To develop the potential function of dairy cow mammary stem cells (DCMECs) in regu‐lation of lactation ,we identify putative DCMECs which were BrdU label retaining epithelial cells , at the same time ,analysis the location of two new mammary stem cells molecular marks FNDC 3B and PROCR to verify the feasibility of them to indicate DCMECs .The mRNA levels of prolactin , growth hormone ,insulin‐like growth factor‐1 and their receptors were detected along with cell passage by Real‐time quantitative PCR .The results showed that the proportion of BrdU label‐re‐taining epithelial cells was nearly 0 .4% after 25 d continuous culture (passaged 4 times) and few cells were positive for FNDC3B or PROCR .Moreover ,we observed the BrdU labelled epithelial cells by asymmetric division .The mRNA levels of prolactin ,growth hormone ,insulin‐like growth factor‐Ⅰ and their receptors in primary and passage cells were extremely significant difference (P<0.01) .DCMECs would rapidly lose some physiological characteristics and the ability of milk synthesis w hen not under the condition of induction of lactation differentiation ,but a certain per‐centage of mammary stem/progenitor cells will be retained ,w hose potential effects on the regula‐tion of lactation and mammary acinar remodeling were worthy of attention .%为了揭示奶牛乳腺干细胞在体外泌乳调控中的潜在作用，本研究根据成体干细胞具有BrdU标记滞留的特点检测了奶牛乳腺上皮细胞（DCMECs）中疑似乳腺干／祖细胞，同时分析了两种新发现的乳腺干细胞分子标志（FNDC3B和PROCR）的表达定位，验证了它们指示DCMECs的可行性。通过实时荧光定量 PCR方法检测分析DCM ECs体外培养过程中催乳素、生长激素、胰岛素样生长因子Ⅰ及其受体的基因表达变化。结果显示，连续培养25 d后BrdU标记滞留细胞比例接近0.4％，极少数细胞呈FNDC3B或 PROCR阳性，可以观察到不对称分裂细胞，原代和传代后DCMECs在激素、胰岛素样生长因子及其受体mRNA水平上差异极显著（P＜0.01）。总之，在非诱导泌乳分化培养条件下，脱离泌乳生理环境的DCM ECs自身具有的泌乳调控基因表达迅速受到抑制，但在一定培养时间内，DCM ECs群体中能够保留一定比例疑似乳腺干／祖细胞，提示这些多能奶牛乳腺干／祖细胞在体外泌乳调控和乳腺腺泡重塑过程中可能发挥重要作用。
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