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PubMed1981

Use of the radioreceptor assay for human chorionic gonadotropin in the diagnosis of ectopic pregnancy.

Since unrecognized ectopic pregnancy is a potentially lethal condition, there is a need for an accurate, rapid, sensitive and specific method for measuring low levels of human chorionic gonadotropin that may be observed in ectopic pregnancy. The Biocept-G test is a commercial modification of the radioreceptor assay for human chorionic gonadotropin. The test is performed in one hour and has a sensitivity of 200 milliinternational units of human chorionic gonadotropin per milliliter of serum. This study consisted of 15 patients with proved tubal ectopic pregnancies who were evaluated with the Biocept-G assay. All of the patients had a positive test result. By comparison, the two hour urine tube test result was positive in only eight and negative in seven patients. The two minute urine slide test result was positive in only six and negative in nine patients. The Biocept-G test was found to be simple to perform, quick and reliable, and the cost was comparable with that of the less accurate immunoassays. With the advent of the radioreceptor assay for human chorionic gonadotropin and the radioimmunoassays for the beta subunit of human chorionic gonadotropin, the presence of a positive pregnancy test result may be the most reliable diagnostic aid in helping to recognize early ectopic pregnancy.

Chorionic Gonadotropin↗
PubMed1996

A recombination-efficient baculovirus vector for simultaneous expression of multiple genes.

The baculovirus system is an extremely powerful tool for expression of heterologous genes in eukaryotic environment. A multiple expression vector, pBacUCmP3, was constructed which harbored two copies of the Autographa californica nuclear polyhedrosis virus very late gene promoter and the Drosophila melanogaster 70-kDa heat-shock protein (hsp70) promoter with downstream unique restriction sites for cloning of three independent foreign genes. Co-transfection of pBacUCmP3 with Bsu36I-linearized viral DNA yields recombinant progeny viruses at very high frequencies. The utility of this multiple expression transfer vector was demonstrated using three heterologous reporter genes encoding the beta-subunit of the human chorionic gonadotropin hormone, firefly luciferase and the bacterial beta-galactosidase (beta Gal) enzyme. The expression of reporter genes, monitored at various times post-infection, confirmed that while beta-Gal synthesis was under the transcriptional control of the hsp70 promoter, the beta hCG and Luc proteins were synthesized as a function of polyhedrin promoter activation profile. This vector will be useful for multiple synthesis of proteins at different time points.

Animals↗
PubMed1980

A possible role for prolactin in the control of human chorionic gonadotropin and estrogen secretion by the fetoplacental unit.

The effects of prolactin (PRL) on fetoplacental function were studied by measuring the beta subunit of human chorionic gonadotropin (hCG-beta), estradiol (E2), progesterone (P), and PRL concentrations throughout seven pregnancies in a control group (N = 6 women) and in three pregnant women with prolactinomas, who were receiving bromocriptine. In one of the latter, estriol (E3) was also assayed. Long-term suppression of PRL was associated with augmentation of hCG-beta at the first-treimester peak and in late pregnancy. Concomitant augmentation of E3 (in late gestation) and possibly E2, but not P, levels was also observed. This effect on hCG appeared dependent on PRL rather than the dopaminergic effect of bromocriptine. Short-term drug induced alterations in PRL (over 3 hours) during early pregnancy did not result in significant changes in hCG-beta or steroid concentrations. In each control pregnancy, a significant negative correlation (p less than 0.05) was observed between hCG-beta and PRL, while a significant positive correlation between the latter and E2 concentrations in these women was also demonstrated. Apart from its effect on lactation, osmoregulation, and gonadal and adrenal function, a further role for PRL during reproduction appears to be in the control of hCG and estrogen secretion in the fetoplacental unit.

Adult↗
PubMed1986

Carcinoembryonic antigen and beta-human chorionic gonadotropin as serum markers for advanced urothelial malignancies.

