Development and evaluation of a chromatographic procedure for partial purification of substance P with quantitation by an enzyme immunoassay

We have developed a simple chromatographic procedure for the partial purification of substance P (SP) from acidified plasma and serum samples. We have evaluated a sensitive antigen competition enzyme immunoassay (EIA) for the quantitation of SP. The chromatographic procedure has recovery efficiencies ranging from 94.8 to 125%. The immunoreactivity of unknown amounts of purified SP subjected to the preparative procedure yielded a coefficient of variance of 9.4%. The EIA yielded reproducible standard curves having an interassay (n = 8) correlation coefficient of 0.984. The evaluation of normal adult control serum yielded a mean value of 51 pg/ml (range, 35 to 61 pg/ml). The evaluation of 3.33 x concentrates of serum-derived partially purified SP provided uncorrected SP values of 117 to 201 pg/ml, which fell within the midpoint of the three-decalog standard curve. These studies indicate that both the preparative and quantitative procedures are required for the detection of SP in plasma or serum samples collected from patients with several clinical disorders.