiography in mice of tritiated 2-(2-furyl)benzimidazole and melanin-binding in vitro.

The distribution of tritiated 2-(2-furyl)benzimidazole ([3H]FB) in male and pregnant albino mice and male pigmented mice was studied by whole-body autoradiography. The most notable finding was the accumulation of radioactivity in the melanin-containing tissues of the eye, the inner ear and the hair follicles. An additional study in vitro on isolated bovine-eye melanin showed a substantial binding of [3H]FB to the melanin. The general distribution was characterized by a rapid excretion pattern, except for uptake in the thyroid and nasal mucosa. Transfer to fetuses was significant and the fetal distribution was dominated by excretion.