HISTOCHEMICAL OBSERVATIONS ON ENZYMES IN PREGNANCY-DEPENDENT MAMMARY TUMORS OF GRS/A MICE

Abstract

Groups of pregnancy-dependent mammary tumors in GRS/A females, composed of maximally grown, slightly and fully regressed tumors, were observed by enzyme-histochemical methods, as compared with normal mammary glands of the same hosts. In such dependent tumors, activities of lactate, succinate and glucose-6-phosphate dehydrogenases and of acid and alkaline phosphatases were weaker than those in parenchymal cells of neighbouring functioning normal mammary glands. ACP was prominently detected in the necrotic foci within regressing tumors after parturition, while other enzyme activity disappeared there. Intensive activity of LDH was detected in some of the lining cells of microcysts within regressed tumors, where other enzymes decreased. In pregnancy-independent mammary tumors of this strain, activities of dehydrogenases except for LDH were much less than adjacent resting normal mammary glands, which seemed to demonstrate similar activities to those of dependent tumors. LDH was quite variable in independent tumors, but its activity became stronger in cancer cells. ALP distributed irregularly in some independent tumors.