Distribution and occurrence of amphetamine and p-hydroxyamphetamine in tissues of the rat after injection of d-amphetamine sulfate.

The distribution of amphetamine and the formation and distribution of its principal metabolite p-hydroxyamphetamine after the injection of relatively small amounts of d-amphetamine was examined in the rat. Amphetamine entered all organs readily and was rapidly eliminated. p-Hydroxyamphetamine was rapidly synthesised and it is suggested that substrate inhibition of hepatic hydroxylating enzymes occurs. In the brain, amphetamine was homogeneously distributed between the seven brain regions examined whereas p-hydroxyamphetamine was predominantly concentrated in the striatum.