[Radioimmunoassay of human prolactin]

The radioimmunological dosage of human prolactin using the hormone as tracer and reference and an anti-prolactin antiserum is described. The labeling of human prolactin is carried out in the presence of a small quantity of chloramine T (10 mug). The purification of the labeled hormone is carried out by gel filtration on Sephadex G-75 or by polyacrylamide gel electrophoresis. The optimal incubation conditions were found using a first incubation of 40-48 hours at room temperatures followed by an incubation of 4 to 6 hours with cellulose-bound second antibody. The interference of serum proteins is small. There is no cross reaction with follicle stimulating hormone (FSH), luteinizing hormone (LH), thyroid stimulating hormone (TSH), human chorionic gonadotrophin (HCG), human placental lactogen (HPL) and human growth hormone (HGH). However, cross reaction with ovine, bovine and rat prolactin is found. These cross reactions are complete with endogenous human prolactin and hormone of different origin. Serum prolactin was determined in normal subjects and subjects treated with TRH and bromoergocryptine.