Figure 1.

Treatment schedule and gross appearance of uteri at the time of sacrifice. Various treatment groups (Gp) were used to study how mouse uterine stem cells are modulated by hormones under varying conditions of endometrium including atrophy, growth and remodeling/regeneration. Mice were bilaterally ovariectomized (on Day 0) and 14 days later were subjected to various hormonal treatments as shown. Gp A received no hormonal treatment, were sacrificed on Day 25 and the uterus appeared atrophied evident by its very thin appearance compared to other groups. Gp B, D & E received estradiol (E, 100 ng/day) priming for six days (D14-19). Gp B was treated with 50 ng/ml estradiol on Day 25 and sacrificed 24 hrs later to study the proliferative effect of estradiol on endometrial cells. Gp C was not primed with estradiol, only received progesterone (P, 1 mg/day) on Days 21-24 and sacrificed 24 hrs later to study the effect of progesterone alone on the endometrium. Gp D received estradiol priming, progesterone on Days 21-24 and also estradiol (50 ng) on Day 24, and was sacrificed 24 hrs after the treatment on Day 25 was the E + P treated receptive phase endometrium with maximal growth. Gp E reflected condition of remodeling/regeneration resulting by withdrawal of hormones. These mice were treated as Gp D and were sacrificed 48 hrs after Gp D i.e. on Day 27.