TABLE 2.
Model parameters for plasma 17β-estradiol (E2) and estrogen receptor (ER) dynamics
| Parameter | Definition | Estimate (% CV) or Value (Source) |
|---|---|---|
| Plasma estradiol concentrations | ||
| BL (pg/ml) | Baseline concentrations of E2 | 6.85 (5.8) |
| A (pg/ml) | Peak amplitude in met/diestrus | 8.6 (14.8) |
| B (pg/ml) | Peak amplitude in proestrus | 32.3 (10.5) |
| Tpk1 (h) | Time of peak amplitude in met/diestrus | 52.3 (3.5) |
| Tpk2 (h) | Time of peak amplitude in proestrus | 82.2 (0.8) |
| α | Fitting coefficient for first peak | 191 (37.5) |
| β | Fitting coefficient for second peak | 106 (16.7) |
| τ (h) | Duration of estrous cycle | 96 (fixed) |
| ER binding and dynamics | ||
| fup,E2 | Unbound fraction of estradiol in plasma | 0.053 (Plowchalk and Teeguarden, 2002) |
| Bmax,ER (liver) (fmol/mg of protein) | ER content in liver | 24.5 (Aten et al., 1978; Dickson and Eisenfeld, 1979) |
| Bmax,ER (uterus) (fmol/mg of protein) | ER content in uterus | 560 (Notides, 1970) |
| KD,ER(liv) (pM) | ER binding constant in liver | 140 (Dickson and Eisenfeld, 1979) |
| KD,ER(uterus) (pM) | ER binding constant in uterus | 100 (Branham et al., 2002) |
| kt (h−1) | Translocation rate constant | 58.3 (Assumed equal to GR) |