Serum levels of carcinoembryonic antigen and beta-subunit of human chorionic gonadotropin were measured in 92 patients with advanced urothelial malignancies referred to us for chemotherapy. Elevations of carcinoembryonic antigen and/or beta-human chorionic gonadotropin occurred in 60 of the 92 patients (65 per cent). Minimal elevations (less than 50 per cent above the normal range) occurred in 25 patients (27 per cent), while 35 (38 per cent) had significant elevations (more than 50 per cent above the normal range). Of the latter patients carcinoembryonic antigen alone was elevated in 16 (17 per cent), beta-human chorionic gonadotropin alone in 13 (14 per cent) and both in 6 (6 per cent). Among the 24 patients with initially elevated levels whose markers were re-evaluated during therapy the marker levels correlated with disease course in all 15 whose elevations were more than 50 per cent and in 4 of 9 with minimal elevations. In patients with adenocarcinoma of the bladder the carcinoembryonic antigen level frequently was elevated (9 of 10). We conclude that serum levels of carcinoembryonic antigen or beta-human chorionic gonadotropin are significantly elevated (more than 50 per cent above the normal range) in 38 per cent of the patients with advanced urothelial malignancies and can be used as tumor markers, since they correlate with the clinical course of the patient and the response to therapy. Serum carcinoembryonic antigen levels usually are elevated in patients with bladder adenocarcinoma.

Adenocarcinoma↗
PubMed1979

Ectopic production of human chorionic gonadotropin: a case report.

The ectopic production of the beta-subunit of human chorionic gonadotropin (hCG) is described in a patient with an anaplastic carcinoma. After chemotherapy the marker decreased in a logarithmic fashion to undetectable levels but the neoplasm progressed and the patient died. The specificity of the beta-subunit of hCG is discussed. Discordance of the marker and clinical disease is pointed out, and several possible explanations are outlined. The lack of specificity of the beta-subunit of hCG and the discordance that it may exhibit means that its use in diagnosing and following disease progression may be limited.

Adult↗
PubMedDate not supplied

2nd-trimester maternal serum marker results are not altered by delayed analysis.

OBJECTIVE: The goal of the study was to evaluate the significance of delayed laboratory analysis of maternal serum alpha-fetoprotein, beta-subunit of human chorionic gonadotropin, and unconjugated estriol for prenatal screening. METHODS: Biochemical analysis of 30 consecutive biochemical screening specimens of maternal serum alpha-fetoprotein, beta-subunit of human chorionic gonadotropin, and unconjugated estriol was performed immediately upon arrival to the laboratory, 7 days later, and again 14 days after maternal blood was drawn. Differences among the results of the three sets of biochemical studies were evaluated by one-way analysis of variance for repeated measures. RESULTS: No significant differences were found among the results of immediate assays as compared with those at a 7- or a 14-day delay for all three biochemical markers. CONCLUSIONS: Our data suggest that up to a 14-day delay in the performance of the 2nd-trimester maternal serum biochemical screening assays will not alter the results significantly. The results of maternal serum screening are, thus, clinically valid even if the laboratory assays were performed several days after maternal blood was drawn.

Adolescent↗
PubMed1992

Molecular basis of recognition by the glycoprotein hormone-specific N-acetylgalactosamine-transferase.

Lutropin (LH) bears asparagine-linked oligosaccharides terminating with the unique sequence SO4-4GalNAc beta 1-4GlcNAc beta 1-2Man alpha, whereas follitropin (FSH) bears oligosaccharides terminating predominantly with the sequence Sia alpha-Gal beta 1-4GlcNAc beta 1-2Man alpha, where Sia is sialic acid. We previously identified a glycoprotein-hormone-specific N-acetylgalactosamine-transferase (GalNAc-transferase) that recognizes a peptide-recognition marker(s) present on the common glycoprotein hormone alpha subunit and beta subunits of human chorionic gonadotropin and LH but not on the beta subunit of FSH. We have now identified an amino acid sequence motif, Pro-Leu-Arg, that is essential for recognition by the GalNAc-transferase. This tripeptide sequence is found 6-9 residues on the amino-terminal side of a glycosylated asparagine on the alpha subunit and beta subunits of LH and human chorionic gonadotropin but is not present on the beta subunit of FSH. The presence of this motif accounts for the differences in LH and FSH oligosaccharide structures. Additional proteins containing this recognition motif have been identified and were determined to bear sulfated oligosaccharides with the same structures as those on the glycoprotein hormones, indicating that these structures are not restricted to the glycoprotein hormones.

Amino Acid Sequence↗
PubMed1990

Evidence for the presence of human chorionic gonadotropin (hCG) and free beta-subunit of hCG in the human pituitary.

