bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of different growth hormone (GH) mutants on the regulation of GH-receptor gene transcription in a human hepatoma cell line
Authors: Deladoey J , Gex G , Vuissoz JM , Strasburger CJ , Wajnrajch MP , Mullis PE
Published: January 2005

OBJECTIVE: G to A transition at position 6664 of the growth hormone (GH-1) gene results in the substitution of Arg183 by His (R183H) in the GH protein and causes a new form of autosomal dominant isolated GH deficiency (IGHD type II). The aim of this study was to assess the bioactivity of this R183H mutant GH in comparison with both other GH variants and the 22-kDa GH in terms of GH-receptor gene regulation. DESIGN AND METHODS: The regulation of the GH-receptor gene (GH-receptor/GH binding protein, GHR/GHBP) transcription following the addition of variable concentrations (0, 12.5, 25, 50 and 500 ng/ml) of R183H mutant GH was studied in a human hepatoma cell line (HuH7) cultured in a serum-free hormonally defined medium. In addition, identical experiments were performed using either recombinant human GH (22-kDa GH) as a positive control or two GH-receptor antagonists (R77C mutant GH and pegvisomant (B-2036-PEG)) as negative controls. GHR/GHBP mRNA expression was quantitatively assessed by RT-PCR amplification after 0, 1, 3 and 6 h incubation. RESULTS: Following the addition of R183H mutant GH, GHR/GHBP mRNA changed at a similar rate to that seen in experiments where 22-kDa GH was added, indicating equal bioactivity. At all times and concentrations studied, the addition of R77C mutant GH, however, resulted in a significantly lower increase (P<0.001) of GHR/GHBP mRNA concentration compared with that caused by the addition of either 22-kDa GH or R183H mutant GH. Furthermore, in additional experiments, pegvisomant resulted in an absolute block of GHR/GHBP mRNA expression identical to that seen in control experiments where no 22-kDa GH was added at all. CONCLUSIONS: These data indicate that the R183H mutant GH, although causing an autosomal dominant form of IGHD has an identical effect on GHR/GHBP transcription as its wild-type, the 22-kDa GH. This implies that the IGHD caused by the R183H heterozygous mutation of the GH-1 gene is mainly due to a block of its regulated GH secretion. In addition, the R77C-GH variant and pegvisomant have an antagonistic effect at the level of GHR/GHBP transcription. All these data were confirmed by run-on experiments. In addition, these data highlight, as far as the GH variants are concerned, that a mutational alteration within the GH-1 gene might cause short stature also on the basis of an altered secretory pathway. This fact has to be taken into consideration when growth retardation is clinically diagnosed and studied at the molecular level. Secretory pathways and, therefore, cell-biological mechanisms are of importance and have to be considered in future not only at the scientific but also at the clinical level.
Aromatase and breast cancer: W39R, an inactive protein
Authors: Nativelle-Serpentini C , Lambard S , Seralini GE , Sourdaine P
Published: January 2005

BACKGROUND: Aromatase (CYP19) catalyzes the conversion of androgens into estrogens. It is in particular involved in development, reproduction and breast cancer. One of its polymorphisms, W39R localized in the N-terminal region of CYP19, significantly decreases breast cancer risk among Japanese women and was chosen for this study. In this work, we studied the structure-function relationships between W39R polymorphism and CYP19 enzyme activity. OBJECTIVE: To examine the kinetic properties of the mutant W39R recombinant protein in transfected human cells devoid of steroidogenic activity. METHODS: Expression vectors for the wild-type or the mutated R39 aromatase were transiently transfected into E293 human embryonal kidney cells. The conversions of androstenedione to estrone and of testosterone and nortestosterone to 17beta-estradiol were assayed by RIA. Expression of recombinant cDNAs was analyzed by semi-quantitative RT-PCR and immunoblotting. RESULTS: W39R recombinant protein was devoid of aromatase activity whatever the substrate used. This absence of activity was not due to the lack of expression of the recombinant enzyme since the mRNA and protein were detected. CONCLUSION: Our present in vitro study shows that the R39 mutant is unable to synthesize estrogens. This work provides a novel observation, being consistent with the fact that Japanese women with the variant allele (arg) have significantly lower risk of developing a breast tumor.
Increased adipose tissue secretion of interleukin-6, but not of leptin, plasminogen activator inhibitor-1 or tumour necrosis factor alpha, in Graves' hyperthyroidism
Authors: Wahrenberg H , Wennlund A , Hoffstedt J
Published: January 2005

OBJECTIVE: This study was designed to investigate adipose tissue secretion of interleukin-6 (IL-6), leptin, tumour necrosis factor alpha (TNF-alpha) and plasminogen activator inhibitor-1 (PAI-1) in Graves' hyperthyroidism. DESIGN: We studied 10 patients before and during (after 8 weeks) anti-thyroid treatment for Graves' hyperthyroidism and 16 healthy, euthyroid control subjects. METHODS: Plasma levels of thyroid hormones and serum/plasma levels of IL-6, leptin, TNF-alpha and PAI-1 were analysed. Subcutaneous fat biopsies were taken for subsequent measurement of IL-6, leptin, TNF-alpha and PAI-1 protein secretion. RESULTS: In patients with Graves' disease, the anti-thyroid treatment resulted in significant reductions of plasma thyroxine and triiodothyronine levels. No differences in serum concentration or adipose tissue secretion of leptin or TNF-alpha were observed either before, as compared with during, anti-thyroid treatment, or in comparison with euthyroid controls. In contrast, plasma PAI-1 activity, but not adipose tissue secretion of PAI-1, was increased both in Graves' disease before as compared with during anti-thyroid treatment (P=0.01) and in thyrotoxic patients compared with euthyroid controls (P=0.0001). Finally, adipose secretion of IL-6 was increased both before (8-fold, P=0.001) and during (6-fold, P<0.0001) treatment as compared with control subjects. Accordingly, serum concentration of IL-6 was also increased by about 50% in thyrotoxic patients as compared with healthy controls (P=0.03). CONCLUSIONS: In Graves' hyperthyroidism regardless of thyroid status, adipose tissue secretion of IL-6, but not of leptin, TNF-alpha or PAI-1, is markedly increased in comparison with euthyroid controls. This suggests that autoimmune thyroidal disorder may regulate adipose tissue release of IL-6.
Genetic analysis of lithium-associated parathyroid tumors
Authors: Dwight T , Kytola S , Teh BT , Theodosopoulos G , Richardson AL , Philips J , Twigg S , Delbridge L , Marsh DJ , Nelson AE , Larsson C , Robinson BG
Published: January 2005

