PubMed Health⌕ Search

Biomedical subjects

R J Norman

Publications and source records attributed to R J Norman.

At least 19 recordsLinked to original sources
PubMed1995

Ethnic differences in insulin and glucose response to glucose between white and Indian women with polycystic ovary syndrome.

OBJECTIVE: To examine different patterns of glucose and insulin secretion in women (of both Indian and white ethnic backgrounds) with polycystic ovary syndrome (PCOS). DESIGN: A 75-g oral glucose tolerance test was performed in 11 subjects from each group. SETTING: Reproductive Medicine and Gynecological Clinics from The Queen Elizabeth Hospital, Woodville, South Australia, and King Edward the VIIIth Hospital, Durban, South Africa. PATIENTS: Couples were grouped as follows: Indian nonobese and obese PCOS, Indian nonobese and obese reference subjects, white nonobese and obese PCOS, white nonobese and obese reference subjects. MAIN OUTCOME MEASURE: Insulin and glucose in plasma after oral glucose testing. RESULTS: Indian PCOS and nonobese reference subjects had higher insulin responses than whites. The ethnic difference was less pronounced in obese women. There were no ethnic differences in glucose response. CONCLUSION: This study demonstrates that the ethnic background of subjects with PCOS needs to be considered in studies on the metabolic parameters in this condition.

Adolescent↗
PubMed1995

Cellular composition of primary cultures of human granulosa-lutein cells and the effect of cytokines on cell proliferation.

The cellular composition of cells collected from the follicular fluid obtained during the IVF procedure and cultured in vitro was examined, as well as the effects of two cytokines, interleukin-2 (IL-2) and tumour necrosis factor-alpha (TNF alpha), on the proliferation of individual cell types. After 48 h in culture, most of the cells were granulosa-lutein cells exhibiting positive staining against 3-beta-hydroxysteroid dehydrogenase (3 beta-HSD). About one-third of the total cell population stained positive with monoclonal antibodies against specific antigen sites on lymphohaemopoietic cells, including B-lymphocytes, T-lymphocytes, natural killer cells, monocytes and macrophages. During this 48-h period, IL-2 and TNF alpha significantly (P < 0.05) increased the proportion of leukocyte common antigen (LCA)-positive cells and monocytes. At the end of 144 h in culture, although LCA-positive cells and monocytes were still present, there were fewer. The main targets for the proliferative effects of IL-2 and TNF alpha in this culture system during the first 48 h are leukocytes rather than steroid-producing cells. Thus, any observed effects from the addition of cytokines in this system may be due to indirect effects of cytokine-activated leukocytes on granulosa-lutein cells.

Cell Division↗
PubMed1995

Effects of tumour necrosis factor alpha (TNF alpha) on ovulation in the rat ovary.

The effects of tumour necrosis factor alpha (TNF alpha) on ovulation rate, ovarian secretion of steroids, and on tissue concentrations of the ovulatory mediators plasminogen activator (PA) and prostaglandins were examined in rat ovaries perfused in vitro for 20 h. Unstimulated control ovaries did not ovulate whereas luteinizing hormone (LH; 100 ng mL-1) induced ovulations in all ovaries (2.6 +/- 0.7). TNF alpha (40 ng mL-1) induced ovulations in 3 of 5 ovaries (0.8 +/- 0.4). When TNF alpha was added concomitantly with LH, the LH-induced ovulation rate was increased four-fold (10.6 +/- 1.3). This effect was not seen when TNF alpha was added 5 h after LH (3.2 +/- 0.6). More progesterone was released when TNF alpha was combined with LH by comparison with LH alone. Tissue concentrations of prostaglandin F2 alpha (PGF2 alpha) and PGE were increased by the addition of TNF alpha when compared with the control group, but did not exceed those observed in the LH group, when TNF alpha was combined with LH. PA activity in the tissue was unaffected by TNF alpha and the LH-induced increase in PA activity was inhibited when TNF alpha was combined with LH. The results demonstrate that the proinflammatory cytokine TNF alpha promotes ovulations in the rat ovary.

Animals↗
PubMed1995

Immunoactive interleukin-1 beta and tumour necrosis factor-alpha in thecal, stromal and granulosa cell cultures from normal and polycystic ovaries.

