Biomedical subjects

W R Robertson

Publications and source records attributed to W R Robertson.

At least 37 records · Page 2Linked to original sources

PubMed1996

Internal carbohydrate complexity of the oligosaccharide chains of recombinant human follicle stimulating hormone (Puregon, Org 32489): a comparison with Metrodin and Metrodin-HP.

Glycoforms of recombinant human follicle stimulating hormone (rhFSH) (Org 32489, Puregon) were characterized using concanavalin A lectin affinity chromatography to reveal information about the internal carbohydrate complexity (extent of carbohydrate side-chain branching) of the preparations. The rhFSH glycoforms were measured by radioimmunoassay and a two-site immunoradiometric assay and compared with those in two urinary preparations (Metrodin and Metrodin-HP) used in assisted reproduction programmes and a urinary FSH international standard 70/45 (uFSH IS 70/45). Similar data were obtained with both assays; rhFSH had 6% complex internal carbohydrate structures compared with 22-27% for Metrodin, Metrodin-HP and uFSH. The proportion of simple carbohydrate structures was also different, with rhFSH having 18.5 compared with 4.5-9.3% for Metrodin, Metrodin-HP and uFSH. A linear relationship was observed between the percentage glycoforms with an isoelectric point (pl) < 4 and the log percentage simple forms (logarithmic regression; r = 0.93) indicating a direct relationship between carbohydrate complexity and charge heterogeneity. In summary, rhFSH contains fewer complex forms and an increased proportion of simple carbohydrate structures in comparison with Metrodin, Metrodin-HP and IS 70/45.

Carbohydrates↗

PubMed1996

Oestradiol and immunoreactive inhibin-like secretory patterns following controlled ovarian hyperstimulation with urinary (Metrodin) or recombinant follicle stimulating hormone (Puregon).

Inhibin (and its alpha-subunit) may be of particular value as a marker for follicular development in in-vitro fertilization (IVF) in comparison with the classic follicle stimulating hormone (FSH)-dependent marker oestradiol in patients following pituitary desensitization and treatment with recombinant FSH (rFSH). This preparation lacks luteinizing hormone (LH), which is essential for thecal cell androgen secretion and thus oestradiol production. Our study has assessed oestradiol and immunoreactive inhibin-like secretion following ovarian stimulation with rFSH or a purified urinary FSH preparation (Metrodin) (uFSH). A randomized, assessor-blind study was initiated using patients receiving a single treatment cycle of IVF (using fresh embryos) following pituitary desensitization with intranasal buserelin (500 microg daily) and the i.m. injection of either rFSH (n = 38) or uFSH (n = 17). Ovarian ultrasound examinations were performed and bloods (10 ml) collected prior to FSH treatment and every 1-2 days until ovulation induction with human chorionic gonadotrophin. LH and FSH concentrations were measured by an immunoradiometric assay, and inhibin-like immunoreactivity by a radioimmunoassay and an enzyme-linked immunosorbent assay, both with alpha-subunit specificity. Oestradiol concentration was measured with a coated tube radioimmunoassay. Following desensitization, basal LH, FSH and oestradiol concentrations were measured, as was that of immunoreactive inhibin. Following treatment with either rFSH or uFSH, LH concentrations remained low while FSH concentrations rose to a plateau of 5.6-6.7 IU/l in both groups. In contrast, the concentration of oestradiol was higher (P < 0.05) with rFSH than with uFSH in the last four days of treatment, a pattern that was repeated for inhibin-like immunoreactivity. The change in oestradiol and inhibin concentrations during treatment was approximately 2-fold higher with rFSH. The total number of follicles obtained with rFSH was similar to that with uFSH. However, the number of follicles with a diameter of >/= 15 mm was higher the rFSH group, and there was a concomitant increase in the number of oocytes recovered. Oestradiol concentration and inhibin-like immunoreactivity (determined by either method) were associated with total follicle number and number of follicles >/= 15 mm in diameter, as well as with each other (P < 0.001). When ovarian hormone output was normalized per follicle produced, oestradiol output was higher for rFSH than for uFSH P = 0.04). Inhibin output was clearly higher using rFSH than uFSH. There were seven pregnancies (one miscarriage) with rFSH and two with uFSH. Despite similar concentrations od FSH in patients, rFSH (Puregon) appears to be more potent in vitro in terms of follicular number, ovarian hormone secretion (both concentration and output/follicle) and oocyte recovery. In both groups, LH concentrations of approximately 1.3 IU/l were sufficient to support oestradiol secretion similar to that normally found in IVF programmes using human menopausal gonadotrophin preparations containing large amounts of LH. Despite known problems of specificity with the assays od inhibin, its measurement was of similar value to oestradiol as a marker of follicular development.