OBJECTIVE: The aim of this study was to determine the primary genetic events that may underlie the formation of parathyroid tumors in patients with lithium-associated hyperparathyroidism (HPT). METHODS: Comparative genomic hybridization (CGH), loss of heterozygosity (LOH) and multiple endocrine neoplasia type 1 gene (MEN1) mutation analysis were used to analyze twelve parathyroid tumors from nine patients with lithium-associated HPT. For comparison, CGH was also carried out in a non-lithium-associated group of thirteen sporadic parathyroid tumors. RESULTS: A higher prevalence of multiglandular disease in the lithium-associated HPT patients compared with the idiopathic sporadic patients was observed (Fisher's exact test, P=0.02). CGH alterations were detected in four lithium-associated parathyroid tumors, involving loss at 1p, 11, 15q, 22q and gain of the X chromosome. In addition, one of these four cases exhibited LOH at 11q13 and was found to contain a novel somatic MEN1 mutation (c.1193insTAC). Although fewer lithium-associated parathyroid tumors were shown to contain genetic alterations compared with the sporadic parathyroid tumors, the changes detected were those frequently associated with both familial and sporadic parathyroid tumorigenesis. CONCLUSION: This is, to our knowledge, the first genetic analysis of parathyroid tumors in lithium-associated HPT patients. Our data indicated that the majority of lithium-associated parathyroid tumors do not contain gross chromosomal alterations and suggest that in most cases the tumorigenic pathway is independent of MEN1 and genes at 1p34.3-pter and 1q21-q32. It is possible that other discrete genetic alterations or epigenetic changes, not screened for in this study, could also be responsible for parathyroid tumorigenesis in lithium-associated HPT.
TNF-alpha gene polymorphism and plasma TNF-alpha levels are related to lumbar spine bone area in healthy female Caucasian adolescents
Authors: Wennberg P , Nordstrom P , Lorentzon R , Lerner UH , Lorentzon M
Published: January 2005

OBJECTIVE: The cytokine tumor necrosis factor alpha (TNF-alpha) is an important regulator of bone metabolism. Polymorphisms in the promoter region of the TNF-alpha gene at positions -308 and -863 have been identified. We investigated whether these polymorphisms and circulating TNF-alpha levels were related to bone mineral density and bone area in adolescent girls. DESIGN: Bone mineral density (BMD), bone area (BA), anthropometric characteristics and biochemical analyses were measured in adolescent girls and compared with regard to TNF-alpha genotype. METHODS: Allelic variants of the TNF-alpha gene in 97 girls, aged 16.9+/-1.2 years (mean+/-S.D.), were identified using polymerase chain reaction and the restriction endonucleases NcoI and TaiI. Bone mineral density and bone area of the femoral neck, lumbar spine and total body were measured using dual energy X-ray absorptiometry. RESULTS: Carriers of the rare -863 A allele (n=25) had higher body weight (P=0.03), lumbar spine BMD (P=0.02), and larger total BA (P=0.03), femoral neck area (P<0.05), and lumbar spine area (P=0.01). The independent predictors of BMD and BA were investigated using multiple regression. The TNF-alpha-863 genotypes (beta=0.18, P=0.03) and the TNF-alpha plasma levels (beta=0.19, P=0.04) independently predicted BA of the lumbar spine but not BA or BMD of any other measured sites. No statistically significant differences in body constitution parameters, biochemical parameters, bone density, or bone area at the measured skeletal sites were found when comparing the groups defined by the allelic variants at position -308 (P=0.17-0.84). CONCLUSIONS: We found the TNF-alpha-863 polymorphism and the TNF-alpha plasma levels to be independent predictors of lumbar spine area in healthy Caucasian adolescent females.
Clinical and molecular analysis of three families with autosomal dominant neurohypophyseal diabetes insipidus associated with a novel and recurrent mutations in the vasopressin-neurophysin II gene
Authors: Rutishauser J , Kopp P , Gaskill MB , Kotlar TJ , Robertson GL
Published: January 2005

