Effect of endocrine organ ablation on the uptake and clearance of 9, 10-dimethyl-1,2-benzanthracene-9-14C by mammary parenchymal cells of the rat.

from the right side of the rat were used to determine the radioactivity contained within the mammary teat, fat pad, and vascular areas, while those from the left side were separated into parenchymal cell and fat cell fractions. The intracellular lipid of the parenchymal cells was extracted and quantitated. Although the pattern of carcinogen uptake and clearance by the parenchymal cell intracellular lipid was similar in all 3 groups, a greater concentration of DMBA was found in the fraction obtained from ovariectomized and hypophysectomized rats sacrificed at the later time periods. These data indicated that the intracellular lipid of the parenchymal cell is important in the uptake of carcinogen by ovariectomized and hypophysectomized rats, as well as in intact rats. Furthermore, endocrine alteration of parenchymal cell uptake of carcinogen may have resulted from changes in the amount of parenchymal cell intracellular lipid and not in changes in the amount of lipid in the mammary gland fat pad. The specific activity of the dry, fat-free parenchymal cell residue of intact rats was maintained at higher levels than the residue of either ovariectomized or hypophysectomized rats. It appeared that the DMBA was bound to some cellular component(s) of mammary parenchyma in all 3 groups of animals. However, the degree of carcinogen binding and the maintenance of bound carcinogen within the parenchymal cells of ovariectomized and hypophysectomized rats appeared to be altered. Although this investigation does not explain the modification of DMBA-induced mammary carcinogenesis resulting from ovariectomy and hypophysectomy, it does suggest that it may be the result of alterations in the metabolism and/or binding of carcinogen by the parenchymal cell.