Adult↗

PubMed1996

A search for immunoglobulins inhibiting gonadal cell steroidogenesis in premature ovarian failure.

Premature ovarian failure (POF) may be caused by the action of circulating gonadotrophin receptor-blocking antibodies. Luteinizing hormone (LH)-stimulated testosterone production from mouse Leydig cells and follicle stimulating hormone (FSH)-stimulated oestradiol production from immature rat Sertoli cells were therefore studied in the presence of protein-G purified immunoglobulin G (IgG) samples from control subjects (n = 9), infertile women with elevated early follicular phase FSH levels but otherwise normal menstrual cycles (n = 10), and patients with POF (n = 10) or Graves' disease (n = 10). A saturating and subsaturating (78% for LH; 60% for FSH) dose of each hormone was chosen for study. A commercial preparation of human IgG (Sigma IgG, 0.75 mg/ml) employed as negative control had no effect on basal or gonadotrophin-stimulated steroidogenesis. In its presence, saturating doses of LH (2 IU/l) and FSH (20 IU/l) gave rise to 11.2 +/- 0.8 (n = 7) and 25.1 +/- 5.8 (n = 8) fold increases in steroid secretion. IgG (0.75 mg/ml) had no effect in the four groups on LH-stimulated testosterone outputs using a saturating (2 IU/l) or subsaturating (1 IU/l) dose of hormone. For example, LH (2 IU/l)-stimulated testosterone production was 94% (83-96 median; interquartile range) and 88% (81-99) of the Sigma IgG control for control and POF groups respectively. However, four out of nine IgG samples from the normal subjects (mean +/- SEM = 86 +/- 6%), two out of 10 of the high FSH group (77 +/- 4%), five out of 10 with Graves' disease (86 +/- 3%) and six out of 10 with POF (76 +/- 6%) gave rise to LH (2 IU/l)-stimulated testosterone outputs which were lower (P < 0.05) than that of Sigma IgG control. Using the identical set of patients and an IgG concentration of 0.25 mg/ml, the FSH-stimulated oestradiol outputs of the four groups were similar when using either the saturating (20 IU/l) or subsaturating (5 IU/l) dose of the hormone. Thus, the percentage of FSH (20 IU/l)-stimulated oestradiol production of the Sigma IgG control was 81 (66-89 median, interquartile range) and 50 (38-84) for control and POF groups respectively. However, once again individual patients had inhibitory IgGs such that four out of nine (controls), three out of 10 (high FSH group), four out of 10 (Graves' disease) and six out of 10 (POF patients) inhibited (P < 0.05) FSH (20 IU/l)-stimulated oestradiol secretion by 52 +/- 9 (mean +/- SEM), 44 +/- 7, 52 +/- 6 and 41 +/- 6% respectively. Of the patients with inhibitory IgGs the extent of inhibition of gonadotrophin-stimulated steroid secretion was similar between the groups. In conclusion, there is little evidence to suggest that immunoglobulins blocking gonadotrophin receptors are a mechanism for POF in a large proportion of women suffering from this condition.

Adult↗

PubMed1996

Differences in serum luteinizing hormone measurements by immunoradiometric assay induced by kinetic manipulation of assay conditions are dependent on the endocrine milieu of serum.

