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Biomedical subjects

H G Burger

Publications and source records attributed to H G Burger.

At least 73 records · Page 4Linked to original sources
PubMed1996

Bone turnover markers and bone density across the menopausal transition.

We measured lunbar spine and femoral neck bone mineral density (BMD); urine markers of bone resorption; serum markers of bone formation; and serum gonadotrophin, estradiol and inhibin concentrations in a population-based cohort of 281 women aged 45-57 yr. Women were classified into pre-, peri-, and postmenopausal groups, depending on menstrual bleeding patterns. Compared with premenopausal women, BMD was lower only in postmenopausal women but not in women currently using hormone replacement therapy (HRT). BMD decreased with age in the perimenopausal group. Compared with premenopausal women, perimenopausal women had 20% greater urine N-telopeptide excretion (P < 0.05) and a doubling of gonadotrophin levels (P < 0.01), whereas serum estradiol and bone formation marker concentrations were no different. Postmenopausal Women had greater levels of bone turnover markers (P < 0.0001), except free deoxypyridinoline and type I procollagen propeptide. Among postmenopausal women, bone resorption markers were lower in those using HRT. Levels of nearly all bone turnover markers were positively related to serum FSH concentrations (P < 0.0001). Overall, the major independent predictors of BMD were age, urine N-telopeptide, serum bone alkaline phosphatase, and serum, FSH, whereas urine free deoxypyridinoline was positively related to BMD in pre- and perimenopausal women. In conclusion, the perimenopause is associated with elevated bone resorption rates and declining BMD, and factors in addition to estrogen deficiency may also contribute to the pathogenesis of postmenopausal osteoporosis.

Aging↗
PubMed1996

Bone mineral density and hormone levels in menopausal Australian women.

To assess the relationships between bone mineral density (BMD) at the lumbar spine and femoral neck and menopausal status, age, physical variables, and lifestyle and gynecological factors. BMD and follicle-stimulating hormone (FSH), estradiol and inhibin levels were measured in 167 women born in Australia, aged 46-57 years, who had no record of receiving hormone replacement therapy. Using the premenopausal group as a baseline, the FSH level was higher in peri- and postmenopausal subjects (p < 0.0005), and estradiol and inhibin levels in the postmenopausal women were lower (p < 0.0005). Mean (+/- SE) lumbar spine and femoral neck BMD were 15 +/- 3% and 10 +/- 3% lower, respectively, in postmenopausal than in premenopausal women. Lumbar spine BMD decreased with increasing age in perimenopausal women only (p < 0.005), and femoral neck BMD decreased with increasing age in the pre-, peri-(p < 0.05) and postmenopausal women. The difference between femoral neck BMD in the pre- and postmenopausal women was explained by the difference in age between these groups, whereas for lumbar spine BMD the menopausal status was an additional determining factor. There was a negative effect of smoking on femoral neck BMD (p < 0.05) in postmenopausal women. In the perimenopausal decade the femoral neck BMD is primarily dependent on age, whereas lumbar spine BMD is dependent on both age and menopausal status.

Aging↗
PubMed1995

Inhibin and activin are demonstrable by immunohistochemistry in ovarian tumor tissue.

Elevated serum immunoreactive inhibin concentrations have been reported in patients with mucinous and granulosa cell tumors of the ovary. The present study aimed to determine whether the inhibins and/or the related peptides, the activins, were demonstrable within ovarian tumor tissue. Immunohistochemical analyses were performed on 11 ovarian tumors, 5 mucinous, 3 serous, 1 granulosa, 1 clear cell, and 1 metastatic colonic cancer. Both monoclonal and polyclonal antisera specific for inhibin-A, activin-A, and activin-B, and their alpha-, beta A- and beta B-subunits were used. The mucinous cells of all five mucinous tumors showed positive staining for activin-A and activin-B, and their beta A- and beta B-subunits, and three stained positive for inhibin-A and the alpha-subunit. The granulosa cell tumor also showed positive staining for inhibin-A and the activins. The remaining tumors were negative. The findings are consistent with the hypersecretion of inhibin (and possibly activin) by some ovarian malignancies and suggest that immunohistochemistry for the inhibins and the activins should be explored further in the classification of ovarian malignancies.