Previous studies of follicular fluid from stimulated human ovaries have shown detectable amounts of immunoactive interleukin-1 (IL-1) and tumour necrosis factor-alpha (TNF). Other reports have shown the presence of IL-1 receptors, mRNA and antagonists for IL-1 in the human ovary. The aim of this study was to measure IL-1 and TNF concentrations in follicular fluid from unstimulated normal or polycystic ovaries (PCO) as well as concentrations in media conditioned by granulosa cells or thecal or stromal tissue. TNF concentrations were easily detected in follicular fluid (77 fmol/ml, range 20-95) and concentrations in PCO were similar to those in normal ovaries (70 versus 82 fmol/ml). TNF was virtually undetectable in all tissue culture media. IL-1 concentrations in all culture media were readily detected but showed no differences between different tissues or between PCO and normal ovaries. It was concluded that human ovaries readily produce immunoactive IL-1 in culture but produce less TNF despite detectable amounts of TNF in follicular fluid. There appears to be no difference between PCO and normal ovaries with respect to IL-1 and TNF.

Cells, Cultured↗
PubMed1995

Distribution of leukocyte subtypes in the sheep ovary after laser drilling.

The distribution of leukocyte subtypes in the sheep ovary following laser drilling of the ovarian capsule was examined to understand a possible mechanism by which this treatment promotes ovulation in polycystic ovarian syndrome. Ovaries were removed from sheep at different time-points following laparoscopic laser drilling and immunohistochemical detection of leukocyte subtypes, using specific monoclonal antibodies; standard histological staining was performed. Migration of leukocytes into the laser-drilled site was observed as early as 6 h after laser drilling and the total number of leukocytes in the site was found to increase up to the 12th day after surgery. In the earlier period, polymorphonuclear leukocytes were the dominant leukocyte subtypes, while macrophages and lymphocytes were the major cellular components on the 12th day and later. These results show that the tissue changes in the ovary following laser drilling are consistent with a local inflammatory reaction. The prolonged appearance of numerous macrophages following the acute inflammatory phase could lead to the secretion of cytokines and other substances suggested to be important in promoting ovulation. These data indicate that part of the effectiveness of the laser drilling in polycystic ovarian syndrome may be attributable to the secretory products of these leukocytes.

Animals↗
PubMed1995

Luteinizing hormone/chorionic gonadotropin bioactivity in the common marmoset (Callithrix jacchus) is due to a chorionic gonadotropin molecule with a structure intermediate between human chorionic gonadotropin and human luteinizing hormone.

Chorionic gonadotropin (CG), a pregnancy-specific heterodimeric hormone found in primates, is responsible for CL rescue with pregnancy maintenance. Of the primates, the human and baboon gene sequences are the only structures so far determined. In order to study the structure and function of CG in other primates, we have isolated and sequenced the coding regions for the two subunits of marmoset CG (mCG) by the reverse transcription/polymerase chain reaction method. Study of multiple clones confirmed a high degree of homology with the human sequences (88% and 80% for the alpha and beta nucleotide sequences, respectively). Marmoset CG alpha has an extra four amino acids compared to hCG alpha, whereas the mCG beta sequence has a 3-bp deletion that maintains the reading frame and C-terminal amino acid sequence. Most of the differences between hCG beta and mCG beta peptides occur in the C-terminal region, which includes the loss of two of the O-linked glycosylation consensus sequences and the presence of an N-linked glycosylation consensus sequence. When mCG alpha and beta were co-expressed in CHO cells, assembly of biologically active hormone was confirmed by induced steroid secretion by MA10 cells. Partially purified mCG beta was used to raise anti-mCG antibodies. To date, an antibody has been obtained that is capable of detecting recombinant mCG beta, recombinant mCG dimer, and mCG dimer secreted by cultured marmoset trophoblast. Marmoset CG alpha and beta were also detectable at the transcriptional level in cultured trophoblast by in situ hybridization. This suggests that the LH/CG bioactivity reported from marmoset placentae and embryos is due to a molecule with structural features common to hLH (glycosylation pattern) and hCG (CG beta C-terminal structure).

Amino Acid Sequence↗
PubMed1995

Metabolic approaches to the subclassification of polycystic ovary syndrome.