Divergent estimates for luteinizing hormone (LH) in individual serum samples may be given by different immunoassays. In order to investigate this phenomenom further, we have studied the effect of differences in assay kinetics within the same immunoradiometric assay (IRMA) configuration on LH measurement in sera from different endocrine states. Three pairs of monoclonal/polyclonal two-site IRMA systems for LH were developed from three LH monoclonal antibodies and a common polyclonal anti-human chorionic gonadotrophin. For IRMA systems a short and long assay, which were different only with respect to the incubation time (1/2 h and overnight respectively), of the labelled monoclonal first antibody were performed. The IRMAs were all standardized against the LH international reference preparation 68/40. LH concentrations were measured by all the IRMAs in sera obtained from normal men (n = 11) and from women with polycystic ovarian syndrome (PCO; n = 13). In normal men, there were no differences in LH estimates between the short and the long assays of the three IRMA systems, and the ratios of long to short assays were similar for all the systems. However, in PCO there were significant differences between short and long assays and the ratios of long to short assays were different for the IRMA systems. These results indicate that kinetic differences between IRMAs of the same antibody configuration can be associated with differences in measured LH concentrations, depending on the endocrine status of the sera studied. As LH glycoform patterns are known to differ between normal men and PCO, the observed changes in LH estimates may be due to the different glycoform composition.

Adult↗

PubMed1995

In-vitro biopotency and glycoform distribution of recombinant human follicle stimulating hormone (Org 32489), Metrodin and Metrodin-HP.

In this study the in-vitro biopotency and glycoform distribution of human recombinant follicle stimulating hormone (FSH, Org 32489) has been assessed. The biopotency of recombinant FSH was studied using animal (rat Sertoli) and human (granulosa-lutein) cell models. Recombinant FSH, as measured in the rat Sertoli cell assay, was more potent than the urinary preparations Metrodin, Metrodin-HP and IS 70/45 with half maximal stimulation (ED50; mean +/- SEM, n > 3) occurring at 2.2 +/- 0.5 IU/I (recombinant FSH), 4.7 +/- 1.1 IU/I (Metrodin), 13.2 +/- 0.7 IU/I (Metrodin-HP) and 6.4 +/- 0.3 IU/I (IS 70/45); the pituitary preparation IRP 83/575 had an ED50 of 10.4 +/- 0.1 IU/I. Using human granulosa-lutein cells, cultured for up to 4 days in the absence of exogenous steroid precursors, recombinant FSH was either without effect (three out of five patients) or inhibited both oestradiol and progesterone secretion. FSH (83/575) was without effect on oestradiol with preparations from any of the patients but slightly stimulated (134 +/- 8%; mean +/- SEM, P < 0.05) progesterone production at the highest dose (80 IU/I). The distribution of FSH isoforms, assessed by polyclonal radioimmunoassay, following chromatofocusing over the ranges pH < 3.5 and pH 3.5-7.0 respectively was recombinant FSH, 12.4 and 87.6%; Metrodin, 19.8 and 80.2%; Metrodin-HP, 50.2 and 49.8%; IS 70/45, 15.0 and 85.0%; IS 83/575, 70.9 and 29.1%. All glycoforms were pI < 7.0 for the five preparations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Variability in the immunoreactive and bioactive follicle stimulating hormone content of human urinary menopausal gonadotrophin preparations.

The within- and between-batch variation in the immunoreactive and in-vitro bioactive FSH content of Pergonal, Metrodin and Metrodin-HP was investigated. Three batches of Pergonal and Metrodin, consisting of three ampoules in each batch, and three batches of Metrodin-HP, consisting of between one and three ampoules per batch, were selected at random. The follicle stimulating hormone (FSH) content of Pergonal, Metrodin and Metrodin-HP was determined by radioimmunoassay (R-FSH) and the in-vitro rat Sertoli cell bioassay (B-FSH) using the international urinary standard 70/45. The variability in the FSH content of the preparations was evaluated within and between batches by analysis of variance. Within-batch variability of B-FSH was not observed in Pergonal or Metrodin-HP but was seen in two batches of Metrodin in which the potency varied by up to 2.4 fold (P = 0.03). The between-batch R-FSH potencies of Pergonal (P1-P3) varied, with P2 (59.8 +/- 0.6) and P3 (61.7 +/- 0.9) being higher than P1 (47.1 +/- 1.5 mean +/- SEM IU/ampoule, P < 0.01). A similar pattern of variability was observed for B-FSH. For Metrodin, each of the batch R-FSH potencies was dissimilar (P < 0.02), with estimates ranging from 34.9 +/- 1.2 to 64.3 +/- 1.8 IU/ampoule. Furthermore, the extensive within-batch B-FSH variation from two batches confounded any meaningful comparison of between-batch variability. For Metrodin-HP, there was no between-batch B-FSH variation (29.0 +/- 6.1 to 33.0 +/- 0.3 IU/ampoule) and the R-FSH content was also well controlled (41.2 +/- 0.5 to 46.9 +/- 1.1 IU/ampoule).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1995

Age related changes in the pituitary-testicular axis in normal men; lower serum testosterone results from decreased bioactive LH drive.