Previous studies have indicated that the pituitary gland may produce free alpha-subunit and small quantities of hCG in addition to other glycoprotein hormones. Since synthesis of holo-hCG requires the presence of both subunits, we have investigated the occurrence in human pituitary of free beta-subunit of hCG, in addition to intact holo-hCG. We processed a pituitary extract by fractionated ammonium sulfate precipitation followed by sequential chromatography on Sephadex G-100 and Ultrogel AcA 44. The fractions obtained were assessed for their reactivities with a panel of polyclonal and monoclonal antibodies specific for holo-hCG, beta-subunit of hCG, alpha-subunit, or hCG/LH. In addition to the expected LH and alpha-subunit, we detected materials which eluted from the column in positions very similar to those of cochromatographed 125I-hCG tracer and hCG-beta (NIH CR123-beta), and which showed immunoreactivity in specific immunoradiometric assays for holo-hCG and hCG-beta, respectively. Holo-hCG and hCG-beta material derived from the urine of a postmenopausal woman showed behaviors on the column similar to the pituitary forms. Both the pituitary holo-hCG- and free hCG-beta-subunit activity could be enriched (approximately 500 times) by affinity chromatography on an hCG antibody-coupled Sepharose column. When subjected to isoelectric focusing in granulated gel holo-hCG and hCG-beta-subunit of pituitary origin were focused in the pI-range of pregnancy hCG and pregnancy hCG-beta-subunit, respectively. Like pregnancy hCG, most (75%) of the pituitary hCG was bound to a column of Con A-Sepharose; however, the Con A-nonbinding hCG fraction (approximately 25%) was much higher than that found in pregnancy hCG. On the basis of immunoreactivities, the content of holo-hCG in our pituitary extract was estimated to be 60 micrograms/g, and that of free beta-subunit 45 micrograms/g; for comparison, LH was approximately 20 mg/g, and free alpha-subunit 1.6 mg/g. In addition, we could demonstrate the presence of both holo-hCG- and free hCG-beta-subunit-like immunoreactivity in NaCl-extracts from single pituitaries of two postmenopausal women. In these studies a second hCG-beta-immunoreactive material eluting far behind the hCG-beta-position was found. Chromatography of purified LH-beta-subunit, which crossreacts 1.56% in the hCG-beta IRMA, yielded an elution pattern clearly distinguishable from that of the hCG-beta-immunoreactive substances.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1988

Conformation of the beta subunit of deglycosylated human chorionic gonadotropin in the interaction at receptor sites.

The present study was performed to evaluate the relationship between the antagonist effect and the conformation of deglycosylated human chorionic gonadotropin (DGhCG) on the Leydig cell lutropin receptors. The maximum binding of [125I]DGhCG to anti-hCG beta antibody was decreased by 50%, while its binding profile to anti-hCG, anti-DGhCG and anti-hCG alpha antibodies remained unchanged, suggesting conformational changes in the beta subunit of DGhCG. However, the association of [125I]DGhCG to the binding sites of the receptors was much faster than that of [125I]hCG, and the ligand reached the binding equilibrium at 4 and 37 degrees C for 3 h and 15-30 min, respectively. Thus, the conformational changes in the beta subunit were not accompanied by loss of its receptor binding ability. The agonist properties of DGhCG which was bound to the receptors was fully restored by the addition of anti-hCG beta subunit antibody, while anti-hCG or anti-DGhCG restored only about 30% of the full agonist activity. This was probably due to a change of the conformation of the beta subunit to make it similar to that of the intact hormone. This restoration caused by anti-hCG beta was partially prevented by anti-hCG alpha. These facts indicate that some conformational change only in the beta subunit, not in the alpha subunit, of the deglycosylated hormone bound to the receptors is essential for the restoration of agonist properties.

Animals↗
PubMed1989

Heterotopic pregnancy associated with assisted reproductive technology.

The incidence of heterotopic pregnancy has been reported to be 1 per 30,000 pregnancies. This incidence may be much higher in pregnancies associated with assisted reproductive technology. Intravaginal ultrasonography and the use of quantitative beta-subunit assays of human chorionic gonadotropin should allow early diagnosis and treatment.

Abortion, Induced↗
PubMed1995

Biosynthesis of a biologically active single peptide chain containing the human common alpha and chorionic gonadotropin beta subunits in tandem.