OBJECTIVES: To examine the relationship between various hormonal and metabolic variables in a large group of women with unequivocal evidence of polycystic ovarian syndrome (PCOS) to dissect out the metabolic heterogeneity of this condition. DESIGN: Cross-sectional observational study of PCOS (n = 122) and non-PCOS (n = 26) subjects. SETTING: Reproductive medicine unit in a tertiary teaching hospital. PATIENTS: Subjects with presumed PCOS were recruited from the Reproductive Medicine and Gynaecological Clinics and later confirmed as PCOS with recognized criteria. Several other subjects were identified through recruiting reference subjects. The PCOS population consisted of 122 patients. Reference subjects were recruited from partners of male factor infertility patients in the clinics and from the general population (n = 27). INTERVENTIONS: A 75 g 2-hour oral glucose tolerance test was performed on all subjects in their midluteal phase. Blood was taken at fasting and at 30, 60, 90, and 120 minutes. MAIN OUTCOME MEASURES: Age, body mass index (BMI), waist to hip ratio, levels of integrated glucose and insulin, concentrations of maximum insulin, sex hormone-binding globulin, T, triglyceride, apolipoproteins (Apo A1, B), high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol (LDLC). RESULTS: Five clusters could be identified. They are characterized as a nonobese group, a moderately obese group, and three very obese groups. The nonobese group (n = 41, BMI = 24.1) exhibited the lowest level of integrated insulin (236.4 mIU/L or microU/mL) and concentration of serum T (5.5 nmol/L). The moderately obese group had the second lowest level of integrated insulin (497.1 mIU/L) whereas the three very obese groups (n = 15, 13, and 5, respectively) had significantly higher but different levels of integrated insulin (group 3: 850.8 mIU/L; group 4: 1,131.5 mIU/L; and group 5: 1,531.9 mIU/L), triglyceride (group 3: 1.39 mmol/L; group 4: 1.76 mmol/L; and group 5: 2.78 mmol/L [1 mmol/L = 88mg/mL]), Apo B (group 3: 1.18 g/L; group 4: 1.08 g/L; and group 5: 1.55 g/L) and LDLC (group 3: 3.81 mmol/L; group 4: 3.05 mmol/L; and group 5: 5.06 mmol/L [1 mmol/L = 38.6 mg/100 mL]). CONCLUSIONS: The metabolic heterogeneity of the PCOS population is reflected at least partly in patients' levels of insulin, lipids, and lipoproteins, dependent and independent of BMI.

Adult↗
PubMed1994

Finger-prick--an alternative to venipuncture for the assessment of endocrine profiles in women.

Traditionally, there has been a reliance on venipuncture to obtain peripheral blood endocrine levels for the assessment of infertility treatment cycles. We have assessed the viability of a finger-prick capillary blood collection method to provide an alternative to venipuncture, assisting in the treatment of patients for whom venous sampling may be difficult to perform. A direct one-to-one relationship was found between the two collection methods with respect to E2, P, and LH measurement. Finger-prick blood collection is simple and easy to perform and provides a viable alternative to venipuncture. It also alleviates the stress involved with multiple attempts at venous sampling in some patients.

Blood Specimen Collection↗
PubMed1994

Characterization and relative abundance of alternatively spliced luteinizing hormone receptor messenger ribonucleic acid in the ovine ovary.

Complementary DNA (cDNA) clones encoding the LH receptor (LHR) were recently isolated from pig, rat, mouse, and human testes or ovaries. Many of the LHR cDNAs isolated from these species encoded incomplete and, therefore, possibly inactive forms of the LHR. The four major incomplete cDNAs, designated B, C, D, and E, were due to alternative splicing of the full-length cDNA, designated the A form. Northern analyses of messenger RNA (mRNA) encoding LHR in these species and in sheep revealed multiple mRNA species in ovarian tissue, but were unable to distinguish between the full-length (functional) form and the splice variants. We have used reverse transcription of mRNA, amplification via the polymerase chain reaction, and cDNA sequencing to determine which alternatively spliced mRNA species were present in ovine ovarian follicles and corpora lutea, and ribonuclease protection assays to confirm these results and determine the relative abundance of these splice variants. Ovine LHR cDNAs of the full-length A form, B form, and two novel splice forms, designated F and G, were isolated and sequenced. By using LHR cDNAs that spanned the regions of the gene in which the majority of splicing variation occurred, ribonuclease-protected fragments of different sizes were generated depending on which mRNA species (A-G) were present. It is estimated that the ratios of the steady state mRNA levels of the splice variant B form/full-length A form/G form/F form were 5-3.5:1:1:0.3. The E, C, and D forms were not detected, even when using the sensitive method of reverse transcription-polymerase chain reaction for the latter two forms. The overall level of expression of LHR mRNA was greater in corpora lutea than follicles, but the relative abundance of the splice variants was similar in follicles and corpora lutea.

Alternative Splicing↗
PubMed1993

Molecular heterogeneity of the beta-core fragment of human chorionic gonadotrophin.