OBJECTIVE: The mechanism underlying the slight hypoandrogenism associated with normal ageing remains unclear. We have therefore examined age related changes in the activity of the pituitary-testicular axis in healthy normal males. DESIGN: Random blood samples were obtained from 219 normal men whose ages ranged from 20 to 79 years. At the time of the study, none of the men had received treatment or had ever had any endocrine dysfunction diagnosed. MEASUREMENTS: Luteinizing hormone was measured in the subjects' plasma using a commercially available immunoradiometric assay (IRMA, Serono Maiaclone) and a fully validated in-vitro bioassay. Testosterone and FSH were measured using standard radioimmunoassays (RIA) whilst sex hormones binding globulin was assayed by an IRMA. RESULTS: Levels of total testosterone (total-T) and bioactive LH fell with age (r = -0.231 and -0.189 respectively) by 5.9 nmol/l and 2.3 IU/l respectively between grouped patients aged 20-39 years (Group A) and 60-79 years (Group C). In contrast, immunoreactive LH remained unchanged. The LH B:I ratio also fell with age (P < 0.0001) being 5.0 +/- 0.3 (group A) and 3.3 +/- 0.2 (group C), representing a fall of 33%. Since immunoreactivity remained constant, this fall primarily represented the decline in LH bioactivity. Bioactive, but not immunoreactive LH correlated to total-T (P = 0.009, n = 209) and the total-T:LH ratios fell by over 30% between groups A and C using the IRMA, but remained unchanged by bioassay. CONCLUSIONS: There is an underlying decline in both total-testosterone and free-testosterone index, and bioactive LH levels with advancing age, suggestive of a hypothalamo-pituitary defect which leads to lower bioactive LH levels which in turn are responsible for the diminished gonadal steroidogenesis. Elucidation of the mechanism underlying this slight decline in hypothalamopituitary testicular activity is complicated by differences between the data obtained by immunoassay or bioassay.

Adult↗

PubMed1995

Degree of activation of the pituitary-testicular axis in early pubertal boys with constitutional delay of growth and puberty determines the growth response to treatment with testosterone or oxandrolone.

Early pubertal boys (testicular volume, 4-6 mL) with constitutionally delayed growth and puberty were randomized to 3 months of treatment after a baseline 12-h overnight hormone profile: group 1 (n = 5), daily placebo; group 2 (n = 5), 2.5 mg oxandrolone daily; or group 3 (n = 6), 50-mg testosterone monthly im injections. LH and GH profiles (15-min samples) were analyzed by peak detection (Pulsar), Fourier transformation, and autocorrelation. FSH and testosterone levels were measured hourly, and insulin, sex hormone-binding globulin, insulin-like growth factor-I, and insulin-like growth factor-binding protein-3 levels were determined at 0800 h. Multiple regression was used to analyze the response to treatment (growth) with respect to baseline features. Endocrine variability was marked. Profiles ranged from unreactive to well established LH pulsatility and adult testosterone levels. The areas under the curve (AUC) for LH, FSH, and testosterone ranged 10-fold (4.4-46.3 IU/L.h), 8-fold (7.9-63.4 IU/L.h), and 45-fold (3.6-161.7 nmol/L.h), respectively. The growth response was individually varied, but significantly increased 0-6 months in the active treatment groups. Age, testicular volume, and LH AUC interacted significantly (r2 = 0.95; P < 0.05). Allowance for these produced a highly significant treatment effect (P = 0.006). Age, testicular volume, LH AUC, and testosterone AUC, but not treatment, significantly increased growth by 0-12 months (r2 = 0.88; P < 0.05). We demonstrate a spectrum of activation of the reproductive axis despite tight clinical staging. This, and not GH status at treatment commencement, influenced the growth response.

Adolescent↗

PubMed1995

Immunometric assays of luteinizing hormone (LH): differences in recognition of plasma LH by anti-intact and beta-subunit-specific antibodies in various physiological and pathophysiological situations.

