A teratogenicity study on hydroxyurea and diphenylhydantoin in cats

Area of Science:

• Veterinary Pharmacology
• Toxicology
• Developmental Biology

Background:

• Hydroxyurea is an antitumor drug with known teratogenic effects in multiple species.
• Diphenylhydantoin is a known teratogen in rodents.
• Assessing drug teratogenicity in cats is crucial for understanding potential risks.

Purpose of the Study:

• To evaluate the teratogenic potential of hydroxyurea and diphenylhydantoin in domestic cats.
• To determine the utility of the cat as an animal model for drug teratogenicity screening.

Main Methods:

• Pregnant cats were administered oral doses of hydroxyurea (50 or 100 mg/kg) or sodium diphenylhydantoin (1 or 2 mg/kg) from gestation days 10-22.
• Control groups received empty capsules.
• Cats were necropsied on gestation day 43, and fetuses were examined for malformations.

Main Results:

• Hydroxyurea (50 mg/kg) showed low teratogenic activity; higher doses (100 mg/kg) led to non-pregnancy and resorptions.
• Diphenylhydantoin did not demonstrate clear teratogenicity but was embryolethal at a maternally toxic dose (2 mg/kg).

Conclusions:

• The cat appears to be a useful species for screening drugs and chemicals for teratogenic potential.
• Further research may elucidate specific mechanisms of teratogenicity in feline models.