We have analysed the structure and composition of the beta-core fragment of human chorionic gonadotrophin (beta C-hCG) from fresh urine specimens obtained from pregnant women and compared our findings with those previously proposed by other groups using different protocols. SDS-PAGE separation of reduced beta C-hCG demonstrated two major bands with apparent molecular weights of M(r) 8900 and M(r) 7500. The molecular weight of the agalacto beta C-hCG was estimated to be M(r) 10,218 from the amino acid analysis after high-performance liquid chromatography (HPLC) separation. Moreover, HPLC separation of its reduced and S-carboxymethylated peptides resulted in three peaks, but only two of them could be sequenced and demonstrated to be the previously reported beta 6-40 (M(r) 5000) and beta 55-92 (M(r) 5300) peptides of the beta hCG subunit. The results showed that 56-78% of beta C-hCG molecules of molecular weight M(r) 12,800 were able to bind Concanavalin A (Con A). While most were lacking all the peripheral monosaccharides and terminated in mannose, some retained other sugar residues on their antennae. Direct carbohydrate analysis showed the following molar content normalized to six mannose molecules: galactose 2.8, glucosamine 5.3, galactosamine 0.3, fucose 1.7 and sialic acid 3.0. Approximately 22-44% of the beta C-hCG molecules did not bind Con A (Con A non-reactive forms), of which 88% were totally deprived of sugar units and had an apparent molecular weight of approximately M(r) 10,000, and 12% were weakly reactive to Con A and reactive to anion exchange (negatively charged forms), being incompletely trimmed of their oligosaccharide chains. Comparison of our results with those of two other groups have indicated that the differences noted among preparations are due to either the source or the methods used to purify and characterize this fragment. In addition, our results showed significant microheterogeneity on the N-linked oligosaccharide moieties with some molecules apparently having no sugar molecules. These results have implications for the origins of beta C-hCG, suggesting secretion of some molecules without sugar chains and in other cases possible metabolism of hCG in the peripheral tissues.

Amino Acids↗
PubMed1992

Tumor necrosis factor alpha in the human ovary: presence in follicular fluid and effects on cell proliferation and prostaglandin production.

OBJECTIVE: To examine the concentration of tumor necrosis factor alpha (TNF alpha) in human follicular fluid (FF) and its effects on cultured human granulosa-lutein cells. DESIGN: The concentration of TNF alpha in FF from hyperstimulated cycles and in conditioned media from cultured granulosa-lutein cells was measured by radioimmunoassay (RIA) and bioassay using L929 cells. The effects of recombinant human TNF alpha (rTNF alpha) on proliferation and production of progesterone (P) and prostaglandin (PG, PGE2, and PGF2 alpha) by cultured human granulosa-lutein cells were assessed. SETTING: In vitro fertilization and embryo transfer (IVF-ET) program at Reproductive Medicine Unit, The Queen Elizabeth Hospital, Woodville, South Australia, Australia. PATIENTS: Twenty-five women undergoing IVF-ET for tubal factor infertility. RESULTS: The concentration of immunoreactive TNF alpha in FF was 0.36 +/- 0.02 microgram/L, and there were no significant correlations between levels of TNF alpha and steroids or FF volume. Bioactivity for TNF alpha was considerably less. Immunoreactive or bioactive TNF alpha was not detected in conditioned media from granulosa-lutein cell culture. Recombinant human TNF alpha dose-dependently stimulated proliferation of cultured granulosa-lutein cells as measured by incorporation of 3H-thymidine, but in contrast to earlier reports, we were not able to demonstrate any effect of rTNF alpha on basal or human chorionic gonadotropin-stimulated P accumulation during culture periods of up to 72 hours. The accumulation of both PGE2 and PGF2 alpha was dose-dependently increased by rTNF alpha during a 48-hour incubation period. Time course studies revealed that maximal levels of both PGE2 and PGF2 alpha were reached within 12 hours of culture. CONCLUSION: Immunoreactive and bioactive TNF alpha is present in FF. Tumor necrosis factor alpha may have a physiological role in stimulating proliferation of follicular cells and PG production at the time of ovulation and formation of the corpus luteum.

Cell Division↗
PubMed1992

Concentrations of immunoreactive interleukin-1 and interleukin-2 in human preovulatory follicular fluid.

