Neohombreol

Cyproterone acetate (CAS number 427–51-0) was obtained from Berlex Laboratories, Montville, NJ, or Sigma, St. Louis, MO. Flutamide (CAS 13311–84-7) was obtained from Sigma. testosterone propionate (CAS 57–85-2) and testosterone (CAS 58–22-0) were obtained from Steraloids, Newport, RI, or Sigma. testosterone propionate solution for injection (50 mg/mL, Neohombreol) was obtained from Organon, Oss, Netherlands. Carboxymethylcellulose (CAS 9004–32-4) was obtained from Sigma. N-methyl-N-nitrosourea (MNU) (CAS 684–93-5) was obtained in re-crystallized form from Ash-Stevens, Detroit, MI, until its manufacture there was discontinued and it was obtained since in a non-recrystallized form from the NCI Chemical Carcinogen Repository, Midwest Research Institute, Kansas City, MO, and more recently from the MRIGlobal Chemical Carcinogen Repository, MRIGlobal, North Kansas City, MO.

Cyproterone acetate or flutamide was suspended in 2% aqueous carboxymethylcellulose for gavage administration at concentrations that would allow a gavage volume of 1 mL/rat or 10 mL/kg body weight. Testosterone propionate was suspended at 50 mg/mL in corn oil (Sigma) or as Neohombreol (Organon) for subcutaneous injection. The cyproterone acetate dose was 50 mg/kg/day, the dose of flutamide was 20 mg/kg/day, and the testosterone propionate dose was 100 mg/kg.