The time course of plasma levels of (A) COC, (B) BE, and (C) EME for dams sacrificed 1, 2, or 3 h after an injection of cocaine (10 mg/kg, subcutaneously) on different postpartum days from day 4 –24. Each bar represents the mean ± S.E.M. in units of ng/mL plasma. There are 2 – 5 dams per group, per time point. Plasma levels of COC, BE, and EME did not differ between postpartum days as a function of time after injection of cocaine. The time courses of plasma COC, BE, and EME were remarkably similar across postpartum days. Data are graphed in minutes after injection of cocaine.