Dietary fatty acids are considered promoters of murine and human mammary tumors. The mechanism responsible is not known. Mammary adenocarcinomas in mice originate from preneoplastic cells (hyperplastic alveolar nodules (HAN)) which are derived from normal mammary epithelial cells. Diets rich in linoleic acid (18:2) have been associated with increased incidence of HAN and promotion of tumor growth. Diets rich in stearic acid (18:0) have been associated with decreased incidence of HAN and increased latency period for mammary tumor formation in mice.The effects of dietary 18:0 and 18:2 stages of murine mammary tumorigenesis were examined. The purpose of this study was to determine the effects of these dietary fatty acids on HAN production, mammary gland development, and fatty acid composition of mammary epithelial cells and adipocytes.Spontaneous mammary tumor producing strain A/ST mice were fed a high fat (15%) or low fat (5%) diet. High fat stock (ST) diet containing 1.5% 18:2 or a low fat corn oil (CO) diet containing 3% 18:2 were fed. Animals were sacrificed at 6 or 10 months of age. HAN, ductile and alveolar development were histologically determined in the left inguinal mammary gland. The contralateral gland was on the early diets rich in 18:2 (SF) or 18:0 (SA) were fed. A low*fat enzymatically dissociated and fatty acid compositions of adipocyte and epithelial cells were determined by GLC. Fatty acid profiles were examined for correlation to histologic findings.SA-fed mice had fewer HAN and less well developed mammary alveoli than the other dietary groups which exhibited moderate (ST) or high (CO, SF) HAN incidence. SF-fed mice had the earliest onset of any dietary group. CO-fed mice had later onset of HAN as compared to SF-fed mice but the HAN incidence was similarly high in both groups at 10 months of age.SA-fed mice were protected from development of expected numbers of HAN as compared to ST-fed mice. The reduction in HAN risk in this group was associated with reduced mammary alveolar development. Groups with high risk of HAN (SF and CO) exhibited increased amounts of 18:2 in their mammary epithelial cells and adipocytes. / Department of Biology
| Identifer | oai:union.ndltd.org:BSU/oai:cardinalscholar.bsu.edu:handle/177642 |
| Date | January 1988 |
| Creators | Lee, Michael I. |
| Contributors | Bennett, Alice S. |
| Source Sets | Ball State University |
| Detected Language | English |
| Format | viii, 95 leaves : ill. (some col.) ; 28 cm. |
| Source | Virtual Press |
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