PREPARATION OF TISSUES FOR LOCALIZATION OF SEX HORMONES BY AUTORADIOGRAPHY .I. LOSS OF RADIOACTIVE MATERIAL EFFECTED BY USE OF SOME CONVENTIONAL METHODS

Tissues of rats given 3H-oestradiol were prepared for autoradiography according to methods commonly used in light and electron microscopy. By formalin fixation large amounts of radioactive material were lost, both in the fixative and during dehydration. Altogether 78.6±7.5 per cent was extracted from uterine tissue, while 49.0±4.6 per cent was lost from liver tissue removed 15 minutes after the injection. Significantly more radioactivity was lost in the fixative from liver tissue than from uterine. In the former fixation accounted for about 60 per cent of the loss, whereas in the latter it was responsible for about 25 per cent. Osmium tetroxide fixation was found to retain the radioactivity of liver and uterine tissue almost completely. However, large amounts were invariably extracted during dehydration. Although only 3.9±1.2 per cent of the radioactivity of uterine tissue diffused into the fixative, 72.8±12.4 per cent was extracted during ethanol dehydration. A heavy loss was also registered when dehydration and infiltration were carried out in glycol methacrylate. Glutaraldehyde perfusion and postfixation with osmium tetroxide retained almost completely the radioactivity of uterine and pituitary tissue. Nevertheless, nearly all of it was extracted during ethanol/propylene oxide dehydration and Epon embedding. The methods studied are not adequate for accurate autoradiographic localization of oestradiol. © 1969 Springer-Verlag.