PHOSPHORUS METABOLISM IN VIRAL-INDUCED NEOPLASIA: II. IN VIVO AND IN VITRO STUDIES OF THE MILK AND MAMMARY GLAND LIPIDES OF STRAINS OF MICE SUSCEPTIBLE TO THE MAMMARY TUMOR VIRUS

Abstract

Studies of phosphorus metabolism in the mammary glands of C3HZ, C3HZb, and A strain female mice have been carried out using P32-labeled inorganic phosphate. Chemical and radioactivity measurements of labeled phospholipides, nucleic acids, and phosphoproteins of mammary tissue were obtained. The fatty acid composition of the chromatographed and separated phospholipides, neutral fat, and free fatty acids of milk of high-cancer-strain (C3HZ and A) females were compared to patterns obtained for low-cancer-strain (C3HZb) females. The lipide pattern of the mammary tumor virus fraction obtained by ultra-centrifugation was investigated and compared to the results found for mammary gland and milk. The C3HZ female bearing mammary tumors exhibited increased synthesis of phospholipides and nucleic acids when compared to the genetically similar, low-cancer-strain C3HZb females and to identical C3HZ females that had not yet developed mammary tumors. Investigation of the phospholipide fatty acid composition of the milk and mammary glands of high- and low-cancer strains revealed further marked differences with respect to the palmitoleic and linoleic acid content.