bluuebunny/crossref_metadata_2025 huggingface dataset:
Serum free IGF‐I, total IGF‐I, IGFBP‐1 and IGFBP‐3 levels in an elderly population: relation to age and sex steroid levels
Authors: Janssen  , Stolk  , Pols  , Grobbee  , De Jong  , Lamberts
Published: March 2003

BACKGROUND

Most previous studies concerning the relationship between IGF‐I and age used assays measuring total IGF‐I. Although free IGF‐I is considered of greater biological relevance, little is known about its relationship with sex steroids levels in elderly healthy subjects.

MEASUREMENTS

In a cross‐sectional study of 218 healthy people (103 men, 115 women) aged 55–80 years we measured serum total and free IGF‐I, IGFBP‐1 and IGFBP3 levels and sex steroids. Free androgen index and free oestradiol index were used as an indicator for free oestradiol and free testosterone levels, respectively.

RESULTS

Free IGF‐I levels did not decline with age in the whole study population. Free IGF‐I levels even increased in individuals above 70 years of age in comparison to those aged between 55 and 70 years (mean ± SE 0.106 ± 0.007 nmol/l vs. 0.086 ± 0.004 nmol/l, P = 0.009). Total IGF‐I and IGFBP‐3 decreased with age (r = −0.20, P = 0.005 and r = −0.24, P = 0.001, respectively). Total IGF‐I levels were positively related with free oestrogen index in both sexes. Free IGF‐I did not relate to free oestrogen or androgen index. In women only, free IGF‐I was related positively with DHEAS while IGFBP‐1 was inversely correlated with DHEAS.

CONCLUSIONS

Free IGF‐I levels do not decrease with age and are even higher in individuals above 70 years. There was no relationship between free IGF‐I and free androgen or oestrogen index in either gender. We hypothesize that higher free IGF‐I levels in older persons may be the consequence of selective survival in the cohort: subjects with high free IGF‐I levels may live longer. The absence of a relationship between free IGF‐I levels and free androgen and oestrogen indices suggests that there is no direct interaction between the biological activity of circulating IGF‐I levels and sex hormone production in a healthy ageing population.
Retinoid X receptor expression in the normal pituitary and clinically ‘non‐functioning’ pituitary tumours
Authors: Gittoes  , McCabe  , Verhaeg  , Sheppard  , Franklyn
Published: March 2003

OBJECTIVE

The glycoprotein hormone common α‐subunit is frequently expressed in clinically ‘non‐functioning’ tumours (NFTs) of the anterior pituitary, despite normal levels of T3 and gonadal steroids. This observation suggests abnormal negative‐feedback regulation of the α‐subunit by T3 and gonadal steroids in NFTs. We have previously documented reduced expression of thyroid hormone receptor (TR) variants in NFTs compared to normals and proposed that this observation may, in part, explain the defective negative regulation. Due to the important role of retinoid X receptors (RXRs) in transactivating TR‐mediated transcriptional regulation, via heterodimer formation, we hypothesize that aberrant RXR isoform expression in NFTs may contribute to the defective negative regulation of the α‐subunit by T3.

DESIGN

Comparison of RXR isoform protein and mRNA expression in NFTs and normal pituitaries.

PATIENTS AND TUMOURS

Twenty clinically non‐functioning pituitary tumours and 27 normal pituitaries were obtained for analysis.

MEASUREMENTS

Immunocytochemistry and semiquantitative RT‐PCR was performed on tumours and normal pituitaries to determine the relative levels of expression of RXR isoform proteins and mRNAs, respectively.

RESULTS

RXRα was expressed in a similar proportion (approximately 50%) of both normal human pituitaries and NFTs, while RXRβ and γ were each observed in 26% of normals but were undetectable in NFTs. The application of semiquantitative RT‐PCR revealed similar levels of mRNAs encoding the RXRα and RXRβ isoforms in normals and NFTs but significantly reduced expression of RXRγ mRNA was observed in NFTs.

CONCLUSIONS

We propose that abnormal RXR isoform expression in clinically ‘non‐functioning’ pituitary tumours may contribute to abnormal T3‐mediated negative regulation of α‐subunit production.
Serum leptin concentrations in patients with thyroid disorders
Authors: Yoshida Tadashi , Momotani Naoko , Hayashi Matsuhiko , Monkawa Toshiaki , Ito Kunihiko , Saruta Takao
Published: March 2003

OBJECTIVE

Leptin, the obese gene product, is secreted exclusively by adipocytes and is thought to act as a lipostatic signal that regulates body weight homeostasis. We previously reported that thyroid hormone is one of the up‐regulating factors of leptin in vitro. T3, at physiological concentrations, stimulates leptin mRNA expression and leptin secretion by 3T3‐L1 adipocytes. The aim of this study was to explore the role of thyroid hormone in the regulation of leptin in humans.

DESIGN AND PATIENTS

A total of 59 non‐obese women aged 38.4 ± 1.8 years (mean ± SEM) were studied: 19 patients with hyperthyroidism, 17 patients with hypothyroidism, and 23 normal control subjects. The correlation between serum leptin concentrations and body mass index (BMI) was analyzed, and serum leptin levels were compared among the three groups.

MEASUREMENTS

Serum leptin concentrations were measured by radioimmunoassay.

RESULTS

Serum leptin concentrations after logarithmic transformation were correlated significantly (P < 0.05) with BMI in the hyperthyroid (r = 0.46), the hypothyroid (r = 0.84), and normal (r = 0.63) groups. Even though age, body weight, and BMI were similar in all groups, serum leptin levels in the hypothyroid patients (5.30 ± 1.12 μg/l) were significantly (P < 0.05) lower than in the hyperthyroid and normal groups (6.87 ± 0.66 and 6.58 ± 0.68 μg/l, respectively).