Activins↗
PubMed1995

Dietary flour supplementation decreases post-menopausal hot flushes: effect of soy and wheat.

Plants contain compounds with oestrogen-like action called phytoestrogens. Soy contains daidzin, a potent phytoestrogen, and wheat flour contains less potent enterolactones. We aimed to show in 58 postmenopausal women (age 54, range 30-70 years) with at least 14 hot flushes per week, that their daily diet supplemented with soy flour (n = 28) could reduce flushes compared with wheat flour (n = 30) over 12 weeks when randomised and double blind. Hot flushes significantly decreased in the soy and wheat flour groups (40% and 25% reduction, respectively < 0.001 for both) with a significant rapid response in the soy flour group in 6 weeks (P < 0.001) that continued. Menopausal symptom score decreased significantly in both groups (P < 0.05). Urinary daidzein excretion confirmed compliance. Vaginal cell maturation, plasma lipids and urinary calcium remained unchanged. Serum FSH decreased and urinary hydroxyproline increased in the wheat flour group.

Adult↗
PubMed1995

Efficacy and tolerance of Menorest compared to Premarin in the treatment of postmenopausal women. A randomised, multicentre, double-blind, double-dummy study.

Two-hundred and fourteen (214) menopausal women with moderate to severe vasomotor symptoms, aged 40-65 years, were randomised. After a 4-week treatment-free period, each women received a continuous regimen of Menorest 50 twice weekly or Premarin 0.625 mg daily, for 12 weeks. Didrogesterone 10 mg was also given to all women for 12 days of every 28-day cycle. The objectives were to compare the efficacy and safety profiles of Menorest and an oral estrogen. A statistically significant reduction in the mean number of hot flushes occurred in each group compared to baseline with a decrease from 7.1 at baseline to 0.9 at 12 weeks in the Menorest group, and from 6.7 to 0.5 in the oral estrogen group; there was no statistically significant difference between the two groups (P = 0.36). With each successive treatment cycle, there was a continuous improvement in the number of hot flushes. The incidence and severity of menopausal symptoms were reduced in the same manner in both groups. There were no statistically significant differences in the mean plasma estradiol and estrone concentrations between the two treatment groups after 10 weeks of therapy. The mean estradiol to estrone ratio was similar in both groups, as was the number of adverse events observed. In summary, Menorest was as effective as an oral estrogen in alleviating menopausal symptoms.

Administration, Cutaneous↗
PubMed1995

Aspects of current and future inhibin research.

Inhibin was first isolated in 1985. Major progress has been made in defining various aspects of its structure and physiology, using a heterologous radioimmunoassay. Current research is aimed at characterizing the nature of the circulating forms of inhibin and is examining whether there are sex-specific roles for inhibins A and B. It has been recognized that various forms of epithelial and stromal ovarian cancer produce members of the inhibin peptide family but the precise nature of these products is not yet clear. The recognition that the inhibin subunits together with follistatin are expressed locally within the pituitary has lead to an investigation of their possible roles in intrapituitary regulation. It is clear that these peptides also have intragonadal roles. Of particular current interest is the nature of the signals that control the specificity of cellular peptide production and that determine whether a particular cell produces inhibin or activin. The inhibins are members of a complex family with many potential roles in physiology and pathophysiology. The role of the inhibins in feedback control of follicle stimulating hormone in the male, particularly, remains unclear. New applications for inhibin and related peptides are likely to be developed.

Female↗
PubMed1995

Follicular fluid insulin-like growth factor-I and insulin-like growth factor-II concentrations vary as a function of day 3 serum follicle stimulating hormone.

