The passage of 14C-delta-9-tetrahydrocannabinol into the milk of lactating squirrel monkeys

Lactating squirrel monkeys chronically receiving 2 mg/kg delta-9-tetrahydrocannabinol (THC) orally either two or five times weekly were given a tracer dose of 14C-delta-9-THC mixed with the delta-9-THC. This permitted radioquantitation of the THC in milk specimens collected 1 to 24 hr after administration of the labeled dose. Correlated specimens of urine and feces were also collected individually from mothers and infants and were subjected to radioquantitation and exploratory TLC. During the 24-hr observation period, approximately 0.2% of the labeled delta-9-THC appeared in the milk, whereas 42% and 1% were excreted in the feces and urine, respectively. Infants that suckled during the 6 hr immediately after their mothers were administered the labeled compound excreted an average of 0.01% and 0.12% of the mother's dose in the urine and feces, respectively, during the 18 hr after suckling.