High affinity oestradiol receptors and the activity of glucose-6-phosphate dehydrogenase and lactose synthetase in mammary carcinomata of postmenopausal women.

The determination of hormone inducible proteins in endocrine tumours may yield information about the presence of hormone dependent tumour cells. We have estimated the high affinity oestradiol binding capacity in primary mammary carcinomata of 57 postmenopausal patients. Glucose-6-phosphate dehydrogenase and lactose synthetase are known from animal experiments to be hormone inducible. Therefore, in biopsies of sufficient size the activity of glucose-6-phosphate dehydrogenase (47 pateints) and lactose synthetase (23 patients) was also studied. It was found that biopsies with high binding capacity also showed high activities of glucose-6-phosphate dehydrogenase and lactose synthetase A protein (galactosyl transferase). No lactose synthetase B protein (alpha-lactalbumin) has been discovered in the tumours. The present observations may be considered suggestive evidence of a relationship between high oestradiol binding capcity and high activities of the two enzymes on the one hand and hormone dependence of the tumour on the other. However, further clinical studies are required before final conclusions in this respect can be drawn.