CONCLUSIONS

These results indicate that thyroid hormone may play an important role in the appropriate secretion of leptin in humans.
Inhibin A and inhibin B in women with polycystic ovarian syndrome during treatment with FSH to induce mono‐ovulation
Authors: Anderson R. A. , Groome N. P. , Baird D. T.
Published: March 2003

OBJECTIVE

Polycystic ovary syndrome (PCOS) is characterized by the presence of numerous small antral follicles arrested at a diameter of less than 10 mm. As development of large antral follicle(s) can be stimulated by the administration of FSH, it has been suggested that the arrest of follicle development is due to a relative lack of or resistance to FSH. We have measured the concentration of FSH and LH and the ovarian hormones oestradiol, inhibin A and B, in relation to the dynamics of follicular development in women with PCOS under basal conditions and during treatment with FSH.

DESIGN

The concentrations of FSH, LH, oestradiol, inhibin A and B were measured in women with PCOS who were untreated (n = 9) or following progesterone‐induced menses (10 cycles in six women) and control women on day 3 of a normal cycle (n = 10). Serial measurements of the same hormones were made during induction of ovulation with low dose of exogenous FSH in the women with PCOS who had been treated with progesterone. The dynamics of follicle development were measured by serial pelvic ultrasound examinations during treatment with FSH in PCOS and in the follicular phase of control cycles.

PATIENTS

Nine anovulatory untreated women with PCOS were compared with 10 normal women and six women with PCOS undergoing FSH treatment.

RESULTS

The concentrations of inhibin B and LH were higher in both groups of women with PCOS than in normal control women on day 3. In untreated women with PCOS the concentration of inhibin A was also significantly elevated compared to control women (P < 0.01) but not in women pretreated with progesterone. Basal concentrations of oestradiol were also significantly higher in women with PCOS than in the early follicular phase of the normal cycle. There were no significant differences in the concentration of FSH between the groups. Treatment of women with PCOS with low doses of FSH stimulated the development of a single dominant follicle which had an identical rate of growth and secretion of oestradiol and inhibin A to that observed in spontaneous cycles in normal women. In contrast to normal women, the concentration of inhibin B rose 7‐fold following FSH treatment and remained elevated until the luteal phase.

CONCLUSIONS

The raised concentrations of inhibin A and B in women with PCOS probably reflects the increased number of small antral follicles characteristically present in that condition. The striking similarity in the dynamics of growth of the dominant follicle and the pattern in concentration of oestradiol and inhibin A in normal women and in women with PCOS treated with modest amounts of FSH, suggests that the arrest of follicle development in PCOS may be due to a relative deficiency of FSH which may in turn be secondary to increased secretion of either or both inhibin forms.
Effects of chronic opioid antagonism on gonadotrophin and ovarian sex steroid secretion during the luteal phase
Authors: Rossmanith Winifried G. , Monn Marcel , Benz Reiner
Published: March 2003

OBJECTIVES

Since short‐term opioid antagonism increases LH pulsatility during the luteal phase in women, we postulated that prolonged opioid antagonism may also accelerate the LH secretory episodes at this time. If so, the functional and temporal links between secretory episodes of pituitary LH and oestradiol (E2) and progesterone (P) release from the mature human corpus luteum may be disrupted.

STUDY DESIGN

Prolonged opioid blockade with the oral antagonist naltrexone (100 mg daily) was effected in eight women during the entire luteal phase of their cycles. Following documented ovulation in both placebo (control) and naltrexone cycles, blood samples were obtained daily and frequently (every 10 minutes for 10 h) on days 6–8 after ovulation.

MEASUREMENTS

In all blood samples, LH, E2 and P were determined by IRMA.

RESULTS

Compared to control cycles, the temporal organization and the endocrine characteristics of the luteal phase remained virtually unchanged during chronic opioid blockade. Periodic fluctuations were detected (by cluster analysis) in LH, E2 and P data series established by frequent sample collections in both the control and naltrexone cycles. LH secretory profiles were remarkably similar during control and naltrexone cycles, and the E2 and P secretory episodes tended to be coupled to LH pulses during both cycles. As determined by time–series analysis, the cross‐correlations between the LH/E2 and LH/P data series remained unaltered by opioid blockade.

CONCLUSIONS

Chronic opioid antagonism with naltrexone did not disrupt the temporal organization or endocrine characteristics of the luteal phase. In particular, prolonged opioid blockade did not change LH secretory patterns. The functional and temporal links between LH inputs and sex steroid release from the mature corpus luteum remained unaffected by prolonged opioid antagonism. In contrast to the effects of short‐term opioid blockade on LH pulsatile release during the luteal phase, the effects of chronic opioid antagonism on LH release may be transient and may not persist throughout the entire luteal phase, suggesting desensitization of the opiate receptors.
Calcitonin deficiency in early stages of chronic autoimmune thyroiditis
Authors: Borges Maria F. , Abelin Neusa M. A. , Menezes Fernanda O. M. , Dahia Patricia L. M. , Toledo Sergio P. A.
Published: March 2003

OBJECTIVES

Although calcitonin (Ct) deficiency has been described in chronic autoimmune thyroiditis (CAT) it is unclear at what stage in the disease it develops. We have analysed the Ct secretory responses of patients in two different evolutionary stages of CAT, namely the goitrous and atrophic phases.