One of the distinguishing features of the gonadotropin and thyrotropin hormone family is their heterodimeric structure, consisting of a common alpha subunit and a hormone-specific beta subunit. Subunit assembly is vital to the function of these hormones: The conformation of the heterodimer is essential for controlling secretion, hormone-specific posttranslational modifications, and signal transduction. To address whether alpha and beta subunits can be synthesized as one chain and also maintain biological activity, a chimera composed of the human chorionic gonadotropin (hCG) beta subunit genetically fused to the alpha subunit was constructed. The resulting polypeptide hCG molecule not only was efficiently secreted but also displayed an increased biological activity in vitro and in vivo. These data show that the alpha and hCG beta subunits encoded as a single chain retain a biologically active conformation similar to that seen in the heterodimer. This approach can be used to investigate structure-function relationships of the glycoprotein hormone family that were previously not tractable because of the absolute dependence on assembly for the biological response. Moreover, other bioactive multisubunit ligands can be engineered where the combination efficiency and specificity of heterodimers and homodimers are otherwise difficult to control.

Animals↗
PubMed1981

Improved human chorionic gonadotropin detection with carboxyl-terminal radioimmunoassay of the beta subunit on concentrated 24-hour urine in patients with testicular cancer.

The value of measuring serum levels of human chorionic gonadotropin in detecting and monitoring testicular cancer has been demonstrated convincingly. In this study the human chorionic gonadotropin was extracted by the kaolin-acetone procedure from 24-hour urine specimens and the total volume of the extract was adjusted to 15 ml. With a highly specific immunoassay system (H93) that recognizes the unique carboxyl-terminal peptide of human chorionic gonadotropin beta subunit (residue numbers 123 to 145) as described previously, the urinary human chorionic gonadotropin was measured serially in 32 patients of 15 patients with initially human chorionic gonadotropin-producing testicular tumors. These 15 patients had simultaneous measurements of serum human chorionic gonadotropin using an antiserum against the beta subunit (Sb6) and urinary human chorionic gonadotropin concentrates using H93 radioimmunoassay. The initial serum hormone levels of these 15 patients were elevated and returned to normal after therapy. However, despite this occurrence the urinary hormone levels also were elevated. The initial 5 patients with elevated urinary but normal serum human chorionic gonadotropin levels had recurrence. The use of this highly specific radioimmunoassay in measuring urinary human chorionic gonadotropin coupled with effective chemotherapeutic agents has been valuable in selecting patients in whom further therapy is warranted despite normal serum human chorionic gonadotropin and clinically undetectable tumor.

Adult↗
PubMed1976

Measurement of human chorionic gonadotropin (HCG) concentrations in paired maternal and cord sera using an assay specific for the beta subunit of HCG.

Human chorionic gonadotropin (HCG) concentrations were determined in paired maternal and cord sera using an essay specific for the beta subunit of HCG. The sera of 46 mothers and 46 infants, 24 female and 22 male, were studied. Results were compared to those obtained using a radioimmunoassay for luteinizing-hormone (LH) which cross-reacted with HCG. With either assay system, mean maternal HCG concentrations were lower when the sex of the fetus was male than when the sex of the fetus was female. Mean cord HCG concentrations of male (0.09 +/- 0.02 IU/ml) and female (0.09 +/- 0.04 IU/ml) infants were not different as determined by the beta HCG assay. In contrast, the mean cord serum concentration of HCG was significantly greater (P less than .005) in male infants (0.29 +/- 0.05 IU/ml) than in female infants (0.23 +/- 0.09 IU/ml) as determined by the cross-reacting assay. HCG concentrations were lower in both maternal and cord sera when assayed in the specific HCG system than when assayed in the cross-reacting system. There was a significant correlation (r=.9; P less than .005) between the results obtained with the two assays in both maternal and cord blood. Regardless of the assay system employed, the cord serum concentration of HCG was markedly less than the corresponding maternal serum concentration. There was no correlation between maternal and cord serum HCG concentrations with either assay. These data are in agreement with the results of previous studies employing less specific methodology which indicated that maternal serum HCG concentrations were less when the fetus was male than when it was female. They are also consistent with a placental barrier effect with regard to HCG transfer to the fetus. The difference in results obtained in cord blood with the two assay systems suggests that the newborn male infant secretes more LH and/or alpha LH subunits than the newborn female infant.

Adult↗
PubMed2003

Single-chain human chorionic gonadotropin analogs containing the determinant loop of the beta-subunit linked to the alpha-subunit.