OBJECTIVE: To test further the hypothesis that autosomal dominant neurohypophyseal diabetes insipidus (adFNDI) is caused by heterozygous mutations in the vasopressin-neurophysin II (AVP-NPII) gene that exert a dominant negative effect by producing a precursor that misfolds, accumulates and eventually destroys the neurosecretory neurons. METHODS: Antidiuretic function, magnetic resonance imaging (MRI) of the posterior pituitary and AVP-NPII gene analysis were performed in 10 affected members of three unreported families with adFNDI. RESULTS: As in previously studied patients, adFNDI apparently manifested after birth, was due to a partial or severe deficiency of AVP, and was associated with absence or diminution of the hyperintense MRI signal normally emitted by the posterior pituitary, and with a heterozygous mutation in the AVP-NPII gene. In family A, a transition 275G-->A, which predicts replacement of cysteine 92 by tyrosine (C92Y), was found in the index patient, but not in either parent, indicating that it arose de novo. The six affected members of family B had a transversion 160G-->C, which predicts replacement of glycine 54 by arginine (G54R). It appeared de novo in the oldest affected member, and was transmitted in a dominant manner. In family C, six of 15 living affected members were tested and all had a novel transition, 313T-->C, which predicts replacement of cysteine 105 by arginine (C105R). It, too, was transmitted in a dominant manner. As in other patients with adFNDI, the amino acids replaced by the mutations in these three families are known to be particularly important for correct and efficient folding of the precursor. CONCLUSIONS: These findings are consistent with the malfolding/toxicity hypothesis underlying the pathogenesis of adFNDI. Moreover, they illustrate the value of genetic analysis in all patients who develop idiopathic diabetes insipidus in childhood, even if no other family members are affected.
Diagnosis of growth hormone deficiency in adults by testing with GHRP-6 alone or in combination with GHRH: comparison with the insulin tolerance test
Authors: Petersenn S , Jung R , Beil FU
Published: January 2005

OBJECTIVE: The diagnosis of GH deficiency in adults should be made using provocative testing of GH secretion. The insulin tolerance test (ITT) is recommended as the gold standard investigation. Because of the risk of serious complications, patients with epilepsy or known ischemic heart disease should not undergo this test. GHRP-6 is a synthetic hexapeptide that releases GH by binding to specific hypothalamic and pituitary receptors. We assessed the diagnostic capability of GH stimulation by GHRP-6 alone or in combination with GHRH in comparison to the results of an ITT. DESIGN: Twenty patients underwent an ITT for suspected pituitary or adrenal disease. Either GHRP-6 (1 microg/kg) alone, or GHRP-6 in combination with GHRH (1 microg/kg) were administered on different days. Blood samples were obtained during a subsequent 90-min period for measurement of GH. RESULTS: Ten patients had a GH peak response of less than 3 microg/l during ITT and were considered growth hormone deficient (GHD). The GH mean peak (+/-S.E.M., range) in this group was 0.7 microg/l (+/-0.3, 0.1-2.9) compared with 14.5 microg/l (+/-3.5, 3.8-40.8) in the group of patients with a GH peak response of more than 3 microg/l (growth hormone sufficient (GS)). For the GHRP-6 test, the GH mean peak was 1.3 microg/l (+/-0.6, 0.1-6.7) in the GHD group versus 25.7 microg/l (+/-5.5, 7.7-54.2) in the GS group. After GHRP-6+GHRH, the GH mean peaks were 4.0 microg/l (+/-1.3, 0.2-11.9) versus 54.7 microg/l (+/-11.1, 13.9-136.0) respectively. During administration of GHRP-6, the only side effects observed were flush symptoms. CONCLUSIONS: Peak GH levels below 7 microg/l for the GHRP-6 test and below 13 microg/l for the combined GHRP-6+GHRH test identified all patients with GH deficiency correctly as defined by ITT. The results suggest that testing with GHRP-6 or GHRP-6+GHRH is as sensitive and specific as an ITT for the diagnosis of adult GH deficiency.
Pharmacokinetics of a new transdermal testosterone gel in gonadotrophin-suppressed normal men
Authors: Rolf C , Kemper S , Lemmnitz G , Eickenberg U , Nieschlag E
Published: January 2005

OBJECTIVE: In a phase I single-centre, open, randomized study, the pharmacokinetics of two doses of a transdermal testosterone gel containing 2.5% testosterone were evaluated in 26 healthy male volunteers. DESIGN: To eliminate the influence of endogenous serum testosterone, gonadotrophins and endogenous testosterone secretion were suppressed by a single intramuscular injection of 400 mg norethisterone enanthate. Fourteen men applied 5.0 g and 12 men applied 2.5 g testosterone gel daily for 10 days. Half the men in each group washed the gel off 10 min after it had been applied. RESULTS: In all the men, a marked suppression of LH, FSH, testosterone, dihydrotestosterone (DHT) and oestradiol was observed after norethisterone treatment. Physiological serum concentrations of testosterone were restored during the 10-day treatment period in the group of men applying 5.0 g testosterone gel. Increasing serum concentrations of testosterone from day 1 to day 10 were observed. Oestradiol and DHT concentrations did not exceed normal values. Washing 10 min after gel application did not influence the resorption of testosterone. A dose of 2.5 g testosterone gel was insufficient to achieve physiological serum concentrations of testosterone. CONCLUSION: Testosterone replacement treatment with 5.0 g of this 2.5% testosterone gel is able to achieve constant physiological testosterone concentrations in gonadotrophin-suppressed men. Washing the skin after 10 min does not influence the pharmacokinetic profile and thus significantly reduces the risk of contamination of female partners or infants.
Short boys treated with growth hormone show normal progression of testicular size and achieve normal serum testosterone concentrations
Authors: Ankarberg-Lindgren C , Norjavaara E , Wikland KA
Published: January 2005