We determined follicular fluid concentrations of insulin-like growth factor (IGF)-I, IGF-II and inhibin as a function of day 3 serum follicle stimulating hormone (FSH) in 16 women undergoing follicular fluid aspiration in preparation for in-vitro fertilization and embryo transfer. Follicular fluid concentrations of IGF-I and IGF-II were significantly less in the 'low' FSH group as compared to the 'high' FSH group. The mean IGF-I concentration was 67.6 ng/ml [confidence intervals (CI) 51.6-92.5] in the 'low' FSH group compared to 87.1 ng/ml (CI 72.8-104.2; P < 0.025) in the 'high' FSH group. Mean IGF-II concentrations were 354.8 ng/ml (CI 297.8-422.9) in the 'low' FSH group compared to 489.8 ng/ml (CI 384.6-624.5; P < 0.05) in the 'high' FSH group. Follicular fluid inhibin concentrations did not differ between groups. These differences in follicular fluid IGF as a function of day 3 FSH may raise questions regarding the role growth factors play in the physiological processes of the ageing follicle.

Adult↗
PubMed1995

The endocrinology of the menopausal transition: a cross-sectional study of a population-based sample.

In a study of the endocrinology of the perimenopausal years, levels of serum FSH, estradiol (E2), immunoreactive inhibin (INH), testosterone, and sex hormone-binding globulin were measured in a population-based sample of 380 women (mean age, 49.4 yr; range, 45.6-56.9 yr). Subjects were divided into women who reported continuing regular menstrual cycles (27%; group I), a change in menstrual flow without a change in frequency (23%; group II), a change in frequency but no change in flow (9%; group III), changes in both frequency and flow (28%; group IV), and at least 3 months since their last menstrual period (13%; group V). After adjusting for age and body mass index, the geometric mean FSH increased across menstrual groups and, compared with group I, was 53% higher in group IV (P < 0.0005) and 253% higher in group V (P < 0.0001). Age- and body mass index-adjusted geometric means for E2 and INH in group V were 54% and 53% of those in group 1, respectively (P < 0.005, P < 0.0001). Women in group V who did not have a menstrual period in the next year had higher FSH and lower E2 and INH levels than those who subsequently went on to have at least one more menstrual period (P < 0.05). FSH was negatively correlated with E2 (r = -0.30) and INH (r = -0.39), whereas INH was positively correlated with E2 (r = 0.45). We conclude that an increase in serum FSH and decreases in E2 and INH are the major endocrine changes associated cross-sectionally with the menopausal transition.

Androgens↗
PubMed1994

A prospective study of inhibin in granulosa cell tumors of the ovary.

Elevated preoperative serum inhibin concentrations have been reported in patients with granulosa cell tumor of the ovary. The aim of this study was to determine if elevations in serum inhibin predated clinical recurrence in patients with a diagnosis of granulosa cell tumor. Twenty-seven consecutive patients with granulosa cell tumor were followed prospectively to assess the relationship between serum inhibin concentrations and disease status. The serum inhibin concentrations in normal postmenopausal women were < 77-130 U/liter. In patients with granulosa cell tumor at initial surgery, mean inhibin concentrations preoperatively were 2831 U/liter in 4 postmenopausal subjects (range 2130-3323 U/liter) and 3680 U/liter in each of 2 premenopausal women. In 5 postmenopausal subjects with a histological diagnosis of granulosa cell tumor who underwent secondary surgery because of a recurrent palpable mass, mean inhibin concentrations were 4216 U/liter (range 2672-7360). In 3 patients with known or suspected residual disease despite a secondary debulking operation the serum inhibin concentrations were 475, 1000, and 2541 U/liter. In 13 subjects who were clinically disease free with a previous diagnosis of granulosa cell tumor, serum inhibin concentrations remained within the normal range for reproductive status. We conclude: (1) Preoperative serum inhibin concentrations are typically elevated sevenfold above the normal premenopausal follicular phase levels in women with granulosa cell tumor; (2) after surgery, serum inhibin levels may become elevated up to 2 years before further surgery is undertaken; and (3) serum inhibin concentrations appear to be a valuable tumor marker for the diagnosis of primary or recurrent granulosa cell tumor.

Adult↗
PubMed1994

Determinants of forearm mineral density and its correlation with fracture history in women.