DESIGN

We studied the Ct response to combined calcium (2 mg/kg) and pentagastrin (0.5 μg/kg) intravenous infusion in 27 patients with CAT and 30 normal adult controls. The cases were divided into two groups. The first comprised eleven women with CAT and goitrous subclinical hypothyroidism (GH), aged 28.6 ± 10.1 years—at diagnosis they had increased thyroid autoantibody titres and cytological features compatible with stages 1 and 2 of Hashimoto's thyroiditis. The second comprised 16 females with CAT and an atrophic thyroid confirmed by ultrasound scan, aged 38.0 ± 9.2 years—these patients were severely hypothyroid at diagnosis and were termed AH (atrophic hypothyroidism). Both groups (GH and AH) received replacement doses of thyroxine sufficient to restore euthyroidism for at least six months before the stimulation tests. Control group (C) consisted of 20 healthy women (A), aged 30.0 ± 9.6 years, and 10 healthy men (B), aged 34.7 ± 8.0 years. Serum Ct was measured by IRMA. The Ct secretory response was related to thyroid size and cytological data, when available.

RESULTS

Basal Ct concentrations in groups GH (0.08 ng/l, median) and AH (0.07 ng/l, median) were significantly lower than those of female controls (0.58 ng/l, median). Stimulated Ct peak values in groups GH (0.08 ng/l, median) and AH (0.19 ng/l, median) were significantly lower than those of female controls (13.61 ng/l, median). Also, both basal (2.72 ng/l, median) and stimulated Ct levels (35.73 ng/l, median) in male controls were significantly higher than in female controls given already. A positive correlation between the Ct secretory reserve and thyroid dimensions, evaluated by ultrasound scan, was found only in patients with thyroid atrophy (AH; rs = 0.61,P < 0.05).

CONCLUSIONS

We have found low basal and stimulated calcitonin values in patients with chronic autoimmune thyroiditis and thyroid enlargement, which represents an early phase of chronic autoimmune thyroiditis. Our data have also confirmed previous findings of deficient calcitonin secretion in advanced stages of chronic autoimmune thyroditis in which thyroid atrophy is usually found. These findings may be associated with C‐cell destruction following progressive, nonspecific follicular cell damage caused by lymphocytic infiltration and fibrosis of the gland.
Effect of long‐term growth hormone treatment on carbohydrate metabolism in children with growth hormone deficiency
Authors: Seminara Salvatore , Merello Giovanna , Masi Stefano , Filpo Antonio , La Cauza Francesca , D'Onghia Giovanna , Martelli Elena , Loche Sandro
Published: March 2003

OBJECTIVE

Growth hormone (GH) has well known effects on carbohydrate metabolism. We have evaluated the effects of long‐term growth hormone (GH) therapy on carbohydrate metabolism in children with classical GH deficiency (GHD) or GH neurosecretory dysfunction (GHND)

STUDY DESIGN

Glucose, insulin and C‐peptide concentrations at baseline and during oral glucose tolerance test (OGTT) were measured before and after 18 and 36 months of GH therapy (0.6–0.8 IU/Kg/week in 6 evening doses) in 13 GHD and 7 GHND children (15 boys and 5 girls, 15 prepubertal and 5 early pubertal; age at diagnosis 2.11–13.1 y).

RESULTS

Mean fasting insulin and C‐peptide concentrations after 18 months were similar to the pretreatment values, while after 36 months they were significantly higher than before treatment. Fasting glucose concentrations were similar to pretreatment both after 18 and 36 months. The mean areas under the curve (AUC) during OGTT for glucose, insulin, and C‐peptide were significantly increased after 18 and 36 months. There were no differences between GHD and GHND patients. During the treatment period 10 of the 15 prepubertal patients entered puberty. A significant increase of insulin and C‐peptide concentrations occurred after 36 months of GH treatment in the patients that remained prepubertal during treatment as well as in those who were pubertal when treatment was started. In three of our patients GH treatment caused glucose intolerance, which resolved after 6–12 months of a normal calorie low‐simple carbohydrate diet without requiring discontinuation of treatment.

CONCLUSION

Our data show that long‐term GH treatment in GH deficient children causes hyperglycaemia and increased insulin secretion. These effects may in some patients induce glucose intolerance, which is reversible with appropriate dietary measures and does not require discontinuation of treatment.
Characterization of serum SHBG isoforms in prepubertal and pubertal girls
Authors: Bedecarrás  , Gryngarten  , Ayuso  , Escobar  , Bergadá  , Campo
Published: March 2003

OBJECTIVE

SHBG is a circulating glycoprotein that binds dihydrotestosterone, testosterone and oestradiol with high affinity and low capacity. In girls, serum concentrations of SHBG gradually decrease with age due to a true fall in concentration and not to a change in the binding characteristics. The aim of our study was to determine the pattern of serum SHBG isoforms in normal girls in early childhood (ECh), late childhood (LCh) and puberty (P).

SUBJECTS

Fifteen normal girls were studied. They were divided into three groups according to their age: ECh: 3.7 ± 0.9 years (mean ± SD, n = 5); LCh: 6.4 ± 0.5 years (n = 5); and P: 13.4 ± 1.5 years (n = 5).

METHODS AND MEASUREMENTS

Preparative isoelectric focusing was used to isolate SHBG isoforms according to their isoelectric point (pI).Three groups of isoforms were isolated: SI: pI 5.2–5.4; SII: pI 5.4–5.6 and SIII: pI 5.6–5.8. Steroid levels in serum were determined by RIA.

RESULTS

The relative distribution of SHBG isoforms (% of the total SHBG recovered, mean ± SD) in the three groups of girls studied was: ECh: SI: 25.8 ± 9.9, SII: 53 ± 10.5 and SIII: 21.2 ± 1.6; LCh: SI: 8.8 ± 3.1, SII: 58.8 ± 12.2 and SIII: 31.8 ± 8.6; P: SI: non‐detectable; SII: 51.6 ± 12.6 and SIII: 48.4 ± 12.6.

