Fig. 1.
Intensity of progesterone receptor immunostaining in mammary epithelium is decreased despite higher 17β-estradiol serum levels in ERΔ3 mice. a Progesterone receptor immunostaining intensity in mammary epithelial cells are shown for wild-type (WT) FVB/N (n = 6) and lines D (n = 6) and F (n = 8) ERΔ3 female mice. Two-way ANOVA showed no significance for genotype, but significance was observed for the level of staining and the interaction of staining and genotype (p < 0.01). Bonferroni tests identified significance between the groups as shown in the graph: a relative to cells without staining (none); b relative to weakly staining cells (weak); c relative to moderately staining cells (mid); and asterisk designates significance compared to the strongly staining cells (strong) in WT mice, p < 0.05. p <0.001 for WT and line F for none vs. strong as well as weak vs. strong and mid vs. strong for WT; p <0.01 for weak vs. strong for line F; and p <0.05 for none vs. mid for WT and mid vs. strong for line D. b Serum 17β-estradiol (E 2) levels for WT (n = 13) and line F (ERΔ3, n = 16) 3-month-old female mice in estrus were significantly different (p = 0.009, Mann–Whitney test). c Progesterone (P 4) serum levels were not significantly different for WT (n = 13) and line F ERΔ3 mice (n = 16) in estrus at age 3 months