bluuebunny/crossref_metadata_2025 huggingface dataset:
Somatotroph Tumor Progression during Pegvisomant Therapy: A Clinical and Molecular Study
Authors: Marazuela M. , Paniagua A. E. , Gahete M. D. , Lucas T. , Alvarez-Escolá C. , Manzanares R. , Cameselle-Teijeiro J. , Luque-Ramirez M. , Luque R. M. , Fernandez-Rodriguez E. , Castaño J. P. , Bernabeu I.
Published: January 2014

Context: There is concern that pegvisomant could be associated with a higher risk of tumor growth. The rate and possible determinants of this tumor growth are unknown.

Objective: The objective of the study was to investigate the clinical, immunohistological, and molecular factors conditioning tumor growth in patients taking pegvisomant.

Design and Setting: This was a cross-sectional study performed from 2004 to 2010 in four university hospitals in Spain.

Patients: Seventy-five acromegalic patients with active disease resistant to somatostatin analogs treated with pegvisomant were followed up for a mean of 29 ± 20 months.

Main Outcome Measures: Magnetic resonance images before initiation of pegvisomant, at 6 months, and then yearly were examined in all patients. Immunohistological and molecular studies were performed in tumors that grew.

Results: A significant increase in tumor size was observed in five patients (6.7%). Absence of previous irradiation (P = 0.014) and shorter duration of prepegvisomant somatostatin analog therapy (P < 0.001) were associated with an increased risk of tumor growth. A stepwise multivariate linear regression analysis (R2 = 0.334, P < 0.001) identified the duration of somatostatin analog therapy prior to pegvisomant (beta = −4.509, P = 0.014) as the only significant predictor of tumor growth. In those tumors that grew, GH expression and insulin receptor expression were higher (P = 0.033 in both cases) than in the control group.

Conclusions: No previous radiotherapy, shorter duration of prepegvisomant somatostatin analog therapy, and higher tumor expression of GH and insulin receptor could be risk factors for tumor growth during pegvisomant therapy.
Preconception Folic Acid Use Modulates Estradiol and Follicular Responses to Ovarian Stimulation
Authors: Twigt John M. , Hammiche Fatima , Sinclair Kevin D. , Beckers Nicole G. , Visser Jenny A. , Lindemans Jan , de Jong Frank H. , Laven Joop S. E. , Steegers-Theunissen Régine P.
Published: January 2014

Background: Folate is a methyl donor. Availability of folate affects DNA methylation profiles and thereby gene expression profiles. We investigated the effects of low-dose folic acid use (0.4 mg/d) on the ovarian response to mild and conventional ovarian stimulation in women.

Methods: In a randomized trial among subfertile women, 24 and 26 subjects received conventional and mild ovarian stimulation, respectively. Blood samples were taken during the early follicular phase of the cycle prior to treatment and on the day of human chorionic gonadotropin administration for determination of serum total homocysteine, anti-Müllerian hormone (AMH), estradiol, and folate. Folic acid use was validated by questionnaire and serum folate levels. Preovulatory follicles were visualized, counted, and diameters recorded using transvaginal ultrasound. The relation between folic acid use and ovarian response was assessed using linear regression analysis.

Results: Folic acid use modified the ovarian response to ovarian stimulation treatment. The estradiol response was higher in nonfolic acid users receiving conventional treatment [βinteraction = 0.52 (0.07–0.97); P = 0.03], and this effect was independent of serum AMH levels and the preovulatory follicle count. In the conventional treatment, the mean follicle number was also greater in nonusers compared with the users group (14.1 vs. 8.9, P = 0.03).

Conclusion: Low-dose folic acid use attenuates follicular and endocrine responses to conventional stimulation, independent of AMH and follicle count. The nature of this observation suggests that the effect of folic acid is most prominent during early follicle development, affecting immature follicles. Deleterious effects of folate deficiency, like DNA hypomethylation and oxidative stress, can help to explain our observations.
Action of Metformin on the Insulin-Signaling Pathway and on Glucose Transport in Human Granulosa Cells
Authors: Rice Suman , Pellatt Laura , Bryan Stacey , Whitehead Saffron Ann , Mason Helen Diane
Published: January 2014

This article appears in The Journal of Clinical Endocrinology & Metabolism, published January 5, 2011, 10.1210/jc.2010-2060
Angiotensin-Converting Enzyme Insertion/Deletion Polymorphism and Severe Hypoglycemia Complicating Type 2 Diabetes: The Fremantle Diabetes Study
Authors: Davis Wendy A. , Brown Simon G. A. , Jacobs Ian G. , Bulsara Max , Beilby John , Bruce David G. , Davis Timothy M. E.
Published: January 2014

Aims/Hypotheses:

The aims of this study were to determine whether the angiotensin-converting enzyme (ACE) gene I/D polymorphisms independently predict severe hypoglycemia in community-dwelling type 2 patients.

Methods:

Six hundred two patients who were ACE genotyped at baseline and assessed in 1998 were followed up to the end of June 2006. Severe hypoglycemia was defined as that requiring documented health service use as the primary diagnosis. Cox proportional hazards modeling was used to determine the predictors of first episode and zero-inflated negative binomial regression modeling identified predictors of frequency.

Results:

Forty-nine patients (8.1%) experienced 63 episodes of severe hypoglycemia. After adjusting for previously identified significant independent predictors of time to first episode, both ACE DD genotype and ACE inhibitor therapy, but not their interaction, added to the model [hazard ratio (95% confidence interval): 2.34 (1.29–4.26), P = 0.006, and 1.77 (0.99–3.13), P = 0.052, respectively]. Similarly, after adjusting for previously identified risk factors for multiple episodes of severe hypoglycemia, ACE DD genotype was independently associated with increased risk [incidence relative risk (95% confidence interval): 1.80 (1.00–3.24), P = 0.050].

