title: [A simple and direct radioimmunoassay for serum and urinary metanephrine].
abstract: A simple, direct and specific radioimmunoassay for serum and urinary metanephrine was developed, in which we used 125I-Synephrine and specific antiserum generated in rabbits by injecting with metanephrine conjugated with bovine serum albumin as described by Grota and Brown. The sensitivity of the assay was 2 pg/tube. Intra- and inter-assay coefficients of variation were 2.6 approximately 7.8% and 5.0 approximately 9.6%, respectively. The recoveries of metanephrine added at two levels of 250 pg/ml and 500 pg/ml to ten serum samples and ten urine samples (hydrolyzed and diluted) were 96.7 and 108% in serum, and 94.8 and 103% in urine, respectively. Normal values of serum metanephrine were 40.3 +/- 25.8 pg/ml (mean +/- SD) from 20 normal subjects. Normal values of 24 hour urinary metanephrine excretion were 12.5 +/- 6.7 ug/day from 24 normal subjects. Serum metanephrine values for 7 patients with pheochromocytoma were 210 approximately 628 pg/ml. Urinary metanephrine values for 9 patients with pheochromocytoma 8.7 approximately 302 ug/day.
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000032:analysis; D000328:Adult; D004837:Epinephrine / Q000031:analogs & derivatives*; D006801:Humans; D006973:Hypertension / Q000378:metabolism; D008676:Metanephrine / Q000032:analysis* / Q000097:blood / Q000652:urine; D010673:Pheochromocytoma / Q000032:analysis; D011863:Radioimmunoassay / Q000379:methods*
chemical_list: D008676:Metanephrine; D004837:Epinephrine