CONCLUSION

These results indicate that serum SHBG is more heterogeneous before puberty. A considerable proportion of acidic isoforms are present early in life; they decrease during the prepubertal period and disappear when sexual development is completed. After puberty the glycoprotein is more homogeneous and an important proportion of more basic isoforms is present. At puberty serum SHBG not only falls in concentration but also has an altered sialic acid content which modulates its circulating half‐life.
Screening for primary aldosteronism with a logistic multivariate discriminant analysis*
Authors: Rossi Gian Paolo , Rossi Ermanno , Pavan Edoardo , Rosati Nicoletta , Zecchel Roberto , Semplicini Andrea , Perazzoli Franco , Pessina Achille C.
Published: March 2003

OBJECTIVE

Primary aldosteronism (PA) is the most common endocrine cause of curable hypertension, but no single test unequivocally identifies it. Accordingly, we investigated the usefulness of a logistic multivariate discriminant analysis (MDA) approach for PA screening.

DESIGN

Generation of a logistic MDA function based on retrospective analysis of biochemical tests in a large cohort of referred patients with/without confirmed Conn's adenoma (CA), followed by prospective validation of the model.

PATIENTS

We investigated 574 selected hypertensives: 206 (32 with and 174 without CA) retrospectively, 48 (with a 13% prevalence of CA) prospectively for the validation of the model, and 320 referred hypertensives (with a 3.4% prevalence of CA) similarly evaluated. Patients were referred to a specialised centre for hypertension (4th Clinica Medica—University of Padua) and to a department of Internal Medicine of a regional hospital (Reggio Emilia).

MEASUREMENTS

In all patients we measured several demographic and biochemical variables and performed a captopril test. A stepwise analysis of variance, based on a model fitted with several different variables, identified baseline (sALDO) and captopril‐suppressed plasma aldosterone (cALDO), supine plasma renin activity (sPRA) and K+ as the most informative. Therefore, two models of logistic MDA with sPRA, K+, and either sALDO (model A) or cALDO (model B) were developed and used. ROC analysis was also performed to assess the optimal cut‐off values.

RESULTS

The model B of MDA provided the best performance and identified CA with 100% sensitivity and 81% accuracy. When used prospectively it showed 100% sensitivity, both in the Padua (88% accuracy) and in the Reggio Emilia series (90% accuracy). However, at both institutions most patients with idiopathic hyperaldosteronism (IHA) were also detected.

CONCLUSIONS

Thus, although developed from patients with confirmed Conn's adenoma, a strategy based on multivariate discriminant analysis can be used prospectively for accurate screening for primary aldosteronism. Furthermore, it was proven to be accurate and applicable to patients tested with similar modalities at a different institution. Although this approach did not provide a clear‐cut discrimination of Conn's adenoma from idiopathic hyperaldosteronism, it may avoid unnecessary and costly further testing in patients with a low probability of primary aldosteronism.
Clinical and biochemical response following withdrawal of a long‐acting, depot injection form of octreotide (Sandostatin‐LAR®)
Authors: Stewart Paul M. , Stewart Susan E. , Clark Penny M. S. , Sheppard Michael C.
Published: March 2003

OBJECTIVE

Monthly injections of Sandostatin‐LAR® have been shown to be an effective therapy for patients with acromegaly. Because of an ongoing need to assess a patients response to definitive therapy such as surgery and/or radiotherapy, we aimed to evaluate GH levels and acromegaly symptom scores in patients withdrawing from Sandostatin‐LAR®.

DESIGN AND PATIENTS

12 patients with acromegaly previously treated with Sandostatin‐LAR®, 20–40 mg intramuscularly every 28 (n = 9) or 42 (n = 3) days for 12–36 months were studied at monthly intervals for 4 months following the withdrawal of the drug.

MEASUREMENTS

Hourly fasting serum GH measurements between 0800 h and 1200 h, serum IGF‐1 and symptom scores were undertaken at 4,8,12 and 16 weeks following the last injection of Sandostatin‐LAR®. MRI/CT scans of the pituitary were undertaken at 16 weeks and compared to scans taken on Sandostatin‐LAR® within the previous 10 months.

RESULTS

Serum GH rose progressively from 7.7 (1.5 to 14.6) (median (range)) mIU/l at 4 weeks to 9.9 (1.5–21.8), to 12.6 (4.9–31.9) (P < 0.05 vs 4 weeks) and to 13.1 (6.0–39.1) mIU/l (P < 0.002) at 8, 12 and 16 weeks, respectively, following cessation of Sandostatin‐LAR®. IGF‐1 rose from 38.5 (12.6–73.8) nmol/l at 4 weeks to 62.4 (37.4–159) at 16 weeks (P < 0.002) and mean symptom score (comprising headache, sweating, arthralgia, paraesthesiae, tiredness) from 4.0 (0 to 10) (4 weeks) to 4.5 (0–9) (8 weeks) to 6.0 (2–10) (12 weeks) to 6.5 (4–12) (16 weeks, P < 0.05). Individual GH profiles indicated a rise in GH in 5/12 patients between weeks 4–8 and between weeks 8–12 in a further 5/12 patients. There were no changes in pituitary tumour size following discontinuation of Sandostatin‐LAR®.

CONCLUSIONS

GH and symptom scores rise progressively following discontinuation of Sandostatin‐LAR® in acromegalic patients. However, GH and symptom scores remain suppressed in some patients for at least 8 weeks following cessation of Sandostatin‐LAR®. We suggest that a withdrawal period of 3 months from Sandostatin‐LAR® is required in order to perform a meaningful re‐assessment of GH and clinical status.
Prevalence of Ras mutations in thyroid neoplasia
Authors: Esapa Christopher T. , Johnson Sarah J. , Kendall‐Taylor Pat , Lennard Tom W. J. , Harris Philip E.
Published: March 2003

OBJECTIVE

Mutations at codons 12, 13 or 61 of ras which result in constitutive activation occur frequently in human malignancies. There have been varied reports on their prevalence and hence their likely significance in the pathogenesis of primary thyroid neoplasia. To address this, we have examined a large series of benign and malignant thyroid tumours for ras mutations.

