Serum levels of E2 and P4 and E2/P4ratio of serum levels in nonpregnant rats at different stages of the estrous cycle, in nonpregnant rats treated with E2 (20, 200, or 3000 μg/kg 24 h before the experiment), and in pregnant rats at day 3 and day 21 of pregnancy
| Animals | n | n′ | Serum Estradiol | Serum Progesterone | E2 (pg/ml)/P4(ng/ml) Ratio |
|---|---|---|---|---|---|
| pg/ml | ng/ml | ||||
| Nonpregnant | |||||
| Proestrus | 6 | 3 | 58.6 ± 16.9 | 27.9 ± 6.6 | 2.10 |
| Estrus | 6 | 3 | 18.5 ± 6.5 | 30.3 ± 5.7 | 0.61 |
| Metestrus | 6 | 3 | 8.4 ± 3.3 | 38.4 ± 7.9 | 0.22 |
| Diestrus | 6 | 3 | 26.9 ± 9.2 | 32.9 ± 2.5 | 0.82 |
| E2-treated | |||||
| 20 μg/kg | 8 | 4 | 19.8 ± 1.9 | 26.8 ± 8.1 | 0.73 |
| 200 μg/kg | 8 | 4 | 33.1 ± 8.4 | 29.0 ± 5.1 | 1.10 |
| 3000 μg/kg | 8 | 4 | 182.5 ± 28.3 | 21.7 ± 6.7 | 8.41 |
| Pregnant | |||||
| Day 3 | 6 | 3 | 16.7 ± 1.8 | 44.6 ± 4.0 | 0.37 |
| Day 21 | 7 | 3 | 86.4 ± 4.0 | 33.7 ± 5.2 | 2.56 |
Values are means ± S.E.M.
n, number of experiments; n′, number of animals.