Radioimmunologic determination of the thyrotropin releasing hormone

: We describe the preliminary steps for a radio-immunoassay of Thyrotropin Releasing Hormone (TRH). Rabbit antiserum at dilution 1 : 10 000 is used with radioiodinated TRH (125I). We are able to assay from 5 to 1 000 pg unlabeled TRH with an intraassay reporducibility varying from 7 to 4 % and the lowest detectable amount in this system is 10 pg TRH. TRH mean and standard deviation in normal subjects are 136,9 and 25,3 pg/ml.