Abstract
To elicit the effect of dietary fat structure on mammary tumorigenesis, young female rats were given dimethylbenz(a)anthracene (DMBA) followed by diets containing triacylglycerol (TAG) or diacylglycerol (DAG). Two types of DAG prepared from fatty acids from rapeseed and palm oils in addition to these vegetable oils (TAG as respective control oils) were fed at the dietary level of 7%. DAG, irrespective of the source, showed similar effects on the indices of mammary tumorigenesis including the incidence and cumulative number of tumors, tumor multiplicity, and tumor burden to those for the corresponding TAG during 90 days of the feeding period, although the cumulative number of tumor tended to be lower in both TAG and DAG from palm oil than those from rapeseed oil. DAG in relation to TAG gave same results with respect to food intake and weight gain, but there was a decreasing trend of white adipose tissue weights, in particular the periovarian tissue. The weight of brown adipose tissue remained unchanged. Serum TAG level in rats fed DAG was lower than in those fed TAG. These observations indicate that DAG is at least no more tumorigenic than TAG in DMBA-induced mammary tumor model, but reduces body fat mass.
