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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An endodermal sinus (yolk sac) tumor was successfully transplanted into athymic nude mice. Histologic and ultrastructural investigations revealed that the transplanted tumor had a characteristic appearance with numerous Shiller-Duval bodies, endodermal sinus structures and ultrastructural profiles as previously described in human material. The endodermal sinus tumor and normal human yolk sac have been found to synthesize not only alpha-fetoprotein (AFP), but also other serum proteins, namely, albumin, prealbumin, alpha 1-antitrypsin, and transferrin. Serological study by radioimmunoassay demonstrated AFP, carcinoembryonic antigen (CEA) and human chorionic gonadotropin (HCG) in the sera of the tumor-bearing nude mice and in cyst fluid from the transplanted tumor. Immunohistochemical investigation using the unlabeled antibody peroxidase-antiperoxidase method showed using the unlabeled antibody peroxidase-antiperoxidase method showed that the tumor cells produced CEA, alpha 1-antitrypsin, transferrin, HCG as well as AFP. These immunohistochemical staining properties were correlated with the findings on radioimmunoassay.
Virchows Arch B Cell Pathol Incl Mol Pathol 1981
PMID:Ultrastructure and immunohistochemical staining of a transplanted endodermal sinus tumor. 617 98

Sertoli cells in primary cultures produce plasminogen activator activity, and release it into the medium at rates greatly influenced by a variety of factors, including cell density, the presence of hormones, incubation temperature and duration of culture. In Sertoli cells maintained in culture in the presence of dibutyryl cAMP, the amounts of plasminogen activator activity secreted per cells were maximal at cell densities up to 2.5 microgram DNA/cm2 (350 units/microgram cell DNA), and declined to 40 units/microgran cell DNA at a density of 22 micrograms DNA/cm2. Concentrations of follicle-stimulating hormone (FSH) required to elicit half-maximal stimulation of the production of plasminogen activator activity were 0.37 micrograms/ml for oFSH-NIH S12 and 8 ng/ml for the more purified of SH-S1528C2. The ED50 for dibutyryl cAMP was found to be 0.08 mM. Addition of an inhibitor of phosphodiesterase (3-isobutyl-l-methylxanthine) enhanced the formation of plasminogen activator by cells cultured in the presence of FSH. Addition to the culture medium of testosterone, epidermal growth factor, insulin, human chorionic gonadotropin or prostaglandins (E1, E2 or F1 alpha) did not result in increased production of PA activity by Sertoli cells. Cells in culture for as long as 14 days remained responsive to FSH or dibutyryl cAMP. Increases in cellular levels of plasminogen activator became evident within 2-4 after addition of either FSH or dibutyryl cAMP to the medium. The stimulation of FSH or dibutyryl cAMP of the production of plasminogen activator activity was shown to be dependent upon de novo synthesis of RNA and protein. Levels of enzyme activity released by Sertoli cells maintained in culture for 48 h at 37 degrees C were approx. 50% higher than plasminogen activator released by cells cultured at 32 degrees C. The control of the production of plasminogen activator activity by Sertoli cells was discussed in relation to the control of plasminogen activator production by granulose cells, and the possible role of plasminogen activator in gonadal functions.
Mol Cell Endocrinol 1982 May
PMID:The control of the synthesis and secretion of plasminogen activator by rat sertoli cells in culture. 617 77

Mixtures of some but not all monoclonal antibodies which bind to separate epitopes on human chorionic gonadotropin (hCG) show an increased affinity for the hormone. To find an explanation for the increase in affinity, we developed a mathematical model which predicts the quantities of intermediates formed when pairs of IgG1 mouse monoclonal antibodies having affinities of approximately 10(8) M-1 for hCG are mixed with the hormone. At low antibody concentrations (i.e. less than 1 nM or 0.15 micrograms/ml) analysis of possible antibody-hormone combinations, including linear and circular chains composed of less than 12 molecules of antibody and 12 molecules of hCG, suggests the increase in affinity is due to formation of a circular complex containing two molecules of antibody and two of hCG. Further, the model predicts that the circular complex will be the major species formed at antibody-antigen equivalence. This prediction is supported by experimental observations on the molecular weight of a new complex formed in the presence of hCG and the mixture of the monoclonal antibodies. In addition, based on experimental values of binding constants for individual antibodies to hCG, the model correctly quantifies the loss in complex observed in the presence of excess hCG antigen. At high antibody concentrations (i.e. greater than 10 nM or 1.5 micrograms/ml) the formation of linear chains of antibody hCG pairs becomes appreciable and contributes to the increase in apparent affinity of the mixture for hCG. These results suggest that the observed affinity of complex mixtures of antibody for antigens containing multiple epitopes calculated from Scatchard plots may not be related to the affinity or avidity of any of the antibody species for a given epitope.
Mol Immunol 1983 Apr
PMID:Quantitative explanation for increased affinity shown by mixtures of monoclonal antibodies: importance of a circular complex. 619 Dec 9