In order to evaluate the role of single photon absorptiometry (SPA) in the prediction of osteoporotic fracture risk, 1935 women, referred for measurement of forearm mineral density (FMD) at the distal radial site, were studied by questionnaire in a cross-sectional design. There was no significant decline in FMD until the age of 47, after which there was a linear decline with age of about 1.2% per year. There was no relationship between age and FMD, or forearm mineral content (FMC), in premenopausal women. There was a fall in FMD with the number of years since menopause, after correcting for the effects of age, of approximately 0.5% per year. Body weight was positively correlated with FMC in postmenopausal women. The duration of exposure to hormone replacement therapy (HRT) was positively correlated with FMD, and the magnitude of this effect was reduced the longer the delay between the onset of the menopause and the commencement of HRT. There was no significant association of FMD with calcium intake, weight-bearing exercise, tobacco or alcohol consumption, or family history of osteoporosis. FMD was significantly lower in postmenopausal women who reported fractures after the age of 25, after correcting for age and years postmenopause. In conclusion, a low FMD is predictive of a past history of fractures and may therefore be capable of predicting future fracture risk.

Absorptiometry, Photon↗
PubMed1994

Serum inhibin during lactation: relation to the gonadotrophins and gonadal steroids.

OBJECTIVE: The aims of the study were to describe the changes in serum immunoreactive inhibin (INH) during normal lactation and to examine the relations between INH, oestradiol (E2) and follicle stimulating hormone (FSH), particularly during the first weeks post partum. DESIGN: Blood samples were obtained from normally lactating women for hormone measurements at daily intervals until discharge from hospital, and subsequently at weekly intervals until the resumption of menses, or one year post partum. SUBJECTS: Eighteen breast feeding women aged 27-36 years volunteered for the study. MEASUREMENTS: INH, FSH, luteinizing hormone (LH), prolactin (PRL), E2, and progesterone (P4) were measured by standard radioimmunoassays. Non-linear modelling was used to quantify the hormone patterns observed. RESULTS: Hormone levels were compared with those found in the follicular phase of the normal menstrual cycle. Levels of INH fell rapidly in the first week post partum and remained at the lower end of the follicular phase range for the period of study, rising only just prior to resumption of menses. E2 fell more slowly, into the follicular phase range, reaching the lower end of that range only at about approximately 100 days post partum. FSH levels were suppressed initially below the follicular phase range, commencing to rise 4.7-24 days post partum, reaching a plateau high in the follicular phase range 17.5-53 days post partum, and subsequently showing a slow decline. Human chorionic gonadotrophin (hCG), initially measured because of its cross-reactivity in the LH assay, fell rapidly post partum and LH remained in the low follicular phase range for several weeks. PRL fell slowly throughout and was still elevated at 150 days post partum, while P4 fell very rapidly and was less than 1 nmol/l until just prior to first menses. CONCLUSIONS: Inhibin levels fall rapidly post partum and remain low until close to the time of resumption of follicular activity and menses. The post partum rise in serum FSH appears to be much more closely related to falling oestradiol levels than to the very early and rapid fall in inhibin. Oestradiol thus appears to be the predominant negative feedback factor influencing FSH secretion during the post partum period. The low inhibin levels may allow FSH to rise to levels high in the follicular phase range under the predominant negative feedback control of oestradiol. Inhibin levels do not appear to be a suitable marker of returning fertility.

Adult↗
PubMed1994

The menopause: when it is all over or is it?

The menopause is defined rigorously as the cessation of menstruation as a result of ovarian follicular depletion. Although in common clinical usage, the term is used to encompass the menopausal transition, a period which may average 4 years in duration, and during which alterations in menstrual regularity and/or flow may be accompanied by somatic or psychological symptoms. Measurement of serum follicle-stimulating hormone (FSH) with or without oestradiol (E2) is frequently advocated as providing a useful indicator of menopausal status. Several studies have shown an increase in serum FSH, with or without decrease in E2, in women over the age of 40 years who continue to cycle regularly. Abrupt fluctuations in serum FSH and E2 may be observed, with typically post menopausal levels subsequently returning to the normal reproductive range. In a cross sectional study, of regularly cycling women randomly selected from the Melbourne community, and over the age of 45 years, 7% had FSH levels typical of the post menopause, and 39% had levels above those found during the follicular phase in women aged less than 35 years. It is concluded that serum FSH is of little diagnostic value in the assessment of menopausal status, which can currently be made only on clinical grounds. An elevated serum FSH level cannot tell us reliably 'when it is all over'.