DESIGN

Genomic DNA was analysed for the presence of mutations at codons 12, 13 and 61 of H‐ras, K‐ras and N‐ras by allele‐specific oligonucleotide hybridization. Direct DNA sequencing was used to confirm the mutations.

PATIENTS

A total of 90 samples with benign (66) and malignant (24) thyroid disease were investigated.

RESULTS

A total of 14/90 (15.5%) samples had a ras mutation. All mutations were at codon 61 of either N‐ras or K‐ras. The positive cases were 1/25 (4%) nodular goitre, 7/38 (18%) follicular adenoma, 4/9 (44%) follicular carcinoma, 1/1 anaplastic carcinoma, 1/1 follicular variant of papillary carcinoma, and 1 metastatic follicular carcinoma in which the primary tumour had the same mutation.

CONCLUSIONS

Our data demonstrate a relatively low overall prevalence of ras mutations in thyroid neoplasia, with a predominance in follicular neoplasms. Their presence in follicular adenomas suggests that they may have an early aetiological role in the development of thyroid neoplasia.
Long‐term substitution therapy of hypogonadal men with transscrotal testosterone over 7–10 years
Authors: Behre Hermann M. , Von Eckardstein Sigrid , Kliesch Sabine , Nieschlag Eberhard
Published: March 2003

OBJECTIVE

Testosterone (T) substitution of hypogonadal men by conventional intramuscular injection of T esters is not considered optimal because it induces unphysiologically fluctuating serum T levels. In contrast, scrotal T patches produce normal serum (T) levels mimicking diurnal variations. In order to assess the quality of this new form of T substitution we followed hypogonadal men treated by transdermal T up to 10 years.

PATIENTS

Eleven men aged 35.9 ± 9.8 years (mean ± SD) at the beginning of the study were treated with transscrotal T patches (Testoderm®) because of primary (n = 4) or secondary (n = 7) hypogonadism. Clinical examinations were performed every 3 months during the first 5 years and every 6 months thereafter. All 11 patients were seen for 7 years and some for longer periods: eight for 8 years, six for 9 years and four for 10 years.

MEASUREMENTS AND RESULTS

With daily application of one patch T levels rose from 5.3 ± 1.3 nmol/l (mean ± SE) to 16.7 ± 2.6 nmol/l at month 3 and remained in the normal range throughout treatment. Serum 5α‐dihydrotestosterone (DHT) rose from 1.3 ± 0.4 nmol/l to 3.9 ± 1.4 nmol/l and oestradiol from 52.3 ± 9.3 to 71.3 ± 9.6 pmol/l and remained stable without significant variations throughout the observation period. Patients reported absence of local side‐effects except for occasional itching. No relevant changes occurred in clinical chemistry, including total cholesterol levels and triglycerides. Haemoglobin and erythrocyte counts remained normal. Bone density measured by QCT increased slightly from 113.6 ± 5.4 to 129.7 ± 9.3 mg/cm3 during the observation period (P = 0.028). In the nine patients aged < 50 years prostate volumes showed a small but insignificant increase from 16.8 ± 1.5 to 18.8 ± 2.1 ml during transscrotal T therapy. In the two older patients prostate volume remained constant or decreased slightly during T therapy after an initial increase in the previously untreated patient. Prostate specific antigen levels were constantly low in all patients.

CONCLUSION

Transscrotal testosterone patches are well‐accepted and safe in long‐term testosterone substitution therapy for male hypogonadism.
Hypothalamic derangement in traumatized patients: growth hormone (GH) and prolactin response to thyrotrophin‐releasing hormone and GH‐releasing hormone
Authors: De Marinis  , Mancini  , Valle  , Bianchi  , Gentilella  , Liberale  , Mignani  , Pennisi  , Della Corte
Published: March 2003

OBJECTIVE

To study the impact of severe head injury on both basal pituitary hormone secretion and the response to exogenous synthetic hypothalamic releasing factors (TRH and GHRH) in order to evaluate sequential changes in the central control of hypophyseal secretion in the days following head injury.

DESIGN

Prospective clinical study

PATIENTS

21 comatose male patients with head injuries, each intubated and ventilated, intensively monitored and having no previous endocrine problems.

MEASUREMENTS

AND RESULTS The GH and PRL responses to TRH (200 μg iv), and the GH and PRL responses to GHRH (50 μg iv) were evaluated, respectively, on the days 1 and 16 and on days 2, 7and 15 after admission. Daily blood samples were also collected for GH, PRL, TSH, T3 and T4 evaluation. In the basal samples taken on days 2, 7 and 15, IGF‐I and cortisol were also determined. Nitrogen balance was assessed daily. On the day 1, TRH increased GH levels from 9.8 ± 2.2 to 22.4 ± 6.5 mU/l but failed to induce GH release on day 16. The PRL response to TRH was normal. The GH peak response to GHRH was normal on the day 2 (35.7 ± 13.9 mU/l), but was increased on days 7 and 15 (68.3 ± 10.7 mU/l on day 7; 73.8 ± 9.2 mU/l on day 15, P < 0.01 vs. day 2). We found a significant PRL response to GHRH during the whole period of observation. In the daily evaluation, nitrogen balance was negative in all patients from the day 1 to 5. On average, all patients reached a positive nitrogen balance on the day 8. Compared to the day 2, a statistical increase in IGF‐I concentration was observed on days 7 and 15.