The present paper examines the steroidogenic responsiveness of immature porcine Leydig cells in primary culture. Both testosterone (T) and dehydroepiandrosterone sulfate (DHAS) secretion were measured under basal conditions and after stimulation with human chorionic gonadotropin (hCG) (25 ng/ml). In medium supplemented with insulin, transferrin, epidermal growth factor (3H) and 0.1% calf serum, cells survived 3-5 days in culture. The production of steroids (under hCG stimulation) is poor on day 0-1 of the culture. On day 2-4 basal T and DHAS levels are 1.9 and 17.0 ng/10(6) cells/24 h. The addition of hCG stimulated T and DHAS production 19- and 6-fold respectively and the average productions were 37 and 109 ng/10(6) cells/24 h. Increasing the serum to 0.5% did not change the viability of the cultures, but increased hCG stimulated T and DHAS production (183 and 188 ng/10(6) cells/24 h). The addition of alpha-tocopherol (vitamin E) to 0.1% calf serum led to a 4-fold increase in stimulated T production (142 ng/10(6) cells/24 h) and maintained full cell viability for more than 5 days. Measurement of 3 beta-ol steroid dehydrogenase activity indicates that the amount of enzyme is 4 times higher at day 2 than at day 0 and 1 (with or without hCG), suggesting a spontaneous maturation of the cells in culture. This might explain the increased T production with time in culture. In cumulative experiments (24 h) the cells do not seem to be desensitized to hCG stimulation following prolonged exposure to 25 ng hCG since the daily steroid production is increasing with time in culture. However, kinetic studies show that steroidogenesis is not linear over a 24 h period. In cumulative experiments the steroid production stops between 12 and 16 h following hCG exposure (5 and 100 ng/ml) and resumes following a medium change. These results suggest that some inhibitory compounds are accumulated in the medium and are controlling the Leydig cell function. Moreover high doses of hCG (100 ng/ml) result in a lower production of steroids and an earlier plateau in the case of DHAS. These results demonstrate that porcine Leydig cells can live and differentiate in hormone- and vitamin-supplemented medium and that auto-feedback mechanisms inhibiting steroid accumulation take place under in vitro conditions.
Mol Cell Endocrinol 1983 Apr
PMID:Androgen production in primary culture of immature porcine Leydig cells. 622 Sep 34

Treatment of purified rat ovarian plasma membranes with N,N'-dicyclohexylcarbodiimide (DCC) abolishes the subsequent response of adenylate cyclase [EC 4.6.1.1, ATP pyrophosphate lyase (cyclizing)] to lutropin (LH) and follitropin (FSH) but not to NaF. Such treatment also inhibits binding to these membranes of iodinated [125I] human chorionic gonadotropin (125I-hCG). Preincubation for 30 min at room temperature with 70 microM DCC reduces the response of adenylate cyclase to LH by 50% whereas 4 times higher concentration is required to reduce 125I-hCG binding to the same extent. At 0.5 mM, DCC reduces both activities by 50% within 8-10 min. Preincubation of the membranes with hCG prior to treatment with DCC protects the hormone-binding site of the receptor but not the ability of the enzyme to respond to LH. Thus the enzyme becomes functionally uncoupled. It is suggested that at least two distinct sites in the enzyme system are affected by DCC. Both sites are located proximal to the regulatory step that involves GTP-binding protein. One site seems to be associated with the receptor and the second is located distal to receptor-hormone complex formation.
Mol Cell Endocrinol 1980 Apr
PMID:Uncoupling of gonadotropin-sensitive adenylate cyclase by N,N'-dicyclohexylcarbodiimide. Evidence for modification of two sites. 624 96

An evaluation of several techniques commonly used to separate bound from free hormone was made for the binding of radiolabelled human chorionic gonadotropin to mid-luteal pig corpus luteum homogenates and subcellular fractions. Compared to millipore filtration with 0.22 or 0.45-mu HAWP filters, centrifugation of homogenates at 2 500 x gav or 1 000 x gav for 15 min recovered only 50 and 33% respectively of the total bound hormone present. This discrepancy was accentuated further when hormone binding to post-nuclear subcellular fractions was studied. Centrifugation of a nuclear fraction at 2 500 x gav for 15 min recovered 70% of the membrane-bound receptors present (as measured by filtration), whereas centrifugation of mitochondrial, lysosomal and microsomal fractions under these conditions recovered only 46, 16 and 4% respectively. Divalent metal ions influenced hormone binding in 2 ways: (i) Specific bonding of hCG was greatest in the absence of metal ions and in the presence of low levels of chelating agents. Increasing concentrations of magnesium and calcium ions appeared to interfere with the interaction of hormone and receptor. (ii) Divalent metal ions reduced the recovery of particle-bound hormone by centrifugation, at both high and low speeds. The results illustrate the pitfalls of using low-speed centrifugation to recover membrane-bound hormone-receptor complexes when small membrane vesicles are present.
Mol Cell Endocrinol 1981 Oct
PMID:Properties of LH/hCG receptors in porcine corpus luteum homogenates and subcellular fractions, and factors influencing the recovery of membrane-bound hormone. 627 45

