Polyamine metabolism will be examined in the mammary glands of rats undergoing DMBA-induced mammary carcinogenesis, and in the mammary tumors subsequently formed. In addition to changes in polyamine metabolism due to carcinogen, changes due to hormonal manipulations will also be investigated. We shall study the levels of spermidine, spermine, putrescine, and their monacetyl derivatives in the mammary glands and mammary tumors. We shall also investigate the effect of DMBA treatment and hormonal manipulations on the levels of the enzymes of polyamine metabolism, ornithine decarboxylase, S-adenosylmethione decarboxylase, spermidine synthease, spermine synthase, and spermidine acetyl transferase, in the mammary gland and in mammary tumors.