CONCLUSIONS

The evaluation of pituitary dynamics in the acute phase of a severe injury demonstrates an alteration of GH and PRL secretion, which correlate with the aminergic and/or peptidergic derangements. Taken together, our data suggest augmented tone of both GHRH and somatostatin in the very acute phase, while an imbalance of releasing factors is hypothesized in the following days. The metabolic consequences of this neuroendocrine pattern could be advantageous in the rapid recovery from the cascade of events produced by the trauma, as documented by the increase in IGF‐1 levels and the positive nitrogen balance.
Macroprolactinaemia: validation and application of the polyethylene glycol precipitation test and clinical characterization of the condition
Authors: Olukoga  , Kane
Published: March 2003

OBJECTIVE

The clinical characteristics and natural history of macroprolactinaemia are yet to be fully established and there is currently no widely accepted simple in vitro test for routine identification of the condition. This study was designed to further validate the polyethylene glycol (PEG) precipitation test with assessment of percentage prolactin recovery (%R), for the detection of macroprolactinaemia and clinically characterize cases identified using the test.

DESIGN

Analytical validation and application of the PEG precipitation test for diagnosis of macroprolactinaemia and a retrospective case‐notes review of some of the patients identified with the condition.

PATIENTS

Sera from 188 patients with elevated serum prolactin (PRL) concentrations were screened for macroprolactinaemia. Seventeen of the patients who were under follow‐up at the local teaching hospital and were identified to have macroprolactinaemia were systematically characterized clinically.

MEASUREMENTS

Prolactin was measured in sera, fractions from gel filtration chromatography and supernatant obtained after PEG precipitation, by the DELFIA fluoroimmunoassay.

CLINICAL ENDPOINTS

Initial serum PRL and symptoms and their response to dopamine agonist therapy; imaging of the pituitary gland; serum PRL and symptoms after cessation of dopamine agonist therapy; course of serum PRL and symptoms without dopamine agonist therapy.

RESULTS

The within‐batch coefficient of variation (CV) of the PEG precipitation test ranged between 2.8 and 7.3% while the between‐batch CV ranged between 3.4 and 9.7%. Intra‐individual variability up to five months was 9.9%. A prolactin recovery ≤ 40% was indicative of macroprolactinaemia, while the condition was unlikely to be present at values > 50%. The prevalence of macroprolactinaemia was 15% without sex difference. Clinical characterization of 17 patients showed modest initial serum PRL concentrations and there was imaging evidence of a coexisting pituitary adenoma in three of them. Dopamine agonist therapy resulted in substantial falls in serum PRL and this was associated with improvement or resolution of symptoms in some patients. Stoppage of dopamine agonist resulted in rebound hyperprolactinaemia in all cases. Spontaneous improvement in symptoms occurred in three patients but hyperprolactinaemia persisted in all those who were not on treatment.

CONCLUSIONS

The PEG precipitation test with assessment of ‘free’ prolactin has been shown to be reproducible and sensitive for the detection of macroprolactinaemia. Many of the patients who had macroprolactinaemia presented with at least one symptom of the hyperprolactinaemic syndrome. Dopaminergic therapy may influence the course of both serum PRL and symptoms in some of these patients.
p16 (INK4a, MTS‐1) gene polymorphism and methylation status in human pituitary tumours
Authors: Jaffrain‐Rea  , Ferretti  , Toniato  , Cannita  , Santoro  , Di Stefano  , Ricevuto  , Maroder  , Tamburrano  , Cantore  , Gulino  , Martinotti
Published: March 2003

OBJECTIVE

The p16 gene, which encodes a physiological inhibitor of the cyclin D‐CDK4 complex, is now considered as an important tumour‐suppressor gene in a variety of tumours. A marked reduction of its expression has been reported to occur without significant genetic alterations in human pituitary adenomas, although rare point mutations of uncertain functional significance have been described. On the other hand, p16 gene silencing due to hypermethylation has been reported in several human primary tumours. The aim of this study was to further investigate the pathogenetic events leading to p16 gene inactivation in pituitary tumours.

DESIGN

To screen a european series of human pituitary tumours for p16 gene alterations and possible gene hypermethylation.

PATIENTS

A representative series of 31 human pituitary tumours—30 macroadenomas, including a MEN‐1 non‐secreting pituitary adenoma and a non‐MEN‐1 familial giant GH‐secreting adenoma, and one FSH‐secreting pituitary carcinoma—was studied.

METHODS

Polymerase chain reaction/single strand conformation polymorphism (PCR‐SSCP) analysis was used to screen for p16 gene alterations in all cases. Direct sequencing of PCR‐products was obtained by the di‐deoxynucleotide method where suspected abnormalities of the PCR‐SSCP analysis were observed. In 24 samples, a methylation‐specific PCR assay (MSP‐PCR) was used to determine p16 gene methylation status.

RESULTS

Two sporadic cases of pituitary adenomas had a similar single A to G base substitution leading to an heterozygous Ala140Thr p16 polymorphism, which has not previously been described in such tumours, but is known to be functionally silent. No other p16 abnormality could be suspected from PCR‐SSCP analysis in this series. In contrast, the presence of methylated‐specific PCR products was observed in 20/24 cases (83.3%).

CONCLUSIONS

This study confirms that p16 gene mutations are not involved in the pathogenesis of human pituitary tumours, although polymorphisms can be demonstrated, depending on the population considered. In contrast, the high incidence of hypermethylation of the p16 gene suggests that such an alteration occurs early in pituitary tumours, and may play a role in pituitary tumorigenesis.
Frequent loss of heterozygosity at chromosome 3p14.2–3p21 in human pancreatic islet cell tumours
Authors: Nikiforova Marina N. , Nikiforov Yuri E. , Biddinger Paul , Gnepp Douglas R. , Grosembacher Luis A. , Wajchenberg Bernardo L. , Fagin James A. , Cohen Robert M.
Published: March 2003

OBJECTIVE

Pancreatic islet βcell tumours occur either sporadically or as part of inherited neoplastic syndromes, most commonly multiple endocrine neoplasia (MEN) type 1. Recently, a transgenic mouse model has been established in which the expression of the SV40 large T antigen was targeted to βcells by the rat insulin promoter, leading to the development of multiple pancreatic βcell tumours. In the advanced stages of tumour evolution, these tumours exhibited a high prevalence of loss of heterozygosity (LOH) on mouse chromosomes 9 and 16, at regions syntenic with regions 3q, 3p21, 6q12, 15q24 and 22q of the human genome.

