Arginase and glucose-6-phosphate dehydrogenase activities in spontaneous mammary carcinogenesis

Arginase and glucose-6-phosphate dehydrogenase activities in the mammary glands of 4, 8 and 12 month old groups and in precancerous nodules and mammary tumours in (C3H Jax) virgin mice were studied. It was observed that activities of both the enzymes in different age groups of both the strains are comparable, but are significantly lower than those present in precancerous nodules and mammary tumour. Activities of both the enzymes in the precancerous nodules and tumour tissue are comparable.

Differential response of ribonucleic acid polymerase in preneoplastic and neoplastic ovaries of mice following oestradiol treatment

The activity of RNA polymerase has been determined in the nuclear fraction of normal mouse ovaries, 60-day-old preneoplastic intrasplenic ovarian grafts, and ovarian tumours developed after 7 months of ovary grafting into the spleen. In preneoplastic grafts, RNA polymerase activity corresponds to that of normal ovaries, while in ovarian tumours, the enzyme value was 2-3 times higher. Oestradiol injected for 10 days, acting as depressant of the host pituitary gonadotrophic potency, decreased the enzyme level in the grafts, whereas no change was observed in similarly treated tumours. These facts indicate that hormonal mechanisms regulating the genetic nuclear expression are operating only in the 2-month-old preneoplastic ovarian cell, while autonomy from these regulating mechanisms is achieved by 7-month-old tumour cells.