title: A radioimmunoassay for the core fragment of the human chorionic gonadotropin beta-subunit.
abstract: We developed a RIA for the beta-core fragment of hCG that is excreted in the urine of pregnant women and some patients with cancer. We purified beta-core from crude commercial preparations of hCG (of which beta-core is a major constituent) derived from pregnancy urine and used this purified beta-core material to immunize rabbits. One antiserum (RW25) was particularly useful in that a RIA with purified beta-core as both radioligand and reference preparation had high sensitivity for beta-core detection and low cross-reactivity with other hCG-related molecules and glycoprotein hormones. The cross-reactivities of purified hCG (CR125), hCG beta (CR125), and hCG alpha (CR125) preparations were in each instance less than 3 x 10(-3) (wt/wt). The cross-reactivities of purified pituitary glycoprotein hormones were in each instance less than 2 x 10(-4) (wt/wt). Using the RW25 RIA, virtually all beta-core immunoreactivity in pregnancy urine eluted from Sephadex G-100 in a position coincident with that of purified beta-core. Urine from men and nonpregnant women contained very low levels of beta-core immunoreactivity (less than 6.5 micrograms/L), while urine from pregnant women and patients with testicular cancer or other neoplasms had levels of beta-core immunoreactivity ranging as high as 26,000 micrograms/L. We conclude that the improved specificity of our beta-core RIA will facilitate studies of the physiology and cancer biology of beta-core molecules.
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000906:Antibodies; D000918:Antibody Specificity; D002648:Child; D002675:Child, Preschool; D006063:Chorionic Gonadotropin / Q000652:urine*; D018997:Chorionic Gonadotropin, beta Subunit, Human; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000652:urine*; D011247:Pregnancy; D011817:Rabbits; D011863:Radioimmunoassay / Q000379:methods
chemical_list: D000906:Antibodies; D006063:Chorionic Gonadotropin; D018997:Chorionic Gonadotropin, beta Subunit, Human; D010446:Peptide Fragments