Radioimmunoassays of 3,4,5-trimethoxyphenethylamine (mescaline) and 2,5-dimethoxy-4-methylphenyl-isopropylamine(DOM)

Mescaline (3,4,5-trimethoxyphenethylamine) and N-succinylmescaline were coupled to human serum albumin with carbodiimide. DOM (2,5-dimethoxy-4-methylphenylisopropylamine) was linked to human serum albumin by reaction with glutaraldehyde. These conjugates were used for immunization of rabbits. Derivatives of mescaline [ N-(3′,4′,5′-trimethoxyphenethyl)-4-hydroxyphenylacetamide] and of DOM [ N-(2′,5′-dimethoxy-4′-methylphenylisopropyl)-4-hydroxyphenylacetamide], which could be iodinated to high specific activity, were synthesized. The antibodies bound specifically to these iodinated compounds. In competition experiments with a mescaline antiserum, 6 pmoles of mescaline inhibited 50%; with a DOM antiserum, 50% inhibition was observed with 118 pmoles of DOM. Thus, 100 pg of mescaline and 2 ng of DOM can be detected. The specificity of both antibodies is such that structurally related molecules, such as p-methoxy-phenethylamine or 3-methoxytyramine, are several orders of magnitude less effective as inhibitors than the parent molecules. With the use of antimescaline, it was determined that mescaline administered intravenously to rabbits disappeared rapidly from the circulation. The acid was identified as the major metabolite in the serum and urine of these animals.