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. Author manuscript; available in PMC: 2009 Oct 1.
Published in final edited form as: Toxicol Appl Pharmacol. 2008 Jul 1;232(1):78–85. doi: 10.1016/j.taap.2008.06.007

Figure 1. Comparison of control and E2-treated mammary gland after 15 days.

Figure 1

Figure 1

Female ACI rats were treated with an E2 pellet (s.c., 3 mg E2 + 17 mg cholesterol) for 15 days. Control rats were implanted with a pellet containing 17 mg cholesterol only. Histopathologic analyses were performed on mammary tissue from at least 4 control and 4 E2-treated animals. This figure shows mammary tissue representative of the morphology generally observed in control and E2-treated animals. a) The mammary gland of a control ACI rat shows normal tubulolobular architecture (L), consisting of branched ducts (D) terminating in alveolar buds. The branched tubuloalveolar units are more or less evenly distributed in the abundant fat pad (A) of the mammary gland. b) The mammary glands of a rat treated with E2 for 15 days showed proliferative changes characterized by a progressive time-dependent elongation of ducts (D) as well as proliferation and expansion of the terminal lobular units (HLU) with compression of the surrounding fat pad (A).