Figure 6.

Results of immunostaining for PCNA (A,C) and PR (B,D) in mammary gland. (A) Photomicrograph showing PCNA immunostaining in control tissue. (B) Photomicrograph showing PR immunostaining in E₂ high mammary gland. Percentage of PCNA-positive (C) and PR-expressing (D) epithelial cells in mammary terminal structures. Immunostained PCNA cells were regularly seen in all animals (C). PR-expressing cells were seen in both in E₂ groups and in the GEN high group (D); note the reduced number of PR-expressing cells in E₂ high versus E₂ low mammary glands. Bars = 20 μm.

*p < 0.05 compared with control; **p < 0.05 compared with E₂ low.