The histochemistry of oestradiol-17β and isocitric dehydrogenases in endometrial carcinoma

Abstract Specimens of endometrial carcinoma were obtained from 8 women, four of whom had previously been treated with oral medroxyprogesterone acetate 200 mg daily for 7 days. The activities of oestradiol-17β and isocitric dehydrogenases and nuclear oestradiol receptor concentrations were measured in the homogenised tissue and both enzymes were located histochemically. Histochemical evidence of oestradiol dehydrogenase activity was found in all but one of the specimens with biochemical activity. This anomalous specimen was obtained from a woman who had not been treated with MPA and whose endometrium exhibited only low levels of enzyme activity. The histochemical staining caused by isocitric dehydrogenase was intense but bore no relation to the biochemical measurement of enzyme activity in the homogenate. The modified technique for the histochemical demonstration of oestradiol dehydrogenase activity although not quantitative gave results similar to the biochemical methodology. It may therefore be useful as a simple test of the prediction of the sensitivity of endometrial carcinoma to progestogens.