The gene encoding the common alpha subunit of the four human glycoprotein hormones, chorionic gonadotropin (CG), luteinizing hormone (LH), follicle stimulating hormone (FSH), and thyroid stimulating hormone (TSH), has been cloned in a bacteriophage lambda vector. Restriction endonuclease digestion of total human DNA suggests that the common alpha subunit is coded for by a single gene. Three distinct polymorphic hybridization patterns have been observed for this gene in the human population. The cloned gene encompasses a total of 9.4 kilobases (kb) and contains three intervening sequences whose locations have been established by restriction enzyme mapping and by DNA sequencing. One of the intervening sequences is located in the 5' untranslated region, generating a leader sequence that is separated from the rest of the gene by 6.4 kb. The other two intervening sequences are 1.7 and 0.4 kb long and are located within codon number 6, and between codons 67 and 68, respectively. The location of the 5' end of the mature transcript has been established by priming placental mRNA with a restriction fragment obtained from the cloned cDNA. A transcript of similar size for the alpha subunit gene has been detected in both the pituitary, where the gene is expressed for the synthesis of LH, FSH, and TSH, and the placenta, where the gene is expressed for the synthesis of CG. When parts of the 5' untranslated nucleotide sequences of the alpha subunit and the human growth hormone genes are compared a highly homologous region is observed. These otherwise unrelated genes share the common feature that they encode a secreted pituitary polypeptide hormone.
J Mol Appl Genet 1981
PMID:The gene encoding the common alpha subunit of the four human glycoprotein hormones. 628 17

The v-src gene was removed from Rous sarcoma virus DNA and replaced with either a cDNA or genomic clone of human alpha-chorionic gonadotropin. Transfection of the recombinant retrovirus genomes into normal chicken fibroblasts produced nontransforming recombinant virus in high titer. Neither helper virus nor selective conditions were needed. Cells infected with the recombinant viruses expressed RNA containing the gonadotropin sequences in levels equivalent to those of term human placenta (approximately 0.5% of poly A+). Essentially every fibroblast in the culture was infected; the infected cells contained approximately one recombinant provirus each. The gonadotropin intervening sequences were removed precisely from the recombinant genomes that contained them, creating recombinants carrying a perfect cDNA copy of the original genomic insert. However, the intervening sequences were removed inefficiently such that several viral replicative cycles were necessary before all genomes had been processed completely. The implications of these observations to the transduction of viral oncogenes and the creation of processed pseudogenes are discussed.
J Mol Appl Genet 1982
PMID:Splicing of intervening sequences introduced into an infectious retroviral vector. 629 56

Rat ovarian epidermal growth factor (EGF) receptors were characterized in total ovarian homogenate obtained from animals at random stages of the estrous cycle. A single class of specific and high-affinity binding sites with an apparent dissociation constant (KD) of 1.1 +/- 0.2 nM and a total site number of 78 +/- 4 fmoles/mg protein (652 +/- 17 fmoles/100 mg wet tissue) was observed. In 4-day cycling rats, ovarian EGF receptor levels are high (200 fmoles/100 mg ovary) on the morning of estrus as well as in the afternoon of proestrus and are lower by 30, 60 and 55% on the morning of diestrus I, diestrus II and proestrus, respectively. Chronic administration of an LHRH agonist is accompanied by low ovarian EGF receptor levels comparable to those observed on diestrus II. In intact or hypophysectomized female rats pretreated with pregnant mare's serum gonadotropins, administration of ovine follicle-stimulating hormone or human chorionic gonadotropin increases ovarian EGF receptor concentration and content while the administration of ovine prolactin, 17 beta-estradiol or progesterone has no effect. Treatment with dihydrotestosterone or testosterone slightly reduces ovarian EGF binding in intact but not hypophysectomized animals. The variation of ovarian EGF receptor levels observed during the estrous cycle as well as the modulation of these receptors by the administration of exogenous gonadotropins suggest that EGF could well play a physiological role in the regulation of ovarian functions.
Mol Cell Endocrinol 1983 Jul
PMID:Rat ovarian epidermal growth factor receptors: characterization and hormonal regulation. 630 84

Granulosa and theca cells obtained from patients were isolated and cultivated in a chemically defined medium containing gonadotropins and/or testosterone. Progesterone secretion by granulosa cells was consistently stimulated (2-40-fold) in all 5 patients by the addition of follicle-stimulating hormone (FSH, 0.25 micrograms/ml). In the presence of testosterone (0.5 micro M) alone, progesterone production was stimulated (2-8-fold) in 4 out of the 5 patients and cells of one patient showed a greater response to testosterone than to FSH alone. In 2 of the 5 patients, it was also noted that FSH and testosterone acted in a synergistic manner to stimulate the production of progesterone by granulosa cells. On the other hand, human chorionic gonadotropin (hCG, 1.0 IU/ml) alone failed to exert any significant effect. None of the treatments examined altered the production of progesterone by theca cells. These results suggest a role for FSH and testosterone in regulating progesterone biosynthesis by granulosa cells of the human ovary during follicular development.
Mol Cell Endocrinol 1981 Jul
PMID:The role of gonadotropins and testosterone in progesterone production by human ovarian granulosa cells. 679 Mar 15


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