Water was tested monthly for Pseudomonas and every 4 mo for a suite of chemicals, including pesticides and heavy metals. The current study was conducted under a protocol that had been approved by the National Health and Environmental Effects Research Laboratory institutional animal care and use committee.
In Vivo Dose Range-Finding Pilot Study
A preliminary dose range-finding study using two dams per treatment group and three vehicle-treated dams was conducted to select dose levels for the large-scale study. Dams and pups were reared as described in the main study. Dams were gavaged from GD 14 to GD 18 using PZ doses of 0, 62.5, 125, 250, and 500 mg/kg BW per day with a dose volume of 2.5 ml corn oil/kg BW. The high dose was not used in the subsequent definitive study because delivery was delayed extensively. No pups with 500 mg/kg BW treatment in the pilot study survived to Postcoital Day (PCD) 35, and treatment inhibited maternal weight gain in the dams.
When offspring of treated dams were necropsied (males from PCD 114 to 139, females from PCD 297 to 338), all animals were examined for phallus abnormalities. Males were examined for nipple retention; and anogenital distance, glans penis, and gubernacular cord length were measured.