The development of a radioimmunoassay for cannabinoids in blood and urine.
Antibodies, for use in radioimmunoassay, have been raised in sheep by immunization with a conjugate of delta9-tetrahydrocannabinol hemisuccinate and bovine serum albumin. Antiserum titre and avidity were increased by successive booster doses of conjugate. The high degree of non-specific binding encountered in the radioimmunoassay of cannabinoids was reduced by the use of the solubilizing detergent Triton X-405 and by restricting protein concentration in the assay medium. Plasma samples were deproteinized with ethanol before assay, but urine was directly assayed. High avidity antibodies and high specific activity [3H]-delta9-tetrahydrocannabinol permitted the detection of 50 pg of cross-reacting cannabinoids--a sensitivity of 7-5 ng ml-1 of plasma and 1-0 ng ml-1 of urine. Whilst apparently specific for the three-ringed cannabinoid nucleus, the assay antiserum cross-reacted with several cannabinoids, both natural compounds and metabolites. Partial identification of cross-reacting cannabinoids was achieved by the use of pure compounds and by the assay of plasma and urine samples collected from rabbits given pure cannabinoids intravenously.
D000818:Animals; D000917:Antibody Formation; D000918:Antibody Specificity; D002188:Cannabis / Q000032:analysis* / Q000276:immunology; D002417:Cattle; D013759:Dronabinol / Q000032:analysis / Q000276:immunology; D011817:Rabbits / Q000276:immunology; D011863:Radioimmunoassay; D012710:Serum Albumin, Bovine; D012756:Sheep / Q000276:immunology; D013997:Time Factors
D012710:Serum Albumin, Bovine; D013759:Dronabinol