Alpha Subunit of Glycoprotein Hormone: Presence in Peripheral Serum after LHRH

Abstract. A method is described for the selective measurement of human luteinizing hormone (hLH) and a subunit. The assays employ highly purified tracers of hLH and of subunit of human chorionic gonadotropin (hCGa) 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 125I‐labelled hLH as tracer, the assay recognize hLH, hCG and their β subunits 20–50 times more sensitively than hCGa. 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 125I‐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.

[1]  J. Bell,et al.  Alpha chain of glycoprotein hormones: presence in human serum after thyroid stimulating hormone releasing hormone. , 1973, The Journal of clinical endocrinology and metabolism.

[2]  S. Schwartz,et al.  Multiple antigenic and biological determinants of human FSH and its subunits. , 1973, Nature: New biology.

[3]  M. Laburthe,et al.  EVIDENCE FOR CIRCULATING α SUBUNITS OF PITUITARY GONADOTROPINS IN PLASMA. , 1973 .

[4]  G. Braunstein,et al.  Ectopic production of human chorionic gonadotrophin by neoplasms. , 1973, Annals of internal medicine.

[5]  W. Polishuk,et al.  Isolated deficiency of follicle-stimulating hormone. Clinical and laboratory features. , 1972, The New England journal of medicine.

[6]  P. Franchimont,et al.  POLYMORPHISM OF PROTEIN AND POLYPEPTIDE HORMONES 1 , 1972, Clinical endocrinology.

[7]  L. Reichert.  Biological studies on the relatedness of subunits of human follicle stimulating hormone and chorionic gonadotropin. , 1972, Endocrinology.

[8]  K. Catt,et al.  Radioligand-receptor assay of luteinizing hormone and chorionic gonadotropin. , 1972, The Journal of clinical endocrinology and metabolism.

[9]  R. Canfield,et al.  Nature of the subunits of human chorionic gonadotropin. , 1971, Endocrinology.

[10]  S. M. Howard,et al.  Studies on the structure of thyrotropin: its relationship to luteinizing hormone. , 1971, Recent progress in hormone research.

[11]  S. Hanlon,et al.  Some physical and hydrodynamic properties of human FSH and LH. , 1970, Recent progress in hormone research.

[12]  J. Porath,et al.  Chemical Coupling of Peptides and Proteins to Polysaccharides by Means of Cyanogen Halides , 1967, Nature.

[13]  T. Laurent,et al.  A theory of gel filtration and its exeperimental verification , 1964 .

[14]  F. Greenwood,et al.  THE PREPARATION OF I-131-LABELLED HUMAN GROWTH HORMONE OF HIGH SPECIFIC RADIOACTIVITY. , 1963, The Biochemical journal.