Figure 5

Hormone-dependent activation of a subset of eLLRCs in the adult mammary gland. (A) Diagrammatic representation of protocol used to examine proliferation of embryonic LLRCs during hormone treatment in adult virgin mice. Embryonically EdU-labeled adult mice were injected daily for two weeks with estrogen and progesterone (E + P) or vehicle and with BrdU twice/day. (B) FACS profiles of luminal CD24⁺CD49f^low and basal CD24⁺CD49f^high cell populations isolated from either control or E + P treated 10-week old mammary glands. (C , D) Immunofluorescent staining of paraffin sections for EdU and BrdU. Scale bar represent 20 μm. (E) Histograms showing quantification of the eLLRCs that proliferate after hormone treatments. Hormone treatment resulted in a 1.7-fold increase in the number of EdU+ LLRCs labeled with BrdU. Data represent mean ± SEM of n = 3 mice each. BrdU, 5-bromo-2′-deoxyuridine; EdU, 5-ethynl-2′-deoxyuridine; eLLRCs, embryonically derived long label retaining cells; SEM, standard error of the mean.