Phenethylamine in normal urine: failure to verify high values.

The phenethylamine (PEA) level in daytime urine samples of 18 normal subjects was measured by an isotope dilution technique. Purification of PEA from other urinary substance, after the addition of 1-14C-PEA to urine samples, was achieved by the sequence: thin-layer chromatography (TLC), derivatization, TLC, and finally, gas chromatography (electron capture). The estimated mean daily output of PEA was 10.3 mug/day. A circadian rhythm was not evident on the basis of analyses of 24-hr urine collections from four normal subjects. Three acute schizophrenics had levels within the normal means.