OBJECTIVE: To determine whether there is evidence for impaired testicular function at final height in short boys treated with growth hormone (GH) during their childhood and adolescence. STUDY DESIGN: The analysis was restricted to males who had isolated GH deficiency or idiopathic short stature, and who were included in the Swedish National Registry and the Swedish GH trials. The subjects had to have been treated with GH for at least 4 years; the treatment had to have been started prepubertally, given for at least one year before the onset of puberty and the subjects had to have reached final height. One hundred and eleven boys fulfilled the criteria. METHODS: Testicular volumes were determined by orchidometer in each boy when GH treatment was started and at final height. Samples for testosterone measurements were collected from 77 boys at final height, and were measured by RIA. RESULTS: Each subject had normal testicular size (15 ml or more) and for those in whom concentrations were determined, serum testosterone levels and diurnal rhythm were normal. CONCLUSIONS: The results of our survey do not show evidence of testicular impairment following GH therapy.
Nitric oxide modulation of renal and cardiac hemodynamics in type 2 diabetes
Authors: Dalla Vestra M , Sacerdoti D , Bombonato G , Fioretto P , Finucci G , Saller A , Sfriso A , Bruseghin M , Sambataro M , Velussi M , Baggio B , Nosadini R , Crepaldi G
Published: January 2005

OBJECTIVE: To evaluate endothelial function in type 2 diabetic patients with and without diabetic nephropathy. METHODS: We studied the effects of systemic infusion of the nitric oxide (NO) synthase inhibitor NG-monomethyl-l-arginine (L-NMMA) on cardiovascular and renal hemodynamics in six type 2 diabetic patients with microalbuminuria (D2-MA), six type 2 diabetic patients with normoalbuminuria (D2-NA) and five control subjects. Both type 2 diabetic patients and control subjects had mild arterial hypertension. RESULTS: L-NMMA infusion decreased the cardiac index in all groups. A reduction in glomerular filtration rate (GFR) and an increase in filtration fraction were observed only in controls. Renal plasma flow decreased in controls and D2-NA patients and renal vascular resistance increased in all groups. CONCLUSIONS: The effect of L-NMMA on cardiac output was similar in controls and type 2 diabetic patients with and without diabetic nephropathy. In contrast, the effect on GFR was impaired in both diabetic groups, suggesting that glomerular NO homeostasis is altered in type 2 diabetes. Moreover the discrepancy, in diabetic patients, between cardiac and renal effects during L-NMMA infusion suggests that the modulation of glomerular hemodynamics is independent from NO-regulated cardiac output.
Long-term effects of Graves' ophthalmopathy on health-related quality of life
Authors: Terwee C , Wakelkamp I , Tan S , Dekker F , Prummel MF , Wiersinga W
Published: January 2005

OBJECTIVE: Little is known about the long-term effects of Graves' ophthalmopathy (GO) on health-related quality of life (HRQL) after the eye treatment is considered to be finished. The aim of this study was to quantify these effects using validated HRQL questionnaires. DESIGN: A cross-sectional follow-up study was carried out in GO patients who had started radiotherapy and/or prednisone treatment between 1982 and 1992. METHODS: Between 1998 and 2000 these patients received an HRQL questionnaire containing the SF-36, EuroQol and GO-QOL questionnaires. All patients were invited for a follow-up ophthalmological examination. HRQL scores of the respondents were compared with those of two reference populations of 'healthy' persons and to scores of several other GO populations. RESULTS: One hundred and sixty-eight patients were included; 163 completed the HRQL questionnaire and 154 visited the outpatient clinic. The median follow-up was 11.7 years. A considerable number of symptoms related to GO were found. More than half of the patients had diplopia and 28% had a low visual acuity. Sixty per cent had a proptosis of at least 20 mm. The HRQL scores were considerably better than those of newly diagnosed GO patients (untreated) and GO patients who completed the questionnaire during treatment, but worse than those of 'healthy' persons. Although we did not perform a longitudinal study, we included a selected group of patients who had been treated with radiotherapy and/or prednisone in the Academic Medical Centre of the University of Amsterdam, and though we could not assess HRQL at comparable times after receiving treatment, this is the first study that presents any data on the long-term effects of GO on HRQL. CONCLUSION: GO has a marked negative effect on HRQL, even many years after treatment. These findings suggest that GO should be considered a chronic disease. Aftercare is needed for these patients after their immunosuppressive and surgical treatments.
Expression of cAMP-responsive element binding protein and inducible cAMP early repressor in hyperfunctioning thyroid adenomas
Authors: Peri A , Luciani P , Tonacchera M , Agretti P , Baglioni-Peri S , Buci L , Conforti B , Cioppi F , Biliotti G , Serio M , Vitti P , Chiovato L
Published: January 2005

OBJECTIVE: The pathogenesis of thyroid hyperfunctioning adenomas is still only partially understood and controversy exists about the frequency of gain-of-function mutations of the TSH receptor or G(s)alpha gene, which activate the cAMP pathway. The nuclear transcription factors cAMP-responsive element binding protein (CREB) and inducible cAMP early repressor (ICER) are among the final targets of this signalling cascade. DESIGN: In our study we focused on the expression of CREB and ICER genes in the nodular as well as in the extranodular tissue of hyperfunctioning tumours of the thyroid. METHODS: RT-PCR and Western blot analysis were performed in a series of 14 patients. The presence of an activating mutation of the TSH receptor or of the G(s)alpha gene was ascertained by direct sequencing. RESULTS: The levels of CREB transcripts did not significantly differ in the adenomas and in the normal tissues (CREB/GAPDH, mean optical density+/-s.e.: 0.98+/-0.18 vs 0.88+/-0.27 respectively, P = not significant (N.S.)), although case-to-case variability was observed. The absence of a significant difference between the adenoma and the surrounding normal tissue was maintained after dividing the patients into two groups, according to TSH receptor status. Accordingly, no significant difference in the levels of CREB protein (total and Ser(133)-phosphorylated) was observed between the nodular and the extranodular tissue. In addition, no difference was found in the levels of ICER transcripts (ICER/GAPDH, mean optical density+/-s.e.: 0.52+/-0.11, nodule vs 0.36+/-0.11, normal thyroid, P=N.S.), independently of the TSH receptor gene status (i.e. wild-type or mutated). CONCLUSIONS: Our results support the recent hypothesis that the activation of the cAMP pathway in hyperfunctioning adenomas of the thyroid might be counteracted by opposite events and suggest that complex molecular mechanisms might take part in the pathogenesis of hyperfunctioning tumours.
Objective estimates of the probability of developing hypothyroidism following radioactive iodine treatment of thyrotoxicosis
Authors: Ahmad AM , Ahmad M , Young ET
Published: January 2005