DESIGN

Loss of heterozygosity in human islet cell tumours was analysed in a PCR based approach at regions of the human genome syntenic with the mouse loci linked to pancreatic βcell tumours as well as the MEN1 gene on chromosome 11q13. These included 35 microsatellite markers in the human chromosomal regions 3q, 3p21, 6q12, 11q13, 15q24 and 22q.

PATIENTS

21 patients diagnosed with insulinoma were analysed. Histologically, 16 tumours were benign, while 5 were malignant insulinomas.

RESULTS

Thirteen of 21 (62%) tumours were found to have loss of genetic material on chromosome 3. The shortest region of overlap implicated a deletion at 3p14.2–3p21 region, corresponding to the marker D3S1295. We did not detect a substantial frequency of LOH in the other syntenic regions, except for the region of MEN 1 gene on 11q13 found to be deleted in 6 (29%) cases, including 3 of 4 tumours from MEN 1 families. Deletions of 3p14.2–3p21 were observed in 8 of 15 (53%) benign tumours, and in 5 of 6 (83%) malignant neoplasms.

CONCLUSIONS

These results indicate the high frequency of 3p14.2–3p21 deletions in human pancreatic βcell neoplasms. These finding suggest the presence of a tumour suppressor gene in this region, that may be important in the microevolution of these tumours towards malignancy.
Acute dexamethasone administration enhances GH responsiveness to GH releasing peptide‐6 (GHRP‐6) in man
Authors: Pinto Ana‐Cláudia A. R. , Finamor Jr Francisco E. , Lengyel Ana‐Maria J.
Published: March 2003

OBJECTIVE

Acute administration of glucocorticoids stimulates GH secretion probably by a decrease in hypothalamic somatostatin release. GHRP‐6 is a synthetic hexapeptide that increases GH secretion by a mechanism of action not yet fully known, but apparently not by inhibition of hypothalamic somatostatin release. The aim of this study was to evaluate the effect of acute dexamethasone administration on GH responsiveness to GHRP‐6 in man.

DESIGN

One group of subjects received iv GHRP‐6 (1 μg/kg), GH‐releasing hormone (GHRH; 100 μg), GHRH plus GHRP‐6 or saline 3.5 h after oral acute dexamethasone administration (4 mg; at 0600 h). A second study group was treated with GHRP‐6, GHRH or GHRP‐6 plus GHRH after placebo ingestion, following the same protocol.

PATIENTS

Sixteen normal subjects (mean age: 29 ± 3.3 years), with normal BMI (22.4 ± 2.0 kg/m2), were studied. Eight subjects received dexamethasone and the other eight were treated with placebo.

MEASUREMENTS

Serum GH was measured by a two site monoclonal antibody immunofluorometric assay.

RESULTS

In the placebo‐treated subjects, mean peak GH (mU/l; mean ± SE) and AUC (mU.min/l) values after GHRP‐6 administration (peak: 43.8 ± 9.0; AUC: 2262.0 ± 459.2) did not differ from those observed after GHRH injection (peak: 49.8 ± 12.0; AUC: 2903.4 ± 872.6). The association of the two peptides markedly increased GH levels (peak: 172.4 ± 34.2; AUC: 10393.0 ± 1894.8) compared with the isolated administration of GHRP‐6 or GHRH. In the subjects who received dexamethasone 3.5 h before saline injection, GH baseline values were significantly higher than those observed after 90 min of sampling (12.4 ± 9.4 vs. 4.6 ± 2.0). Mean GH peak and AUC values after GHRP‐6 (peak: 78.8 ± 11.0; AUC: 4114.6 ± 588.2) and after GHRH administration (peak: 46.8 ± 16.0; AUC: 3006.8 ± 1010.0) did not differ significantly in the dexamethasone‐treated subjects. In this study group, the administration of the two peptides together caused a significant increase in both peak (119.2 ± 16.0) and AUC values (7377.0 ± 937.2) compared with the response obtained after each peptide alone. When the two groups were compared, a significant increase in GH responsiveness to GHRP‐6 was observed after dexamethasone administration compared with placebo. No differences in GH response to GHRH, or to the administration of the two peptides together, were seen between the two groups.

CONCLUSIONS

Oral dexamethasone, at a dose of 4 mg, enhances GH releasing peptide‐6‐induced GH release when administered 3.5 h earlier. These results suggest that dexamethasone and GHRP‐6 could act at different sites of GH releasing mechanisms. Further studies are necessary to elucidate these findings.
Hypoglycaemia associated with the production of insulin‐like growth factor II and insulin‐like growth factor binding protein 6 by a haemangiopericytoma
Authors: Hoekman Klaas , Van Doorn Jaap , Gloudemans Ton , Maassen Johannes A. , Schuller Alwin G. P. , Pinedo Herbert M.
Published: March 2003

Non‐islet‐cell tumour‐induced hypoglycaemia (NICTH) is, in most cases, attributable to tumour production of insulin‐like growth factor II (IGF‐II). Tumour‐derived IGF‐II has a higher than normal molecular weight (big ‘IGF‐II’) and an impaired ability to form the normal ternary 150 kD complex with IGF binding protein‐3 (IGFBP‐3) and the acid‐labile subunit (ALS). Consequently, tumoral IGF‐II circulates mainly in smaller binary complexes which have a higher bioavailability than the ternary complex.

