Radioimmunoassay of human beta-lipotropin in unextracted plasma.

A sensitive and specific radioimmunoassay for human beta-lipotropin (betah-LPH) in unextracted plasma was developed using pur betah-LPH as tracer and standard and an antiserum not cross-reacting with human beta-MSH and hACTH. In healthy volunteers plasma betah-LPH ranged from less than 20 to 150 pg/ml at 8:00 a.m. and rose after metyrapone administration. betah-LPH was very low in panhypopituitarism, normal in most patients with untreated Cushing's disease, elevated in acromegaly and extremely high in Nelson's syndrome.