OBJECTIVE: Several risk factors have been shown individually to influence the outcome following radioactive iodine (RAI) therapy in the treatment of hyperthyroidism. However, no attempt has been made to determine their independent prognostic values that could be used in a regression model to provide objective estimates of the probability of developing hypothyroidism. STUDY DESIGN AND METHODS: We audited records of all hyperthyroid patients treated with first dose RAI between 1980 and 1996. Patients were aetiologically categorized into Graves' disease, solitary toxic nodule and toxic multinodular goiter. Following RAI, outcome was categorized as hypothyroidism, euthyroidism and persistent hyperthyroidism. Multiple logistic regression analysis was used to identify significant risk factors, their prognostic values and probability estimates of developing hypothyroidism in the presence of one or more of these factors. RESULTS: The cumulative incidence of hypothyroidism was 55.8% at 1 year and 86.1% at 10 years. Graves' disease (odds ratio: 4.29), presence of thyroid autoantibodies (odds ratio: 3.51), no antithyroid treatment given prior to RAI (odds ratio: 2.50), non-palpable goiter (odds ratio: 2.48) and high RAI dose (odds ratio: 1.90), were identified as significant independent risk factors. We then developed a predictive table that provides objective estimates of developing hypothyroidism. In the absence of all risk factors we can predict an 11.9% probability of developing hypothyroidism; this increases linearly to a 96.4% probability in the presence of all factors. CONCLUSIONS: These objective estimates would help in understanding the relative contributions of the known risk factors, and to predict the probability of developing hypothyroidism following RAI treatment. This would not only help patients make an informed consent for a treatment that would lead to life-long replacement therapy but may also prove useful in calculating the RAI dose that may reduce or delay the onset of developing hypothyroidism.
Vitamin D 1alpha-hydroxylase (CYP1alpha) polymorphism in Graves' disease, Hashimoto's thyroiditis and type 1 diabetes mellitus
Authors: Pani MA , Regulla K , Segni M , Krause M , Hofmann S , Hufner M , Herwig J , Pasquino AM , Usadel KH , Badenhoop K
Published: January 2005

OBJECTIVE: The vitamin D endocrine system plays a role in the regulation of (auto)immunity and cell proliferation. Vitamin D 1alpha-hydroxylase (CYP1alpha) is one of the key enzymes regulating both systemic and tissue levels of 1,25-dihyroxyvitamin D(3) (1,25(OH)(2)D(3)). Administration of 1,25(OH)(2)D(3), whose serum levels were found to be reduced in type 1 diabetes and thyroid autoimmunity, prevents these diseases in animal models. We therefore investigated a recently reported CYP1alpha polymorphism for an association with type 1 diabetes mellitus, Graves' disease and Hashimoto's thyroiditis. DESIGN AND METHODS: Four hundred and seven Caucasian pedigrees with one offspring affected by either type 1 diabetes (209 families), Graves' disease (92 families) or Hashimoto's thyroiditis (106 families) were genotyped for a C/T polymorphism in intron 6 of the CYP1alpha gene on chromosome 12q13.1-13.3 and transmission disequilibrium testing (TDT) was performed. Subsets of affected offspring stratified for HLA-DQ haplotype were compared using chi(2) testing. RESULTS: There was no deviation from the expected transmission frequency in either type 1 diabetes mellitus (P=0.825), Graves' disease (P=0.909) or Hashimoto's thyroiditis (P=0.204). However, in Hashimoto's thyroiditis the CYP1alpha C allele was significantly more often transmitted to HLA-DQ2(-) patients (27 transmitted vs 14 not transmitted; TDT: P=0.042) than expected. The C allele was less often transmitted to HLA-DQ2(+) patients (9 transmitted vs 12 not transmitted; TDT: P=0.513), although the difference was not significant (chi(2) test: P=0.143). A similar difference was observed in type 1 diabetes between offspring with high and low risk HLA-DQ haplotypes (chi(2) test: P=0.095). CONCLUSIONS: The CYP1alpha intron 6 polymorphism appears not to be associated with type 1 diabetes mellitus, Graves' disease and Hashimoto's thyroiditis. A potential association in subsets of patients with type 1 diabetes and Hashimoto's thyroiditis should be further investigated as well as its functional implications.
Agonistic and antagonistic properties of progesterone metabolites at the human mineralocorticoid receptor
Authors: Quinkler M , Meyer B , Bumke-Vogt C , Grossmann C , Gruber U , Oelkers W , Diederich S , Bahr V
Published: January 2005