Human chorionic gonadotropin (hCG) is a member of the family of glycoprotein hormones containing a common alpha-subunit and distinct beta-subunits that confer hormonal specificity. hCG binds to the relatively large ectodomain of the human luteinizing hormone receptor (hLHR), a member of the G protein-coupled receptor superfamily, leading to increased intracellular production of cAMP. Using protein engineering, two miniaturized versions of hCGbeta have been separately fused to the N-terminus of the alpha-subunit to give N-des[1-91]hCGbeta-alpha-C and N-des[1-91,110-114]hCGbeta-alpha-C, i.e. fusion proteins of the hCGbeta determinant loop (extended to include the complete seat belt and carboxy-terminal peptide) coupled to the alpha-subunit. Bioactivity of these single-chain gonadotropin analogs was assessed in two systems following transient transfections into HEK 293 cells and subsequent cAMP measurements. In one, each mini-beta-alpha cDNA was fused to that of hLHR and transfected into cells to create yoked miniaturized hCG-hLHR complexes; in the other, the cDNA of each single chain mini-beta-alpha was co-transfected with that of hLHR in an effort to produce non-covalent miniaturized hCG-hLHR complexes. Using yoked hCG-hLHR and hLHR as positive and negative controls respectively, expression of each mini-hCG-hLHR complex was confirmed using antibody and ligand binding assays. The two mini-hCGs led to minimal activation of hLHR, suggesting weak intrinsic activity of the mini-beta-alpha fusion proteins. These results suggest that potent agonists and antagonists will require the presence of other portions of hCGbeta in addition to the determinant loop/seat belt.

Binding Sites↗
PubMed1986

The nucleotide sequences of baboon chorionic gonadotropin beta-subunit genes have diverged from the human.

The placental glycopeptide hormone chorionic gonadotropin (CG) is involved in establishing and maintaining pregnancy. The hormone consists of two different non-covalently associated subunits termed alpha and beta. In man there are seven closely linked genes coding for beta CG-like peptides, but only three of these appear capable of expression in the placenta. The organization of beta CG-like genes in man and baboon appears to be similar. We demonstrate here that the baboon genome contains multiple copies (at least five) of beta CG-related genes, and that these genes are closely linked in the genome. Nucleotide sequence data from several beta CG cDNA clones indicates that at least two of these beta CG-related genes are expressed in the baboon placenta. Analysis of beta CG sequences from baboons and human subjects demonstrates that these genes have diverged markedly between species. In contrast, these sequences are remarkably homogeneous within their respective genomes. Gene conversion events may be responsible for retaining the high degree of identity among the various beta CG gene family members. Knowledge of beta CG sequences from baboon may lead to development of a long-term antipregnancy vaccine. The ability of CG antibodies to interfere with the maintenance of pregnancy can now be investigated within a homologous system.

Animals↗
PubMed1992

Humoral hypercalcemia associated with a dysgerminoma.

A 16-year-old girl sought medical attention at the Mayo Clinic because of a 4.5-kg weight loss, hypercalcemia, and a pelvic mass. Preoperatively, the level of the beta-subunit of human chorionic gonadotropin was 147 IU/liter. After a brief period for observation and hydration, abdominal exploration revealed a stage III dysgerminoma; total abdominal hysterectomy and bilateral salpingo-oophorectomy were performed. Within the dysgerminoma, syncytial giant cells expressed human chorionic gonadotropin-positive immunostaining in the cytoplasm. Postoperatively, the value of the beta-subunit of human chorionic gonadotropin decreased rapidly. The patient received whole-abdomen irradiation 4 weeks postoperatively, after which the level of calcium returned to normal. The patient has been free of disease for more than 7 years.

Adolescent↗
PubMed1995

Human chorionic gonadotropin in serum and neoplastic tissue from patients with bladder carcinoma.

Serum levels and tissue expression of beta subunit of human chorionic gonadotropin were determined in 25 patients with bladder carcinoma. Elevated gonadotropin levels in serum were observed in 5 (20%) patients and immunoreactive cells were found in 5 (20%) tumours. The correlation was poor between serum level and immunohistochemical gonadotropin status. Only one patient showed both elevated serum level and immunohistochemical gonadotropin expression. Our observations suggest that elevated serum levels of gonadotropin may be an indicator of poor prognosis. However, immunohistochemical expression of gonadotropin did not seem to have a similar impact on prognosis in this series.

Adult↗