Fixation of catecholamine-containing tissues for histochemical demonstration of catecholamines and for radioautography of steroid hormones in the same sections

A new combination of freeze-drying, formaldehyde induced fluorescence method for catecholamines and autoradiography of water soluble substances was developed and tested with different tissues containing biogenic amines. The freeze-dried tissue pieces were fixed with vaporours paraformaldehyde and OsO₄ before embedding procedure. The effect of OsO₄-vapour on the formaldehyde induced fluorescence was tested. The method produces semi-thin sections in which the fluorescence is well preserved and the tissue lightly stained with OsO₄ which also fixes the steroid hormones used for radioautography.