OBJECTIVE: Progesterone binds to the human mineralocorticoid receptor (hMR) with nearly the same affinity as do aldosterone and cortisol, but confers only low agonistic activity. It is still unclear how aldosterone can act as a mineralocorticoid in situations with high progesterone concentrations, e.g. pregnancy. One mechanism could be conversion of progesterone to inactive compounds in hMR target tissues. DESIGN: We analyzed the agonist and antagonist activities of 16 progesterone metabolites by their binding characteristics for hMR as well as functional studies assessing transactivation. METHODS: We studied binding affinity using hMR expressed in a T7-coupled rabbit reticulocyte lysate system. We used co-transfection of an hMR expression vector together with a luciferase reporter gene in CV-1 cells to investigate agonistic and antagonistic properties. RESULTS: Progesterone and 11beta-OH-progesterone (11beta-OH-P) showed a slightly higher binding affinity than cortisol, deoxycorticosterone and aldosterone. 20alpha-dihydro(DH)-P, 5alpha-DH-P and 17alpha-OH-P had a 3- to 10-fold lower binding potency. All other progesterone metabolites showed a weak affinity for hMR. 20alpha-DH-P exhibited the strongest agonistic potency among the metabolites tested, reaching 11.5% of aldosterone transactivation. The agonistic activity of 11beta-OH-P, 11alpha-OH-P and 17alpha-OH-P was 9, 5.1 and 4.1% respectively. At a concentration of 100 nmol/l, progesterone, 17alpha-OH-P and 20alpha-DH-P inhibit nearly 75, 40 and 35% of the transactivation by aldosterone respectively. All other progesterone metabolites tested demonstrate weaker affinity, and agonistic and antagonistic potency. CONCLUSIONS: The binding affinity for hMR and the agonistic and antagonistic activity diminish with increasing reduction of the progesterone molecule at C20, C17 and at ring A. We assume that progesterone metabolism to these compounds is a possible protective mechanism for hMR. 17alpha-OH-P is a strong hMR antagonist and could exacerbate mineralocorticoid deficiency in patients with congenital adrenal hyperplasia.
Inhibin B plasma concentrations in infertile patients with DAZ gene deletions treated with FSH
Authors: Foresta C , Bettella A , Moro E , Rossato M , Merico M , Garolla A , Ferlin A
Published: January 2005

OBJECTIVE: The DAZ (deleted in azoospermia) gene family on the Y chromosome long arm is the major candidate for the AZFc (azoospermia factor c) phenotype of male infertility and it is expressed only in germ cells. The aim of the study was to assess Sertoli cell function in subjects with AZFc deletions. DESIGN: Case-control, prospective study. METHODS: We have studied six severely oligozoospermic subjects with AZFc-DAZ deletions, and looked whether they responded in terms of inhibin B production to a 1 month FSH treatment. These patients were compared with three groups of patients affected by different spermatogenic alterations not related to deletions on the Y chromosome. RESULTS: Although affected by severe testiculopathy, patients with AZFc-DAZ deletions had only slightly elevated FSH, and normal inhibin B plasma concentrations. Inhibin B responded normally during FSH treatment, supporting the hypothesis that Sertoli cells are not altered. On the contrary, other severe testiculopathies not related to Y chromosome deletions showed high FSH and low inhibin B concentrations, with no response to FSH treatment. In these cases the cause of the spermatogenic defect probably damaged both germ and Sertoli cells. Finally, idiopathic patients with a hormonal status similar to Y-deleted patients (slightly elevated FSH and normal inhibin B concentrations) did not respond to FSH treatment, suggesting that Sertoli cells were already at their maximal functional capability. CONCLUSIONS: These data confirm that Sertoli cell function is not damaged in patients with AZFc-DAZ deletions and that the strong reduction of germ cells does not affect the FSH-inhibin B feedback loop.
Does GH replacement therapy in adult GH-deficient patients result in recurrence or increase in size of pituitary tumours?
Authors: Hatrick AG , Boghalo P , Bingham JB , Ayres AB , Sonksen PH , Russell-Jones DL
Published: January 2005

OBJECTIVE: Hypopituitary GH-deficient patients have an increased cardiovascular mortality and GH replacement in this population has resulted in considerable therapeutic benefit. GH replacement involves administration of a potentially mitogenic substance to patients with a previous or residual pituitary tumour. Our objective was to evaluate whether GH replacement results in an increase in the size of pituitary tumours. METHODS: This was a non-randomised observational study on patients recruited from the endocrine clinic. All subjects had GH deficiency, proven on an insulin tolerance test and were divided into those who were or were not receiving long-term GH replacement. Comparison of change in pituitary size was made with interval radiological imaging of the pituitary. RESULTS: Seventy-five patients (40 men and 35 women) were in the study, 47 were on long-term GH replacement and there were 28 controls. The average length of treatment for the treated group was 3.6 patient years. Thirty-nine patients in the treated group had at least 2 years of GH treatment between imaging studies of the pituitary. Two patients in the treated group had an increase in pituitary size (non-functioning adenomas) and two in the control group (one functioning and one non-functioning adenoma adenoma). None of these four patients required further treatment. There was no statistically significant difference between the two groups. CONCLUSION: Using a representative cohort of hypopituitary patients attending an endocrine clinic, GH replacement was not associated with an increased pituitary tumour recurrence rate. Although the results are not conclusive, in the period of observation GH had little adverse effect but longer studies are required to be certain.
IGF-I in human breast cancer: low differentiation stage is associated with decreased IGF-I content
Authors: Eppler E , Zapf J , Bailer N , Falkmer UG , Falkmer S , Reinecke M
Published: January 2005

