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. Author manuscript; available in PMC: 2014 May 1.
Published in final edited form as: Breast Cancer Manag. 2013 Jul 1;2(4):283–294. doi: 10.2217/bmt.13.16

Figure 1. Experimental design.

Figure 1

Fifty-day-old virgin female Sprague–Dawley rats were divided into four groups (20 animals each). The control group received ip. bacteriostatic water (hCG vehicle) daily for 21 days. The hCG group received 100 IU/day of r-hCG (Ovidrel®). The pellet group received a surgically implanted pellet containing estrogen and progesterone at 0.72 mg 17-β estradiol and 200 mg progesterone with a 21-day release period. The pregnancy group rats were mated, allowed to complete pregnancy (21 ± 2 days) and, after delivery, were separated from the offspring. Each group was exposed to pregnancy or hormone treatment for 21 consecutive days and, at the end of the exposure, they had a resting period of 21 days to allow the involution of the mammary gland. At the end of the resting period, the animals were euthanized and their abdominal mammary glands were collected. Ten animals per group had their mammary glands collected for histological analysis, and the other ten animals had their mammary glands collected for genomic analysis.

hCG: Human chorionic gonadotropin; ip.: Intraperitoneally; r-hCG: Recombinant human chorionic gonadotropin.

Adapted with permission from Springer Science+Business Media BV [36].