Normal pregnancy-induced mammary gland development. (A) Histological analysis of hematoxylin-eosin Y-stained mammary glands at several time points: 14, 17, and 18 days postcoitum (dpc), lactating day 0 (L0), and L1. (B) Stat5 (red) and E-cadherin (green) immunostaining of postpartum mammary glands. Stat5 and DAPI signals overlapped, indicating that Stat5 is located in the nucleus (not shown). (C) α-Smooth muscle actin immunostaining. Bsx+/−, Bsx heterozygous mutant female; Bsx−/−, Bsx homozygous mutant female.