Dams were dosed by gavage daily from GD 14 to GD 18 (fetal differentiation of androgen-dependent tissues) with PZ in corn oil at doses of 0, 31.25, 62.5, 125, or 250 mg/kg BW in a dose volume of 2.5 ml corn oil/kg BW. Treatment volume was calculated according to each dam’s daily weight. Dams were dosed by gavage using a 1.5-inch X 20-gauge curved feeding needle (7910; Popper and Sons, Lincoln, RI) attached to a 1-ml glass syringe.
Parturition and Offspring
Normally, the Sprague Dawley rat has a gestation duration of about 22.5 days. In this study, we designated the scheduled delivery date of PCD 23 as Postnatal Day (PND) 1. On PCD 23 we repeatedly checked the litters to determine the time of complete parturition for each litter. Nursing dams with clean pups were considered to have completed delivery. Five sets of observations (at times 0720, 1130, 1340, 1650, and 2130 h) were made on PCD 23. Four sets of observations (at times 0700, 1115, 1200, and 1510 h) were made on PCD 24. Two sets of observations (at times 0700 and 0930 h) were made on PCD 25. The time of first observation was considered to be time zero.