HUMAN PITUITARY PROLACTIN DURING PREGNANCY AND POST PARTUM AS MEASURED IN SERUM BY A RADIOIMMUNOASSAY

Abstract

Human pituitary prolactin (HPr) was measured using its cross reaction with sheep prolactin in a radioimmunoassay initially developed by Davis et al. (1971). The proposed system has been proved to be suitable for specific measurement of HPr contained in 200 μl of human serum (Midgley and L’Hermite; to be published). There was no inhibition of the binding of the tracer (highly purified ovine prolactin; LER-860-2) to the anti-ovine prolactin serum by as much as 2500 IU of human chorionic gonadotrophin (Commercial HCG, Roussel), 500 ng of human growth hormone (HGH-HS1394) and 10 μg of human chorionic somatomammotropin (HCS, Lederle 717.340). Immunoreactive HPr was measured in serum with reference to a pool of serum collected from pregnant women. This pool was temporarily used as laboratory standard. An immunological activity of 1.0 Unit (U) has been arbitrarily attributed to the amount of HPr contained in 1.0 ml of this pool.