OBJECTIVE: Few investigations on the potential role of IGF-I in human breast cancer have used morphological criteria, and the data presented on the localisation of IGF-I are controversial. Moreover, little information exists on a potential correlation between local IGF-I and the grade of malignancy or prognostic factors. Therefore, we investigated the immunohistochemical localisation of IGF-I in specimens of human breast cancer tumours of the ductal type, graded as G1/G2 (well-/moderately differentiated, n=115) and G3 (poorly differentiated, n=28). METHODS: IGF-I immunoreactivity was quantified using a scaling from no (-) to numerous (+++) IGF-I-immunoreactive cells. From 29 of the G1/G2 and 17 of the G3 tumours IGF-I was also measured by RIA. Cytosolic oestrogen receptor (ER) and progesterone receptor (PR) levels, and S-phase fraction were established and related to the number of IGF-I-immunoreactive cells. RESULTS: IGF-I immunoreactivity occurred predominantly in ductal epithelial cells. Of G3 tumours, 57% exhibited IGF-I immunoreactivity as compared with 84% of G1/G2 tumours. Correspondingly, the amount of IGF-I measured by RIA was significantly lower in G3 tumours (6.9+/-0.9 ng/g wet weight) than in G1/G2 tumours (10.5+/-1.1 ng/g wet weight) (P=0.031). G1/G2 tumours exhibited a higher percentage of IGF-I-immunoreactive cells (16% -, 23% +, 41% ++, 20% +++) than G3 tumours (43% -, 37% +, 12% ++, 8% +++). When comparing the - with the +++ G1/G2 tumours, the frequency of IGF-I-immunoreactive cells was related significantly to the ER (P<0.016) and the PR (P<0.008) levels. In G1/G2 and G3 tumours, the ER and PR levels increased with the amount of IGF immunoreactivity while the S-phase fraction increased with decreasing IGF-I content. In 25% of the specimens, IGF-I immunoreactivity occurred in stromal cells, but there was no obvious difference between the different types of tumours. The survival of the G1/G2 tumour patients increased with increasing numbers of IGF-I-immunoreactive cells. CONCLUSIONS: It is concluded that IGF-I is associated with the more-differentiated type of epithelial cells and that increasing dedifferentiation goes along with decreased IGF-I content. Thus, the presence of IGF-I immunoreactivity in breast cancer epithelial cells indicates a lower degree of malignancy than the lack of IGF-I.
IGF-I, IGF-II, 'free' IGF-I and IGF-binding proteins-2 to -6 during high-dose oestrogen treatment in constitutionally tall girls
Authors: Rooman RP , De Beeck LO , Martin M , Van Doorn J , Mohan S , Du Caju MV
Published: January 2005

OBJECTIVE: To investigate the effect of high-dose oestrogen treatment on IGF-I, IGF-II, free-dissociable IGF-I and the IGF-binding proteins (IGFBP)-2 to -6 in girls with constitutional tall stature. METHODS: In patient cohort 1, blood samples were drawn before and after 3 months of daily oral treatment with 0.1 mg ethinyloestradiol. In cohort 2, samples were collected at the end of the treatment period and 3 to 6 months afterwards. IGFs and IGFBPs were analysed by specific immunoassays and by Western ligand blot. RESULTS: Total IGF-I decreased significantly on oestrogen treatment and increased again after oestrogen withdrawal. Ligand blot analysis showed a clear reduction in a 34 kDa band, corresponding to IGFBP-2, and a strong induction of a 24 kDa band, corresponding to the non-glycosylated form of IGFBP-4. These changes were confirmed by specific immunological methods. The serum levels of IGFBP-3, IGFBP-5 and IGFBP-6 remained unchanged during the first 3 months of treatment. In cohort 2, IGFBP-3 and IGFBP-6 increased after oestrogen withdrawal. Free-dissociable IGF-I fell to 35+/-4% during oestrogen therapy and rose again when the treatment was stopped. CONCLUSIONS: Oestrogens modulate the serum concentrations of several components of the IGF system. The fall in total IGF-I is not explained by a decrease in IGFBPs but probably results from a decreased synthesis.
Prevalence of gestational diabetes mellitus: variations related to screening strategy used
Authors: Jimenez-Moleon JJ , Bueno-Cavanillas A , Luna-Del-Castillo JD , Garcia-Martin M , Lardelli-Claret P , Galvez-Vargas R
Published: January 2005

OBJECTIVE: To determine the prevalence of gestational diabetes mellitus in a large general obstetric population and its variations depending on the presence of risk factors, and to evaluate how the gestational diabetes screening strategies applied might modify the observed prevalence in the population. DESIGN: A retrospective cohort study. METHODS: The study population was a total of 2574 pregnant women. Information about risk factors, screening and diagnosis of gestational diabetes was obtained. Frequency of risk factors under the American College of Obstetrics and Gynecologists (ACOG) and the American Diabetes Association (ADA) criteria, and observed and expected prevalence of gestational diabetes mellitus were calculated and compared for statistical significance. RESULTS: Age > or = 30 years, family history of diabetes, obesity and previous fetal macrosomia were the most frequent risk factors. Under ACOG recommendations, 45% of our general obstetric population would have been exempt from gestational diabetes mellitus screening, as compared with only 15.5% under ADA guidelines. Sixty-five patients were diagnosed as having gestational diabetes mellitus, giving an overall prevalence of 2.5% (confidence interval 2.0-3.2). Among the low-risk women, prevalence values were 0.6% and 0.5% respectively under ACOG and ADA criteria, whereas for those presenting one or more risk factors rates were 4% and 2.9% respectively. CONCLUSIONS: In our general obstetric population, gestational diabetes mellitus prevalence was found to be approximately six times lower among low-risk gravidae than among the high-risk subjects, suggesting that selective screening might be beneficial. Nevertheless, selective gestational diabetes mellitus screening under ADA criteria seems to entail the same disadvantages as the selective screening strategies without any apparent benefits.
A pulse of insulin and dexamethasone stimulates serum leptin in fasting human subjects
Authors: Laferrere B , Caixas A , Fried SK , Bashore C , Kim J , Pi-Sunyer FX
Published: January 2005

