Figure 4.

Epithelial content of the mammary glands from FVB/N, whey acidic protein-Cre⁺/Cripto^flox (WAP-CRKO), and MMTV-Cre⁺/Cripto^flox (MMTV-CRKO) mice. The quantification of epithelial content of mammary glands was conducted on the whole mounts as described in Materials and Methods. Mice were euthanized at the indicated developmental stage [10-week-old nulliparous females (10 wk), 6 days pregnancy (Early preg.), 15 days pregnancy (Late preg.), one day lactation (1D lac.), and 3 days involution (Early Inv.)], and the fourth inguinal mammary glands were collected and fixed as described in Materials and Methods. FVB/N mice have the highest epithelial content, followed by the WAP-CRKO and MMTV-CRKO mice. In the involuting mammary glands, CRKO experimental mice have significantly higher epithelial content than the involuting mammary glands from FVB/N. A total of at least five to six mice were used for each experiment. ^∗P < 0.05.