Time point | % ER-α positivea | % PR positivea |
Virgin control | 30.7 ± 1.35 | 31.6 ± 3.1 |
Group 1 | 26.5 ± 5.3 | 38.6 ± 8.5 |
Group 2 | 27.9 ± 7.5 | 28.4 ± 6.6 |
Group 3 | 29.3 ± 8.9 | 29.9 ± 3.0 |
Group 4 | 27.2 ± 3.6 | 14.6 ± 6.5* |
- One thousand cells were counted in mammary gland sections stained for 5BrdU and ER-α or 5BrdU and PR. ([3H]-thymidine and steroid receptors were counted for Group 4.) Group 1 tissue was collected at day 3 of pregnancy, Group 2 tissue was collected at day 4 of pregnancy, Group 3 tissue was collected at day 6 of pregnancy, and Group 4 tissue was collected at day 13 pregnancy after a second 5BrdU dose at day 4. Values are expressed as mean ± standard deviation. aDouble positive for 5BrdU and receptor/total 5BrdU positive. *P < 0.05 versus all groups individually. 5BrdU, 5-bromodeoxyuridine; ER, estrogen receptor; LREC, label-retaining epithelial cell; PR, progesterone receptor.
