Localization of oestradiol in the rat nasal mucosa.

The metabolism of 4-14C-oestradiol in the rodent respiratory tract has been investigated in vitro. Using thin-layer radiochromatography, at least 3 and 2 metabolites were found at incubation with slices from the rat olfactory mucosa and lung, respectively. Autoradiography of the nasal region of rats injected intravenously with 4-14C-oestradiol showed a high level of radioactivity in the mucosa covering the respiratory region, and in the subepithelial parts of the olfactory mucosa. Autoradiography of rat and mouse lung slices incubated with 4-14C-oestradiol showed that a selective localization of radioactivity occurred in the bronchial mucosa. The radioactivity in the mucosa of the respiratory tract was reversibly bound and could be extracted with organic solvents.