Intersex difference in striatal amphetamine concentration is independent of age

Amphetamine sulfate (1.0 mg/kg) was administered intraperitoneally to two groups of male and female rats, 5 and 15 weeks of age. After 30 minutes, striata were removed and analyzed for amphetamine concentrations using gas-liquid chromatography. Females were found to have significantly higher levels of amphetamine regardless of age. These results indicate that mechanisms other than drug disposition are responsible for the previously reported behavioral sex differences that occur after administration of amphetamine.