Bile Ducts - pathology, Liver - pathology, Apoptosis - drug effects, Bile Ducts - chemistry, Mitogen-Activated Protein Kinase 3 - analysis, Proliferating Cell Nuclear Antigen - analysis, Estrogens - administration & dosage, Bile Duct Diseases - pathology, Bile Duct Diseases - prevention & control, Mitogen-Activated Protein Kinase 1 - analysis, Estradiol - ad...