Preferential Accumulation of Iron in Hyperplastic Tissue of Rat Mammary Gland

Abstract

Quantitative measurements of the iron contents of various rat mammary tissues (normal, hyperplastic, and tumor) revealed that hyperplastic tissues contained significantly more iron than normal and tumor tissues. Normal mammary glands from virgin, pregnant, lactating, and retired breeder rats had an iron content ranging from 21 to 73 μg/100 mg dry weight (X = 43), while that of primary and transplantable DMBA-induced mammary tumors ranged from 31 to 52 μg/100 mg dry weight (X = 38). In contrast, the iron content of hyperplastic mammary tissue, both DMBA-induced and spontaneous, was 139 to 204 μg/100 mg dry weight (X = 176). Thus, in addition to their previously reported growth alterations, rat mammary hyperplasias are also physiologically altered from normal in their sequestering of iron. Although the mechanisms involved are unknown, this property should provide a useful quantitative index for in vivo assays of mammary hyperplasias induced in vitro.