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Alpha Subunit of Glycoprotein Hormone: Presence in Peripheral Serum after LHRH
Author(s) -
Benveniste R.,
Frohman L. A.,
Bell J.,
Spitz I.,
Rabinowitz David
Publication year - 1975
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/j.1365-2362.1975.tb02277.x
Subject(s) - population , luteinizing hormone , human chorionic gonadotropin , antibody , sephadex , protein subunit , endocrinology , hormone , medicine , chemistry , g alpha subunit , biology , immunology , biochemistry , enzyme , environmental health , gene
. A method is described for the selective measurement of human luteinizing hormone (hLH) and α subunit. The assays employ highly purified tracers of hLH and of subunit of human chorionic gonadotropin (hCGα) and a “mixed population” of antibody: Population I (directed against determinants on β subunit of hCG) and Population II (directed against determinants on a subunit of hCG). The former is present in greater concentration than the latter. When the mixed antibody is used at high dilution (1:1.2 × 106), Population II is effectively diluted out, and using 125 I‐labelled hLH as tracer, the assay recognize hLH, hCG and their β subunits 20–50 times more sensitively than hCGα. When the mixed antibody is used at fivefold higher concentration, Population I is present in relative excess and acts as a “sink” for hCG, hLH and their β subunits. Under these conditions, using 125 I‐hCGα as tracer, the assay recognize the α subunit 20 to 50‐fold more sensitively than hLH and hCG. These assays have been employed in the study of sera which have been filtered over Sephadex G‐100. Alpha subunit was detected in serum within minutes after intravenous injection of luteinizing hormone releasing hormone (LHRH) in four subjects tested.