Restricted immunoreactivity of plasma luteinizing hormone (LH) has been described in some subjects when assayed with certain methods involving antibodies against intact LH. We have compared the performance of the Amerlite LH-30 (A) and Delfia LHSpec (D) assays (which include anti-intact and beta-specific antibodies, respectively) in normal and pathological conditions. As shown previously, results of the two systems were highly correlated with each other and, as we show here, with those of a bioassay. We found eight outliers (results outside the 95% confidence interval of the regression) among 427 samples studied from 121 subjects. Of the outliers, five had Delfia results in a range (< 1 IU/L) that was associated with poor assay precision for that assay, and the ratios of their values by both methods (A:D ratios) were very low. This ratio was affected by endocrine status, e.g., was lower in postmenopausal women than in premenopausal controls, and varied intraindividually within the same menstrual cycle. The restricted immunoreactivity described previously for assays involving anti-intact LH antibodies may, in part, reflect these differences, which, in turn, may reflect the presence of isoforms (e.g., glycoforms) that are differentially recognized by assays that have different antibody configurations.

Antibodies↗

PubMed1995

A critique of 'at risk' pressure sore assessment tools.

This paper critiques pressure sore risk assessment tools. No attempt is made to describe individual tools in detail as this literature is available elsewhere. The economic case for risk assessment is presented along with the criteria for an effective risk assessment instrument. Reliability and validity studies are reviewed in relation to three risk assessment tools: Norton, Waterlow and Braden. Finally a number of issues related to threshold scores, research design and the need to view pressure sores as a clinical problem rather than a nursing problem are discussed.

Humans↗

PubMed1994

Immunoreactive and bioactive luteinizing hormone in pubertal patients with chronic renal failure. Cooperative Study Group on Pubertal Development in Chronic Renal Failure.

Disturbed pulsatile LH secretion has been suggested to play a role in the etiology of delayed puberty and disturbed reproductive function in chronic renal failure (CRF), but interpretation of gonadotropin secretion from plasma concentration measurements is confounded by alterations in hormone metabolic clearance. To simultaneously investigate LH secretion and clearance in children, we performed multiple-parameter deconvolution analysis of 11-hour over-night serum LH concentration-time series of bioactive (bio-LH) and immunoreactive (i-LH) hormone in 36 pubertal patients (18 boys) with various degrees of CRF and 10 healthy controls matched for sex and pubertal stage. Twelve patients received conservative treatment for advanced but compensated CRF, 12 were treated by dialysis, and 12 were studied after successful renal transplantation. We observed that: (1) the mean (+/- SE) plasma half-lives of bio-LH and i-LH were increased in the dialysis group (155 +/- 47 and 201 +/- 31 min) and in the patients on conservative treatment (148 +/- 45 and 135 +/- 70 min) compared to controls (59 +/- 28 and 63 +/- 21 min; all P < 0.05). The plasma half-life of bio-LH in patients on conservative treatment or after renal transplantation was inversely correlated with glomerular filtration rate (GFR) (r = -0.70; P < 0.0001). (2) Pulsatile bio-LH production rate was independently affected by pubertal stage (P = 0.018) and treatment status (P = 0.017), increasing across pubertal stages and being significantly lower in dialysis patients (20 +/- 4 IU/liter * 11 hr) and patients on conservative treatment (28 +/- 9) than in controls (43 +/- 9; all P < 0.05). In patients on conservative treatment or after transplantation, a significant positive correlation between pulsatile bio-LH production rate was observed (r = 0.53; P < 0.008). Pulsatile i-LH secretion rate was significantly reduced only in dialysis patients (15 +/- 34 vs. 46 +/- 18; P < 0.05). (3) The reduction of pulsatile i-LH and/or bio-LH production rates was attributable to a halving of the LH mass secreted per burst in patients on conservative (bio-LH: 4.9 +/- 1.9 IU/liter) and dialysis treatment (bio-LH: 3.2 +/- 0.7, i-LH: 2.4 +/- 0.6 IU/liter) versus controls (bio-LH: 6.9 +/- 1.3, i-LH: 5.4 +/- 2.1 IU/liter), whereas the LH pulse frequency was not different between controls and treatment groups.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

PubMed1994

Exogenous steroids and the control of oestradiol secretion by human granulosa-lutein cells by follicle stimulating hormone and insulin-like growth factor-I.