The presence of immunoreactive interleukin-1 (IL-1) and interleukin-2 (IL-2) in human follicular fluid obtained at the time of oocyte collection for in-vitro fertilization was ascertained by radioimmunoassay. In group I (20 fluids from 20 patients), the concentrations of IL-1 were 0.9 +/- 0.06 and 1.9 +/- 0.04 (mean +/- SEM) fmol/l in follicular fluid and plasma respectively. A positive correlation existed between IL-1 levels in follicular fluid and plasma (r = 0.56, P less than 0.01). Concentrations of IL-2 were 3.5 +/- 0.2 and 6.1 +/- 0.3 fmol/l in follicular fluid and plasma respectively. A positive correlation of IL-2 levels was also found between follicular fluid and plasma (r = 0.65, P less than 0.01). There was no association between IL-1, IL-2 and steroid levels, regardless of whether they were compared in follicular fluid or plasma. Group II was composed of a series of fluids (two to seven samples for each of seven patients) in which the follicular concentrations of IL-1 and IL-2 did not show a positive correlation with the volume of follicular fluid or the concentrations of follicular fluid steroids. It is concluded that human preovulatory follicular fluid contains immunoreactive IL-1 and IL-2. The role of IL-1 and IL-2 in ovarian physiology remains to be determined.

Estradiol↗
PubMed1992

Distribution of leukocyte subpopulations in the human corpus luteum.

Cytokines, as secreted products of leukocytes, have roles in many organs of the body via paracrine or autocrine mechanisms. In the present study, we demonstrate by immunocytochemistry the leukocytes present in the human corpus luteum in order to investigate further the relationship between leukocytes, cytokines and corpus luteum function. Ten intact corpora lutea were collected from female patients who had no apparent ovarian disease. The mean age of these patients was 37 years (range 23-55 years). Frozen and paraffin sections were subjected to analysis using monoclonal antibodies which were specific to leukocyte marker antigens. The results showed that there are macrophages, cells positive for leukocyte common antigen (LCA), T lymphocytes including T helper/inducer (T4) cells, T cytotoxic/suppressor (T8) cells and activated T (Ta) cells (interleukin-2 receptor-positive cells), monocytes and natural killer (NK) cells but not B lymphocytes present in the human corpus luteum. The distribution of the leukocytes present in the different parts of the corpus luteum was found to be in the order: theca-luteal area greater than loose connective tissue area greater than granulosa-luteal area. Macrophages and T lymphocyte subsets comprised the main components of the total leukocytes in the human corpus luteum. Ta cells were only localized in the loose connective tissue of the corpus luteum. In most cases, macrophages, LCA cells and T4 cells tended to be situated in a single cell layer on the edge of the theca-luteal area and surrounding the granulosa-luteal area. These results suggest that the leukocytes may act to a greater extent in the theca-luteal area than in the granulosa-luteal area.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Comparison of specific immunoassays for detection of the beta-core human chorionic gonadotrophin fragment in body fluids.

We have validated two new methods, one radioimmunoassay (RIA) and one immunoradiometric assay (IRMA), for the detection of beta-core hCG fragment (beta C-hCG) in body fluids. In addition, we have compared their performance with two other assays designed for beta C-hCG quantification. The RIA uses a rabbit polyclonal antibody raised against pure beta C-hCG which has a high affinity constant, is sensitive to 5 pmol/l, and has significant cross-reaction only with the free beta LH subunit. The IRMA, designed in a liquid phase, uses the same polyclonal antibody associated with a 125I-labelled mouse monoclonal antibody (32H2) raised against beta hCG, is sensitive to 1.5 pmol/l, and does not cross-react significantly with any related glycoprotein. Comparison between these two assays and two others previously published was made by measuring beta C-hCG in urine from healthy pregnant women (n = 47) and gave correlation coefficients higher than r = 0.960 with any combination. Analysis of beta C-hCG in urine of non-pregnant subjects (n = 238) showed measurable beta C-hCG in 8.8% (levels ranged from 5 to 34 pmol/l) with the IRMA and 88.3% with the RIA (n = 30; ranging from 28.4 to 228 pmol/l) (P = 0.05). We concluded that, despite different affinities of the antibody involved and different cross-reactivities with related glycoproteins, the four assays we examined may be equally employed to detect beta C-hCG in pregnancy urine. However, the IRMA appears to be more appropriate for beta C-hCG analysis in non-pregnant individuals, specifically in postmenopausal women because of the high cross-reactivity of the RIA with free beta LH or beta fragments of other glycoproteins. These studies have significance for our understanding of the physiology of beta C-hCG in cancer, pregnancy and after the menopause.