Adult↗
PubMed1994

Dehydroepiandrosterone sulfate and anovulation increase serum inhibin and affect follicular function during administration of gonadotropins.

To test the hypothesis that testosterone (T) derived from circulating dehydroepiandrosterone sulfate (DS) or produced in excess within the anovulatory ovary is a follicular regulator capable of stimulating inhibin secretion. DS and inhibin were determined by RIA in residual serum samples from in vitro fertilization cycles and analyzed along with other parameters using analysis of variance and stepwise multiple linear regression after log transformation of the RIA data. It was predicted that the serum concentration of inhibin would be higher in women with anovulation than in normal subjects and that the serum inhibin concentration would have a positive regression coefficient on the serum DS concentration. The serum concentrations of inhibin (P < 0.01) and estradiol (P < 0.001) on the day of hCG treatment were higher in women with anovulation than in normal subjects, as was the number of oocytes retrieved (P < 0.001). The FSH and LH doses (both P < 0.005) and age (P < 0.001) were significantly lower, and the average duration of gonadotropin therapy was 1 day shorter (P < 0.001) in anovulatory patients. There was no significant difference in serum DS (P > 0.2). Regression analysis showed that serum inhibin was positively related to the number of oocytes (P < 0.001) and serum DS (P = 0.05), with an increase in anovulatory subjects (P < 0.025). The duration of treatment with gonadotropins was related positively to the patient's age (P < 0.001) and negatively to serum DS (P < 0.025), with a decrease in anovulatory subjects (P < 0.025). The number of oocytes obtained was negatively related to age (P < 0.001) and positively to serum DS (P < 0.005). These data are consistent with a stimulatory effect of follicular T derived from either circulating DS or the anovulatory ovary, which affects the secretion of inhibin, the duration of gonadotropin treatment, and the number of oocytes retrieved.

Adult↗
PubMed1994

Diagnostic role of follicle-stimulating hormone (FSH) measurements during the menopausal transition--an analysis of FSH, oestradiol and inhibin.

This review examines the role of follicle-stimulating hormone (FSH) measurement in assessing the significance of symptoms and possible continuing fertility during the menopausal transition. Follicle-stimulating hormone measurement is advocated frequently as a useful diagnostic tool in perimenopausal patients. Several investigators have shown that the serum FSH level increases in the early--mid-follicular and early postovulatory phases in women over the age of 40 years who continue to experience regular menstrual cycles. The serum oestradiol level may fall (although this is controversial) and the immunoreactive inhibin level falls, being inversely correlated with the rising FSH level. When alterations in menstrual cyclicity or flow commence, signalling the onset of the menopausal transition, FSH levels may change abruptly, rising into the normal postmenopausal range and falling again into the range normally seen in young fertile women. Oestradiol and inhibin generally fluctuate in parallel with each other but inversely to FSH, although at times oestradiol in particular may be increased markedly. Postmenopausal FSH levels may be followed by endocrine evidence compatible with normal ovulation. After the menopause, FSH levels rise 10-15-fold, with low oestradiol and undetectable inhibin levels. It is concluded that FSH measurement is of little value, if any in the assessment of women during the menopausal transition because it cannot be interpreted reliably and because, apparently, ovulatory (and, presumably, potentially fertile) cycles may occur subsequent to the observation of postmenopausal FSH levels. Both oestradiol and inhibin are important negative feedback regulators of circulating FSH.

Adult↗
PubMed1994

Sexuality and the menopause.

