RELATIONSHIP BETWEEN PITUITARY-HORMONES, ANTIOXIDANT ENZYMES, AND HISTOPATHOLOGICAL CHANGES IN THE MAMMARY-GLAND OF SENESCENT RATS

In order to assess the possible involvement of endocrine factors and a ntioxidant enzymes (AGE) in the mammary pathology typically observed i n old female rats, we undertook to determine the relationship between pituitary hormones, AOE activity, and histopathological changes in the mammary gland of senescent rats carrying neoplastic and nonneoplastic mammary pathologies. Serum levels of several pituitary hormones were determined by RTA in young (five months) and senescent (33 months) Spr ague-Dawley female rats. The activity of catalase (CAT) and superoxide dismutase (SOD) in mammary tissue from the senescent animals was also determined. Senescent rats showed higher levels of prolactin (PRL) (p < 0.01), thyroid-stimulating hormone (TSH) (p < 0.05) and follicle-st imulating hormone (FSH) (p < 0.01) than their young counterparts. In s enescent females the main histopathological findings at mammary level were a marked hyperplasia and the presence of fibroadenomas. In this g roup there was a positive correlation between serum levels of PRL and the activity of mammary SOD (p < 0.05). There was also a positive corr elation between serum levels of FSH and the activity of mammary CAT (p < 0.001). Young females, rendered moderately hyperprolactinemic by me ans of anterior pituitary grafts, showed clear proliferative changes i n their mammary glands. Senescent rats carrying fibroadenomas were les s hyperprolactinemic than those with mammary hyperplasia (p < 0.05). O ur results provide additional support to the idea that PRL may be a ph ysiological modulator of mammary SOD activity and suggest that FSH can possibly influence the activity of CAT in mammary gland. They also su ggest that tumorigenesis but not hyperplasia in rat mammary gland may be associated with low mammary SOD and CAT activities. (C) 1997 Elsevi er Science Inc.