Antibodies↗
PubMed1992

Distribution of the beta-core human chorionic gonadotrophin fragment in human body fluids.

The origins of a fragment of the human chorionic gonadotrophin (hCG) molecule, beta-core (beta C-hCG) were studied by analysis of beta C-hCG concentrations in biological fluids. In addition, the ability of the placenta to produce the fragment and the metabolism of hCG to beta C-hCG by human granulosa cells was determined in tissue culture. Finally the conversion of exogenous hCG to beta C-hCG was studied in vivo. The fragment was present in pregnancy urine as well as that from premenopausal and postmenopausal subjects. The highest concentrations were found in pregnant women. Ratios of beta C-hCG to intact hCG were higher in pregnancy urine when radioimmunoassay (RIA) was used compared with immunoradiometric assay (IRMA) (0.67 and 0.37 respectively). Concentrations of beta C-hCG were higher in postmenopausal urine than in premenopausal specimens. A significant amount of a high molecular weight beta C-hCG immunoreactive material was found in serum samples after size separation, and the molar ratio of beta C-hCG/hCG was estimated as 0.019. Amniotic fluid also contained small quantities of two forms of immunoreactive beta C-hCG and the ratio of 0.01 for authentic beta C-hCG/hCG increased to 0.026 when the high molecular weight form was considered. Cultured trophoblastic tissue released material with beta C-hCG immunoreactivity in the medium and chromatographic separation revealed that the majority of this material was of higher molecular weight compared with the authentic beta C-hCG form. beta C-hCG was the principal glycoprotein found in follicular fluid after hyperstimulated folliculogenesis and intramuscular injection of 5000 IU hCG. We also demonstrated that 26% of follicular fluid samples (n = 50) were positive for beta C-hCG; levels ranged from 5.2 to 23.0 pmol/l (13.1 +/- 5.7); S.D.) when a specific IRMA was used. The RIA could detect beta C-hCG in 48 samples (96%), levels ranging from 7.0 to 28.5 pmol/l (19.4 +/- 5.2). Moreover, granulosa cells cultured in the presence of hCG were able to degrade the intact molecule to both high molecular weight and authentic immunoreactive forms of beta C-hCG. After gel filtration, material of molecular weight over a wide range and immunoreactive for beta C-hCG was present in human seminal plasma. Assaying 74 samples of this fluid by IRMA, beta C-hCG was detected in 42 (56.7%), levels ranging between 5.5 and 59.5 pmol/l (24.9 +/- 15.2).(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1992

Urinary concentrations of beta core fragment of hCG throughout pregnancy.

OBJECTIVE: We sought to determine a reference range for urinary immunoreactive beta core fragment of hCG (beta C-hCG) in pregnancy, the ratio between beta C-hCG and intact hCG, and the earliest detectable rise of beta C-hCG in urine. METHODS: Urine was obtained from 741 pregnant women between 6-41 weeks' gestation, as well as from women undergoing donor insemination with timed ovulation peaks. RESULTS: The beta core fragment of hCG reached a maximum between 8-15 weeks, with a decrease between 20-29 weeks. The molar ratio of beta C-hCG to intact hCG was always greater than 1. CONCLUSION: In pregnancy, beta C-hCG concentrations increase in the urine in parallel to intact hCG but at a higher molar ratio, suggesting either placental production of beta C-hCG or enhanced metabolism of hCG to beta C-hCG in peripheral organs.

Chorionic Gonadotropin↗
PubMed1992

Simple quantitative measurement of serum choriogonadotropin compared with immunoradiometric, immunoenzymometric, and chemiluminescent assays.

We evaluated a new simplified quantitative method (Tandem Icon QSR; Hybritech) for choriogonadotropin (hCG), which could theoretically be performed in a ward or with outpatients. The method was compared with immunoradiometric (Bioclone Australia), chemiluminescent (Amerlite; Amersham), and immunoenzymometric assays (Stratus; Dade). We analyzed by each of the methods 104 serum samples from pregnant and nonpregnant patients. For quantitative hCG values indicative of pregnancy (greater than 25 int. units/L), excellent correlation was observed between the Tandem Icon method and the other standard laboratory assays (r = 0.995, 0.990, and 0.992, respectively). Occasional problems arose because of the instability of Tandem Icon QSR reagents at room temperature but this was resolved by storing the reagents at 4 degrees C. We conclude that this simplified quantitative method for hCG is reliable and suitable for use outside of the routine immunoassay laboratory.

Chorionic Gonadotropin↗