Sexual problems are often reported to clinicians by women in the midlife years. Yet few of the epidemiological studies of women in midlife have investigated the relationship of the menopause to sexual functioning. This paper reports the results of a cross-sectional telephone survey of 2001 randomly selected Australian-born women aged between 45 and 55 years. The major outcome variables were questions relating to changes in sexual interest over the prior 12 months, reasons for any changes, occurrence of sexual intercourse, and of unusual pain on intercourse. Logistic regression was used to identify explanatory variables for change in sexual interest. The majority of women (62%) reported no change in sexual interest, although 31% reported a decrease. Decline in sexual interest was significantly and adversely associated with natural menopause (p < 0.01) rather than age, decreased well-being (p < 0.001), decreasing employment (p < 0.01) and symptomatology (vasomotor p < 0.05, cardiopulmonary p < 0.001 and skeletal p < 0.01). Eleven to twelve years of education was associated with a lowered risk of decreased sexual functioning (p < 0.01). Heterogeneous results were reported by users of hormone replacement therapies. Longitudinal studies of large and representative samples are needed to determine the etiology of adverse sexual changes with the menopause and the role of hormone replacement therapies.

Adaptation, Psychological↗
PubMed1993

Elevated serum inhibin concentrations in postmenopausal women with ovarian tumors.

BACKGROUND: Inhibin is an ovarian hormone that inhibits the secretion of follicle-stimulating hormone (FSH) by the anterior pituitary gland. Women with granulosa-cell tumors of the ovary have elevated serum inhibin concentrations, but whether the concentrations are increased in women with other ovarian tumors is unknown. METHODS: We measured serum inhibin and FSH concentrations before surgery in 212 postmenopausal women with suspected ovarian cancer and after surgery in 210 of them. RESULTS: Eighteen of the 22 women (82 percent) with mucinous carcinomas (mucinous cystadenocarcinomas and mucinous borderline cystic tumors) of the ovary had elevated serum inhibin concentrations, whereas only 9 of the 53 women (17 percent) with serous carcinomas (serous cystadenocarcinomas and serous borderline cystic tumors) had elevated levels. Serum inhibin concentrations were also elevated in 2 of 12 women (17 percent) with clear-cell carcinomas, 4 of 26 women (15 percent) with undifferentiated carcinomas, 3 of 3 women (100 percent) with granulosa-cell tumors, and 5 of 27 women (19 percent) with other ovarian cancers. The serum concentrations of inhibin were increased in 2 of 28 women (7 percent) with nonovarian pelvic cancers and 11 of 41 women (27 percent) with benign ovarian diseases. All women but one with initially elevated serum inhibin concentrations had low values one week after surgery. Serum inhibin concentrations correlated negatively with serum FSH concentrations (P = 0.05) in women with granulosa-cell tumors but not in women with other tumors, suggesting that the inhibin secreted by tumors in the latter group has decreased biologic activity. CONCLUSIONS: Serum inhibin concentrations are elevated in most postmenopausal women with mucinous carcinomas of the ovary and in some women with other types of epithelial ovarian tumors. The concentrations fall after tumor removal.

Adenocarcinoma, Clear Cell↗
PubMed1993

Perimenopausal patterns of gonadotrophins, immunoreactive inhibin, oestradiol and progesterone.

In order to assess the possible role of circulating immunoreactive inhibin (INH) during the menopausal transition, two groups of subjects were studied. Four were normal volunteers, three of whom had developed their first symptoms of cycle irregularity at age 45-46 years, the fourth being aged 37, a volunteer for a study involving daily blood sampling found to have a transient rise in serum follicle stimulating hormone (FSH). Six were patients with anovulatory infertility, aged 34-44 years, found to have transitory ovarian failure during attempts at ovulation induction. Intermittent blood samples were obtained for radioimmunoassay of serum FSH, luteinizing hormone (LH), INH, oestradiol (E2), and progesterone. Abrupt changes were observed, with transient elevations of FSH and LH and decreases of INH and E2 into the postmenopausal range, followed by levels more characteristic of reproductive-aged women. It was concluded that typical postmenopausal hormone patterns may occur at the time of entry into the normal menopausal transition, and in some women with anovulatory infertility, but may be completely and relatively abruptly reversible. Elevation of serum FSH into the postmenopausal range, with undetectable INH concentrations, does not provide reliable evidence that the menopause (or permanent ovarian failure) has occurred. INH contributes to elevations of serum FSH during the menopausal transition.

Adult↗