OBJECTIVES: We have previously shown that dexamethasone increases serum leptin in fed but not in fasted human subjects. We hypothesized that insulin and/or glucose mediated the effect of food intake. The primary aim of this study was to determine whether the administration of a pulse of insulin with dexamethasone was sufficient to increase serum leptin in vivo in fasted human subjects. Whether the presence of transient hyperglycemia and the dose of insulin were important was tested as a secondary aim. METHODS: Twenty-nine normal subjects were studied. In experiment 1 (meal-like), a pulse of insulin (0.03 U/kg s.c.) and of dexamethasone (2 mg i.v.) was given, and the blood glucose transiently elevated to 50 mg/dl above baseline for the first 2 h. In experiments 2 and 3 (dose-response), the effect of two doses of insulin (0.03 U/kg in experiment 2 and 0.06 U/kg in experiment 3) was tested in combination with dexamethasone, this time without transient hyperglycemia. Nine subjects were studied under fasting conditions, with or without dexamethasone, as a control experiment. RESULTS: A meal-like transient hyperinsulinemia and hyperglycemia, with a pulse of dexamethasone, increased serum leptin levels from baseline by 54+/-21% at 9 h (P=0.038). In the absence of transient hyperglycemia, leptin increased significantly after doses of both insulin and dexamethasone. The effect of insulin was dose-dependent, with a larger increment of serum leptin at 9 h after the highest dose of insulin (75.2+/-15.7% vs 21.3+/-8.5%, P=0.013). Fasting, with or without dexamethasone, resulted in a significant 20% decrease in leptin from morning basal levels. Conversely, the administration of a pulse of insulin and glucose, in the absence of dexamethasone, prevented the drop in serum leptin observed during fasting, regardless of the insulin dose or the serum glucose elevation. CONCLUSIONS: With the permissive effect of dexamethasone, a single pulse of insulin triggered a rise in serum leptin in humans, even in the absence of transient hyperglycemia. A single pulse of insulin with glucose can prevent the drop in serum leptin normally observed during fasting.
Increased insulin sensitivity and decreased body weight in female rats after postnatal corticosterone exposure
Authors: Nilsson C , Jennische E , Ho HP , Eriksson E , Bjorntorp P , Holmang A
Published: January 2005

OBJECTIVE: Glucocorticoids are important for normal brain development. Elevation or removal of these hormones can permanently modify the structure and function of the fetal brain. The purpose of this study was to examine the effects of postnatal corticosterone exposure of female pups on metabolic, endocrine and anthropometric variables in adulthood. DESIGN: Female pups were given subcutaneous injections of corticosterone (5 mg/kg, CORT) or vehicle 3 and 5 days after birth. RESULTS: From 6 weeks of age, the CORT rats weighed significantly less than did controls, with diminished fat depots, decreased serum levels of leptin and reduced food intake. Adult CORT rats showed increased insulin sensitivity, measured by hyperinsulinemic, euglycemic clamp (5 mU/kg/min), as compared with controls. CORT rats had lower basal corticosterone levels and lower corticosterone levels 15 and 90 min after exposure to stress. CONCLUSION: The results indicate that postnatal exposure to corticosterone leads to increased insulin sensitivity, low body weight with diminished fat depots, leptin and food intake. This suggests that postnatal exposure to corticosterone induces specific programming, with consequences in adult life.
Bone effects of hexarelin, a GH-releasing peptide, in female rats: influence of estrogen milieu
Authors: Sibilia V , Cocchi D , Villa I , Lattuada N , Soglian A , Rubinacci A , Muller EE , Pecile A , Netti C
Published: January 2005

OBJECTIVE: The present study was performed to evaluate the potential influence of the estrogen milieu in modulating the effects of GH/IGF stimulation by a GH-releasing peptide, hexarelin (HEXA), on bone metabolism and mineral density in middle-aged female rats. METHODS: HEXA was administered for 60 days (50 microg/kg s.c. twice a day) to intact and ovariectomized (OVX) 11-month-old female rats and changes in bone parameters were evaluated with respect to those of the same rats under baseline conditions and with those of control rats (intact and OVX) administered isovolumetric amounts of physiological saline. Serum total alkaline phosphatase (ALP) and urinary deoxypyridinoline (Dpd) were measured before and at various times during HEXA treatment. Bone mineral content (BMC) and density of lumbar vertebrae and femoral mid-diaphyses were measured by dual energy X-ray absorptiometry before and after treatment. In all groups, serum IGF-I levels were determined before and during treatment and the GH secretory response to HEXA was assessed at the end of the experiment. RESULTS: In intact rats, HEXA did not modify Dpd urinary excretion, induced a trend toward an increase of serum ALP activity and significantly increased BMC (+6.5%) and bone area (+4.1%) only at lumbar vertebrae. In OVX rats, HEXA did not modify the OVX-induced increase in bone turnover markers (Dpd and ALP) and did not affect the OVX-induced vertebral bone loss, but significantly increased BMC (+7.2%) and bone area (+5.3%) at femoral mid-diaphyses. HEXA significantly increased serum IGF-I levels at day 14, but not at day 60, in both intact and OVX rats, whereas the GH secretory response to HEXA was higher in the former than in the latter. CONCLUSIONS: Overall, the present data demonstrate that chronic HEXA treatment increases BMC and bone area at lumbar vertebrae in intact rats and at femoral diaphyses in OVX rats. The different sensitivity to HEXA of the skeletal districts examined is related to the estrogen milieu and may reflect a complex interplay between estrogens and GH/IGF function.