This study first examined the relative activities of 17 alpha-hydroxylase, 17,20-lyase and aromatase in human granulosa-lutein cells by challenging the cells with steroid precursors in the oestradiol biosynthetic pathway. When cells from four patients were challenged with precursor steroids on the pathway to oestrogen synthesis (pregnenolone, 17 alpha-hydroxypregnenolone, progesterone, 17 alpha-hydroxyprogesterone and androstenedione at 5 x 10(-6) M), oestradiol (nmol/l) outputs after 1 day of culture were (median, interquartile range) as follows: 4.1 (2.1-8.8; pregnenolone), 3.1 (1.7-6.0; progesterone), 12.5 (6.9-18.1; 17 alpha-hydroxypregnenolone), 8.2 (4.1-16.7; 17 alpha-hydroxyprogesterone) and 251 (140-819; androstenedione). No further increases were seen when the steroid concentration was increased to 1 x 10(-5) M. Basal oestradiol secretion was 3.5 (1.6-8.2) nmol/l. We conclude that the conversion of pregnenolone/progesterone to oestradiol by granulosa-lutein cells is rate limited by 17 alpha-hydroxylase activity but that these cells are capable of oestradiol secretion (in the nmol/l range) in the absence of androstenedione. In the second part of this study we examined the control of granulosa-lutein oestradiol secretion by follicle stimulating hormone (FSH) and insulin-like growth factor-I (IGF-I) in the presence and absence of exogenous androstenedione (10(-6) M). Cells were cultured for up to 6 days and basal oestradiol (nmol/l) fell dramatically over this period both in the presence and absence of androtenedione, e.g. from 339 (223-419) (median and interquartile range, cells from five patients cultured in the presence of androstenedion) after 2 days to 14 (7-59) after 6 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldehyde-Lyases↗

PubMed1994

Accumulation of human chorionic gonadotrophin in the serum of patients during in-vitro fertilization treatment cycles with Pergonal.

We examined the possible contribution of human chorionic gonadotrophin (HCG) in Pergonal to the serum luteinizing hormone (LH)-like bioactivity in 10 patients (median age 32 years, range 28-38) with tubal infertility who were undergoing in-vitro fertilization (IVF), together with 19 controls (median age 30 years, range 21-43). IVF patients were treated with clomiphene (50 mg twice daily) over days 2-6 and Pergonal (150 IU i.m.) daily from day 5 until at least day 10. Serum LH was measured by fluoro-immunometric assay (I-LH) and in-vitro Leydig cell bioassay (B-LH). Serum HCG was measured by fluoro-immunometric assay. The data were analysed by paired two-tailed t-test, following logarithmic transformation. From days 1-5, there was an increase in serum B-LH (mean, 95% confidence intervals given in parentheses) from 8.3 (6.8, 10.2) IU/l to 11.7 (9.8, 13.9) IU/l [P = 0.004], and in serum I-LH from 4.5 (3.7, 5.4) IU/l to 5.4 (4.6, 6.3) IU/l [P = 0.002]. From days 5-8, there was a rise in B-LH to 16.6 (12.6, 21.9) IU/l [P = 0.023]. The rise in I-LH to 6.3 (5.1, 7.8) IU/l [P = 0.081] failed to reach significance. Furthermore, serum HCG was < 0.75 IU/l until after Pergonal was administered on day 5, then rose to a plateau on day 8 at 1.2 (0.8, 1.6) IU/l. Serum HCG in the controls remained < 0.75 IU/l throughout.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Serum concentrations of dimeric inhibin during the spontaneous human menstrual cycle and after treatment with exogenous gonadotrophin.

