Proliferation and apoptosis in the rat endometrium during the estrous cycle as demonstrated by TUNEL and IHC. Rats were killed at different days of estrous cycle (diestrus, proestrus, estrus and metestrus). Uteri were collected, fixed and sectioned for detection of apoptotic cells by TUNEL and IHC of CDC47/MCM7 and cleaved caspase-3. IHC and TUNEL shown are from one representative experiment and were repeated 6 times using 6 different uterine sections from 6 different rats per day of estrous cycle. Arrows indicate example of apoptotic cells. L = lumen, LE = luminal epithelium, S = stroma.