pCi/mg) and unlabeled, pyrogen-free THC were supplied by the Na-tional Institute on Drug
Abuse.[G-" H] A"-THC (batch 9TRK446, 11.7 Ci/mmol), the internal standard for high
performance liquid chromatography (HPLC) was obtained from Amersham/Searle (Arlington
Heights, IL). Both labeled and unlabeled THC were purified by HPLC at least 3 days before
use and were mixed to yield 20 pCi/mg. HPLC solvents and other chemicals and reagents …