A recently described two-site enzyme immunoassay incorporating a pre-assay oxidation step was validated and used to measure serum concentrations of dimeric inhibin in five normally cycling women and in 13 women undergoing gonadotrophin therapy. Recombinant human inhibin A (standard) gave an assay response curve which was parallel to those for human serum samples and recovery of exogenous inhibin added to serum samples before assay was quantitative (109 +/- 8%, n = 11). During the normal menstrual cycle dimeric inhibin concentration increased from 9.0 +/- 2.0 pg/ml during the early follicular phase to reach a mid-cycle peak of 55.3 +/- 11.1 pg/ml coincident with the pre-ovulatory gonadotrophin surge. After falling to 27.9 +/- 5.7 pg/ml 1 day after the luteinizing hormone surge, inhibin then rose in parallel with serum progesterone to reach a peak value of 115.6 +/- 19.3 pg/ml during the mid-luteal phase, before falling to 14.1 +/- 4.9 pg/ml by the onset of next menses. During the follicular phase, dimeric inhibin concentrations were closely correlated with those of serum oestradiol (r = 0.69; P < 0.001), whereas during the luteal phase they were most closely correlated with serum progesterone concentrations (r = 0.73; P < 0.001). Daily treatment with human menopausal gonadotrophin promoted a progressive increase in serum dimeric inhibin concentration which increased approximately 20-fold in 6 days. In the same period total alpha-inhibin (measured by radioimmunoassay) increased approximately 5-fold, while serum oestradiol increased approximately 30-fold.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Less acidic forms of luteinizing hormone are associated with lower testosterone secretion in men on haemodialysis treatment.

OBJECTIVE: Men with chronic renal failure treated by haemodialysis have raised levels of bioactive LH (B-LH) and immunoreactive LH (I-LH) but reduced B-LH:I-LH (B:I) ratio and testosterone (T) secretion. This study investigated the LH isoform distribution in serum from normal adult males and males on regular haemodialysis treatment. DESIGN: Four blood samples (2 ml) were obtained at 15-minute intervals from a group of men on regular haemodialysis treatment. These samples were part of a larger pulse profile series and showed no evidence of LH pulsatility. The serum was pooled for each individual patient. Blood (10 ml) was also drawn randomly from healthy male volunteers. The sera were chromatofocused on a 4-ml mono-P column attached to a fast performance liquid chromatography system. This procedure separates the LH isoforms according to their isoelectric point. The pH gradient was between pH 7 and pH 4. PATIENTS: The five men with chronic renal failure were aged between 18 and 40 years and had been on haemodialysis for a mean of 10 months (5-20). They were sampled the night prior to a dialysis session. The five normal healthy volunteers had never had any endocrine disorder diagnosed. MEASUREMENTS: An immunoradiometric assay and a commercially available (Delfia) immunofluorimetric assay were employed for detection of LH in the sera and in chromatofocusing fractions. B-LH and testosterone were also measured in the sera. RESULTS: Hormone data (mean +/- SEM for normal and renal subjects respectively) were 15.5 IU/l +/- 1.2 and 26.9 +/- 7.2 (B-LH), 6.0 IU/l +/- 0.3 and 16.5 +/- 4.8 (irmaLH), 5.7 +/- 0.5 and 13.6 +/- 4.8 (fluorLH), 25.2nmol/l +/- 2.0 and 12.1 +/- 1.2 (T). The serum B:I ratios were 2.6 +/- 0.1 and 2.6 +/- 0.2 (controls, irmaLH and fluorLH respectively) and 1.7 +/- 0.1 and 2.1 +/- 0.1 (chronic renal failure group). Recovery of LH from the column was 111 +/- 12% (mean +/- SEM) by IRMA and 104 +/- 7% by IFMA for the ten FPLC runs. The median pI for the LH distribution measured by both assays was in the region 6.54-6.40 for subjects with chronic renal failure and 6.09-5.95 for controls. Median pI was negatively correlated to the B-LH:irmaLH (P < 0.0001) and B-LH:fluorLH ratios (P = 0.002) in the serum. Furthermore, the proportion of isoforms recovered in the pH region 6.25-5.50 increased with increasing T levels in the serum (P < 0.004). CONCLUSION: The distribution of LH in serum of men on haemodialysis is more basic than in normal men. The greater the proportion of more acidic LH species, particularly those with a pI of between 5.50-6.25, the higher the ratio of LH bioactivity to immunoactivity and consequently testosterone levels.

Adolescent↗

PubMed1994

Changes in the kinetics and biopotency of luteinizing hormone in hemodialyzed men during treatment with recombinant human erythropoietin.

