Editor’s Statement This study combines cultured cells and direct analytical approaches to show that authentic transferrin is a major mouse milk protein and is regulated differently than beta-casein in mammary epithelium. Wallace L. McKeehan
Summary
We have identified a major mouse milk protein as transferrin (Tf) using immunoprecipitation, 2-dimensional electrophoresis, Ouchterlony diffusion and V-8 protease digests. We show that Tf is synthesized by mammary epithelial cells themselves and that its synthesis and secretion is regulated distinctly from that of other milk proteins. In culture, the kinetics of Tf synthesis and secretion are distinct from that of β-casein; furthermore, Tf is relatively insensitive to lactogenic hormones whereas β-casein is hormone-dependent.In vivo, however, Tf is regulated by pregnancy. While the virgin gland produces small amounts of Tf, its production is greatly increased during pregnancy and lactation. Thus, Tf synthesis in the mammary gland is modulated by as yet unknown factorsin vivo. These observations are discussed in terms of Tf’s possible role in mammary gland growth, differentiation and function.
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This research was supported by the OHER office of U. S. DOE, contract DE-AC 03-76S F00098, and NIH grant BRSG RR05918.
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Lee, E.Y.H., Barcellos-Hoff, M.H., Chen, L.H. et al. Transferrin is a major mouse milk protein and is synthesized by mammary epithelial cells. In Vitro Cell Dev Biol 23, 221–226 (1987). https://doi.org/10.1007/BF02623583
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DOI: https://doi.org/10.1007/BF02623583