Human Chorionic Gonadotropin α-Subunit from Cultured Choriocarcinoma (JEG) Cells: Comparison of the Subunit Secreted Free with That Prepared from Secreted Human Chorionic Gonadotropin

The cultured human choriocarcinoma cell line, JEG-clone 3, secretes both biologically active hCG (JEG-hCG) and substantial quantities of free a-subunit (JEG-α). This study is concerned with a comparative characterization of the a-subunits of three distinct origins: 1) standard hCG-α obtained after dissociation of urinary (pregnancy) hCG, 2) JEG-α freely secreted by the JEG-3 cells, and 3) JEG-hCG-α obtained after dissociation of secreted JEG-hCG. Comparison of these a-subunits was made by gel exclusion chromatography, isoelectric focusing, and ability to form a radioreceptor assay-active hCG when incubated with standard hCG-β subunit. The freely secreted JEG-α exhibits an apparent molecular weight larger than that of standard hCG-a and JEG-hCG-α, whose apparent molecular weights are similar. The majority of JEG-α is represented by a component with acidic isoelectric pH (pI 4.8), and this component is virtually absent in standard hCG-α and JEG-hCG-α. When incubated with β-subunit, JEG-hCG-α forms a radiore...

[1]  D. Puett,et al.  Heterogeneity of the human chorionic gonadotropin alpha-subunit secreted by cultured choriocarcinoma (JEG) cells. , 1979, The Journal of clinical endocrinology and metabolism.

[2]  D. Puett,et al.  Characterization of the human chorionic gonadotrophin fractions in pregnancy urine. , 1978, Acta endocrinologica.

[3]  K. Speeg,et al.  Concanavalin-A stimulates human chorionic gonadotropin (hCG) and hCG-alpha secretion by human choriocarcinoma cells. , 1978, Biochemical and biophysical research communications.

[4]  J. Chou,et al.  Regulation of the synthesis of human chorionic gonadotrophin by 5-bromo-2'-deoxyuridine and dibutyryl cyclic AMP in trophoblastic and nontrophoblastic tumor cells. , 1978, The Journal of clinical endocrinology and metabolism.

[5]  B. Weintraub,et al.  Combination of ectopic and standard human glycoprotein hormone alpha with beta subunits: discordance of immunologic and receptor-binding activity. , 1977, Endocrinology.

[6]  R. Hussa.  Immunologic and physical characterization of human chorionic gonadotropin and its subunits in cultures of human malignant trophoblast. , 1977, The Journal of clinical endocrinology and metabolism.

[7]  H. Munro,et al.  Synthesis of human placental lactogen and human chorionic gonadotropin by polyribosomes and messenger RNA's from early and full term placentas. , 1976, The Journal of biological chemistry.

[8]  J. H. Morse,et al.  Human chorionic gonadotropin , 1976 .

[9]  G. Braunstein,et al.  Gonadotropins and their subunits: basic and clinical studies. , 1976, Recent progress in hormone research.

[10]  D. Puett,et al.  Gonadotropin and subunit conformation. , 1975, Archives of biochemistry and biophysics.

[11]  B. Weintraub,et al.  Differences between purified ectopic and normal alpha subnits of human glycoprotein hormones. , 1975, The Journal of clinical investigation.

[12]  J. Pierce,et al.  SECRETION OF ALPHA AND BETA SUBUNITS OF TSH BY THE ANTERIOR PITUITARY , 1975, Clinical endocrinology.

[13]  J. Pierce,et al.  Secretion of alpha subunits of luteinizing hormone (LH) by the anterior pituitary. , 1975, The Journal of clinical endocrinology and metabolism.

[14]  R. Canfield,et al.  The amino acid sequence of human chorionic gonadotropin. The alpha subunit and beta subunit. , 1975, The Journal of biological chemistry.

[15]  L. Frohman,et al.  Heterogeneity of purified human pituitary luteinizing hormone: effect on hormone measurement by radioimmunoassay. , 1975, Endocrinology.

[16]  B. Weintraub,et al.  Pituitary secretion of free alpha and beta subunit of human thyrotropin in patients with thyroid disorders. , 1975, The Journal of clinical endocrinology and metabolism.

[17]  L. Frohman,et al.  Alpha Subunit of Glycoprotein Hormone: Presence in Peripheral Serum after LHRH , 1975 .

[18]  J. Vaitukaitis.  Changing placental concentrations of human chorionic gonadotropin and its subunits during gestation. , 1974, The Journal of clinical endocrinology and metabolism.

[19]  O. P. Bahl,et al.  The role of carbohydrate in the biological function of human chorionic gonadotropin. , 1974, Current topics in molecular endocrinology.

[20]  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.

[21]  I. Spitz,et al.  Binding of human LH to particulate fraction of rat testis: disparity in LH:IRP equipotency ratios in immuno-and ligand assay. , 1973, Metabolism: clinical and experimental.

[22]  B. Weintraub,et al.  Competitive radioassays and "specific" tumor markers. , 1973, Metabolism: clinical and experimental.

[23]  S. Farmer,et al.  Studies on the structure and function of interstitial cell-stimulating hormone. , 1973, Recent progress in hormone research.

[24]  W. Liu,et al.  Chemical studies of luteinizing hormone from human and ovine pituitaries. , 1973, Recent progress in hormone research.

[25]  O. P. Bahl,et al.  Human chorionic gonadotropin. Linear amino acid sequence of the alpha subunit. , 1973, The Journal of biological chemistry.

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

[27]  D. V. van Thiel,et al.  Clonal lines of human choriocarcinoma cells in culture. , 1971, Acta endocrinologica. Supplementum.

[28]  E. Nieschlag,et al.  A method for producing specific antisera with small doses of immunogen. , 1971, The Journal of clinical endocrinology and metabolism.

[29]  R. Canfield,et al.  Studies of human chorionic gonadotropin. , 1971, Recent progress in hormone research.

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

[31]  O. P. Bahl,et al.  Dissociation and recombination of the subunits of human chorionic gonadotropin. , 1970, Biochemical and biophysical research communications.

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