To investigate the effect of recombinant human erythropoietin (rh-EPO) on the hypothalamo-pituitary-gonadal axis in end-stage renal failure, plasma luteinizing hormone (LH) concentration release was assessed by frequent blood sampling (every 10 min), both during an 8-h baseline period and after stimulation with an iv bolus of gonadotropin-releasing hormone (GnRH). Seven adult hemodialyzed men were studied before and after partial correction of anemia by rh-EPO treatment. LH was determined by an in vitro Leydig cell bioassay (bio-LH) and a highly sensitive immunoradiometric assay. Pulsatile bio-LH secretion and clearance characteristics were assessed by multiple-parameter deconvolution analysis. Although the rh-EPO treatment did not lead to a change in average concentrations of plasma bio-LH, the mass of hormone released per secretory burst more than doubled, and the estimated bio-LH production rate increased from 8.8 +/- 2.3 to 15.6 +/- 5.2 IU/L per hour (P = 0.05). The lack of change in mean plasma bio-LH is explained by a simultaneous decrease in plasma half-life from 106 +/- 27 to 67 +/- 19 min (P < 0.02). The decrease in the plasma half-life of bio-LH was closely associated with the rise in hematocrit, suggesting an effect of the increased red blood cell mass on LH distribution space and elimination kinetics. As a consequence of the changes in hormone kinetics, the incremental amplitudes of the plasma concentration pulses of bio-LH increased from 112 to 121% of nadir levels (P < 0.05), resulting in a more distinctly pulsatile pattern of hormone signals.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Insulin-like growth factor-I stimulated growth and progesterone production by granulosa-lutein cells. Lack of interaction with physiological concentrations of luteinizing hormone and follicle stimulating hormone.

This study examined the effect of physiological concentrations of insulin-like growth factor-I (IGF-I), follicle stimulating hormone (FSH) and luteinizing hormone (LH) alone and in combination on growth and progesterone production by human granulosa-lutein cells. Granulosa-lutein cells were obtained from patients (n > 5) undergoing in-vitro fertilization (IVF) or gamete intra-Fallopian transfer (GIFT) treatment. Cells were cultured for 2 and 4 days in the presence of physiological concentrations of human LH (code 68/40, 5 IU/l), FSH (code 83/575, 20 IU/l), or IGF-I (30 ng/ml) alone and in combination. Medium was changed every 2 days. No change in cell number (relative to each patient's own control) was observed after treatment with FSH or LH alone or in combination at any time. IGF-I alone produced a 117 +/- 8% and 176 +/- 15% (mean +/- SEM, n = 5) increase in cell number after 2 and 4 days respectively. This increase was unaffected by the addition of LH or FSH at any time. Basal progesterone secretion was variable (1633, 975-2409 nmol/l, median and interquartile range, day 2) and decreased with time in culture (564, 375-1089 nmol/l, day 4). After 2 days culture progesterone output increased by 116 +/- 5% of control in response to LH and 153 +/- 13% (mean +/- SEM, n = 5) of control in response to IGF-I. After 4 days, LH and IGF-I stimulated progesterone levels by 279 +/- 52% and 264 +/- 37% (mean +/- SEM, n = 5) respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Androstenedione↗

PubMed1993

Physiological oestradiol administration does not change the biological to immunological ratio of LH in serum from post-menopausal women.

OBJECTIVE: We investigated the effect of chronic physiological concentrations of oestradiol on the bioactivity (B) and immunoactivity (I) of LH in serum using radioimmunoassay (RIA) and a sensitive immunoradiometric (IRMA) assay. DESIGN: Twelve post-menopausal, hysterectomized women received a 50-mg subcutaneous E2 implant, in the absence of progestogen treatment. Pretreatment serum samples were obtained on two occasions for measurement of E2 and FSH by radioimmunoassay and for measurement of LH by bioassay (BIO), immunoradiometric assay and radioimmunoassay. Further serum samples were obtained monthly for 6 months for assay as above. RESULTS: The serum E2 level (basal levels < 70 pmol/l) rose following implant (P < 0.01) peaking at 1 month (mean 454, range 356-580 pmol/l) and remaining within premenopausal physiological levels for 6 months. There were falls in FSH, LH-RIA, LH-IRMA and LH-BIO (P < 0.001). There was no change in the B:I ratio for B:I-RIA or B:I-IRMA for LH which were 1.8 and 3.3, respectively pretreatment and 1.7 and 2.9 after 1 month's treatment. CONCLUSION: The treatment of post-menopausal women with 50-mg E2 subcutaneous implants produces physiological premenopausal E2 levels for at least 6 months. There is no change in the B:I ratio of LH using either the RIA or IRMA during chronic E2 treatment.

Biological Assay↗