Enzymes of carbohydrate metabolism in human breast carcinoma: relationship with serum hormones.

The enzymes involved in carbohydrate metabolism and their relationship with circulating estradiol (ET2) and prolactin (Prl) were studied in premenopausal and postmenopausal women with fibroadenoma and carcinoma of breast. The activities of all the glycolytic enzymes studied were increased in breast carcinoma tissues except for glyceraldehyde-3-phosphate dehydrogenase which showed decreased activity. Among the glycolytic enzymes studied, hexokinase, phosphofructokinase and glucose-6-phosphate dehydrogenase were found to be stimulated by elevated levels of serum ET2 and further stimulated by a simultaneous increase in Prl. However, the activity of lactate dehydrogenase was more specifically stimulated by Prl rather than ET2. None of the glycolytic enzymes studied was altered in fibroadenoma breast tissues.