Size heterogeneity and specific binding property of immunoreactive prolactin in human seminal plasma

Abstract

Following gel filtration on a Sephadex G-100 column, and radioimmunoassay of the effluent fractions, seminal plasma samples from fertile men appeared to possess three discrete immunoreactive prolactin (IR-Prl) components analogous to those of normal serum and pituitary extract and an additional minor component which was eluted after ribonuclease. Furthermore, IR-Prl seminal plasma was predominantly recovered from the column in the high molecular size region, while in the serum and pituitary extract much of the activity was coeluted with monomeric hPrl (purified). Rechromatography of IR-Prl components in seminal plasma provided no evidence of the conversion of one component into the other. Examination of these different components of IR-Prl by means of radioreceptor assay (RRA) indicated that the highly retarded component exhibited no RRA activity. The other three components differed in their drgrees of RRA activity.