TABLE 2

Model parameters for plasma 17β-estradiol (E2) and estrogen receptor (ER) dynamics

ParameterDefinitionEstimate (% CV) or Value (Source)
Plasma estradiol concentrations
 BL (pg/ml)Baseline concentrations of E26.85 (5.8)
 A (pg/ml)Peak amplitude in met/diestrus8.6 (14.8)
 B (pg/ml)Peak amplitude in proestrus32.3 (10.5)
 Tpk1 (h)Time of peak amplitude in met/diestrus52.3 (3.5)
 Tpk2 (h)Time of peak amplitude in proestrus82.2 (0.8)
 αFitting coefficient for first peak191 (37.5)
 βFitting coefficient for second peak106 (16.7)
 τ (h)Duration of estrous cycle96 (fixed)
ER binding and dynamics
 fup,E2Unbound fraction of estradiol in plasma0.053 (Plowchalk and Teeguarden, 2002)
 Bmax,ER (liver) (fmol/mg of protein)ER content in liver24.5 (Aten et al., 1978; Dickson and Eisenfeld, 1979)
 Bmax,ER (uterus) (fmol/mg of protein)ER content in uterus560 (Notides, 1970)
 KD,ER(liv) (pM)ER binding constant in liver140 (Dickson and Eisenfeld, 1979)
 KD,ER(uterus) (pM)ER binding constant in uterus100 (Branham et al., 2002)
 kt (h−1)Translocation rate constant58.3 (Assumed equal to GR)