We had the opportunity to analyze IGFs and IGF‐related factors in both pre‐ and post‐operative blood, tumour tissue and tumour cyst fluid from a patient with a disseminated haemangiopericytoma and severe hypoglycaemia. In addition, the effect of serum and tumour cyst fluid on autophosphorylation of the insulin receptor was examined.

Patient serum contained low levels of IGF‐I, IGFBP‐3 and ALS, while the concentrations of IGFBP‐2 and IGFBP‐6 were markedly elevated. The total level of circulating IGF‐II was within the normal range, but Biogel P‐60 gel filtration of patient serum revealed that 77% of the IGF‐II was present in high molecular weight forms (normal: 10–15%), which decreased to 53% after partial removal of the tumour. Most of the IGF‐II immunoreactivity in pre‐ and post‐operative patient serum was associated with 50–60 kD complexes with only a minimal contribution (<10%) from the 150 kD complex. Tumour cyst fluid contained excessive amounts of both big IGF‐II and IGFBP‐6.

Northern blot analysis of total mRNA isolated from the tumour demonstrated high expression of the IGF‐II gene and abundant 1.1 kb IGFBP‐6 transcript, while the genes encoding IGFBP‐3, ‐4 and ‐5 were only weakly expressed and mRNA of IGFBP‐1, ‐2 and IGF‐I could not be detected. mRNAs for the IGF type II receptor could be easily demonstrated, whereas those for the insulin‐ and IGF type I receptor were hardly detectable. In contrast to patient serum tumour cyst fluid strongly stimulated the insulin receptor in vitro. The present study suggests an important role of the simultaneous production of IGF‐II and IGFBP‐6 in the pathophysiology of tumour‐induced hypoglycaemia.
Absence of somatostatin receptor type 2 A mutations and gip oncogene in pituitary somatotroph adenomas
Authors: Petersenn Stephan , Heyens Maria , Lüdecke Dieter K. , Beil Frank U. , Schulte Heinrich M.
Published: March 2003

OBJECTIVE

Somatostatin, acting via specific receptors in the anterior pituitary, tonically inhibits pituitary growth hormone secretion and somatotroph proliferation. Reduction of growth hormone secretion and tumour regression in GH‐secreting pituitary adenomas treated with long‐acting somatostatin analogues varies widely. In 30–40% of these tumours dominant somatic mutations of the Gsα gene (gsp) have been demonstrated leading to constitutive adenylyl cyclase induction. A relationship between somatostatin sensitivity and tumour pathogenesis in some tumours has been suggested. Changes in the function of the somatostatin receptor or intracellular signal elements may be of relevance. Somatostatin receptor type 2 A (sst2A) and Gi2 are proposed to mediate selectively the inhibition of GH release in the somatotroph. We therefore investigated the presence of sst2A mutations and gip oncogene in somatotrophic pituitary adenomas.

DESIGN

Tumour samples from 15 patients with pituitary somatotroph adenomas were obtained. RNA was isolated and used for reverse transcription and subsequent polymerase chain reaction. All samples were screened for the presence of sst2A mutations and of the gip oncogene by SSCP analysis and sequencing. For comparison, the gsp oncogene was examined. The relationship between clinical data and molecular analysis results was investigated.

RESULTS

Seven of the tumours harboured a gsp mutation. No mutations affecting the sst2A protein were found in any of the tumours analysed. Furthermore, gip oncogene was absent in all tumours.

CONCLUSION

Mutations of the somatostatin receptor type 2 A and the gip oncogene are unlikely to be involved in the pathogenesis of acromegaly.
Spironolactone as a single agent for long‐term therapy of hirsute patients
Authors: Spritzer Poli Mara , Lisboa Karen O. , Mattiello Simone , Lhullier Francisco
Published: March 2003

OBJECTIVE

To assess the androgen‐suppressing effect of spironolactone, and the use of this drug as a single agent in the long‐term therapy of hirsute patients with either polycystic ovary syndrome (PCOS) or idiopathic hirsutism (IH). Standard cyproterone acetate (CPA) treatment was used to evaluate the results obtained with spironolactone.

DESIGN

Prospective randomized study.

PATIENTS

Forty‐six hirsute women were separated randomly into two groups, stratified for polycystic ovary syndrome. For 12 months, Group 1 (21 patients, 10 PCOS) received spironolactone only (200 mg/day). Group 2 (23 patients, nine PCOS) received CPA (50 mg/day) with ethinyl oestradiol (35 μg/day).

MEASUREMENTS

Ferriman–Gallwey clinical score for hirsutism and serum testosterone, androstenedione, and LH levels.

RESULTS

In IH patients, hirsutism regressed equally with spironolactone (21 ± 2–14.5 ± 2) and CPA (23 ± 2–13 ± 2). In PCOS patients, the mean score for hirsutism after 12 months was significantly lower with CPA (12 ± 1) than with spironolactone (16 ± 1). Testosterone levels did not change with spironolactone; with CPA there was a decrease from baseline in PCOS (47% and 51%, 6 and 12 months) and IH patients (31% and 30%). Androstenedione levels also declined from baseline in CPA‐treated PCOS patients (38% and 39%, 6 and 12 months). Androgen levels were significantly different between the groups after 6 and 12 months. LH levels decreased with CPA (72%) but not with spironolactone.

CONCLUSION

Our results suggest that spironolactone used as a single agent is as effective as cyproterone acetate combined with oestradiol for long‐term treatment of patients with idiopathic hirsutism. In PCOS patients, spironolactone is still effective for reducing hirsutism; however, for treatment of the hormonal or metabolic manifestations associated with PCOS, it may be necessary to combine spironolactone with either an antigonadotrophic agent or a drug that improves peripheral insulin sensitivity.