Conclusions/Interpretation:

ACE DD genotype is associated with an increased the risk of the first episode of severe hypoglycemia and its subsequent frequency approximately 2-fold in well-characterized patients with type 2 diabetes. Consistent with previous case-control studies, ACE inhibitor therapy was a weak predictor of severe hypoglycemia. ACE I/D genotyping might provide useful adjunctive prognostic information when intensive glycemic control measures are contemplated.
Using Dilution Techniques and Multifrequency Bioelectrical Impedance to Assess Both Total Body Water and Extracellular Water at Baseline and During Recombinant Human Growth Hormone (GH) Treatment in GH-Deficient Adults*
Authors: Janssen Y. J. H. , Deurenberg P. , Roelfsema F.
Published: January 2014

Due to the use of various, and mostly indirect, methods to estimate total body water (TBW) and extracellular water (ECW), there is no agreement about whether body water distribution, i.e. the ECW to TBW ratio, is normal in GH-deficient (GHD) subjects at baseline and during recombinant human GH (rhGH) treatment. We studied body water distribution in 14 patients with adult-onset GHD and in 28 healthy controls. We also investigated the effect of GH replacement therapy for 4 and 52 weeks on body water distribution. All patients started with a dose of 0.6 IU rhGH/day for the first 4 weeks. After 52 weeks, the dose varied between 0.6–1.8 IU/day. TBW and ECW were measured by dilution of deuterium and bromide, respectively. Both parameters were also estimated using multifrequency bioelectrical impedance (BIA).

Patients with GHD had significantly lower ECW and TBW than healthy controls. In addition, the ECW to TBW ratio was significantly lower in GHD patients than in healthy controls. Four weeks of GH treatment significantly increased body weight, TBW, ECW, and ECW/TBW. A further increase in TBW, but not ECW, was found after 52 weeks of treatment. The mean increases in TBW and ECW from the baselines were 2.5 ± 0.3 and 2.0 ± 0.3 L, respectively.

The correlation coefficient and the estimated reliability between measured and estimated TBW and ECW at any time point were all high (>0.91 and >0.95, respectively). In general, both ECW and TBW were overestimated by multifrequency BIA in GHD adults. During treatment, the overestimation of both ECW and TBW diminished. The estimation error was correlated with the level of the body water compartment and the ratio of ECW to TBW. The estimated change in ECW with rhGH treatment was underestimated by multifrequency BIA.

We conclude that GHD adults have lower ECW and TBW and a lower ECW to TBW ratio, as measured by dilution techniques. The ECW to TBW ratio can be normalized within 4 weeks of rhGH treatment at a dose of 0.6 IU/day. Finally, we conclude that multifrequency impedance measurements do not give valid estimates of body water compartments in the follow-up of patients with GHD.
Evaluation of the Dexamethasone Suppression Test for the Diagnosis of Glucocorticoid-Remediable Aldosteronism1
Authors: Litchfield W. Reid , New Maria I. , Coolidge Caroline , Lifton Richard P. , Dluhy Robert G.
Published: January 2014

Glucocorticoid-remediable aldosteronism (GRA) is a rare form of inherited hypertension caused by a characteristic gene duplication. With the advent of definitive genetic testing for GRA, the performance of the traditional screening test for GRA, the dexamethasone suppression test (DST), can be evaluated. We compared the DST to direct genetic testing in 24 patients referred for genetic screening for GRA (12 GRA positive and 12 GRA negative) based on clinical and biochemical findings, DST, and family history. Plasma aldosterone was measured before and after oral dexamethasone administration to determine the extent to which aldosterone was suppressed by glucocorticoids in each patient group. The results of the DST in these subjects were also compared to those in 19 historical patients with primary aldosteronism[ 4 bilateral hyperplasia and 15 aldosterone-producing adenoma (APA)] reported previously. The DST differentiated GRA-positive from GRA-negative patients with 92% sensitivity and 100% specificity. Cutoffs based on the post-DST plasma aldosterone level (<4 ng/dL) or percent suppression compared to baseline (>80%) were equally effective in correctly diagnosing GRA (only one GRA-positive patient would have been incorrectly diagnosed). However, DST in 15 APA patients revealed that 33% had greater than 80% suppression of aldosterone, and 1 had aldosterone levels below 4 ng/dL.

We conclued that a post-DST aldosterone level below 4 ng/dL will correctly diagnose GRA patients with high sensitivity and specificity. Suppression compared to baseline can be misleading, as evidenced by the results in APA patients and referred subjects who genetically screened negative.
A Homozygous Missense Mutation of the Sodium/Iodide Symporter Gene Causing Iodide Transport Defect1
Authors: Matsuda Akira , Kosugi Shinji
Published: January 2014

Iodide transport defect is a disorder characterized by an inability of the thyroid to maintain an iodide concentration difference between the plasma and the thyroid. The recent cloning of the sodium/iodide symporter (NIS) gene enabled us to characterize the NIS gene in this disorder. We identified a homozygous missense mutation of A→C at nucleotide +1060 in NIS complementary DNA in a male patient who was born from consanguineous marriage, had a huge goiter, and lacked the ability to accumulate iodide but was essentially euthyroid. The mutation results in an amino acid replacement of Thr354→Pro in the middle of the ninth transmembrane domain. COS-7 cells transfected with the mutant NIS complementary DNA showed markedly decreased iodide uptake, confirming that this mutation was the direct cause of the disorder in the patient. Northern analysis of thyroid ribonucleic acid revealed that NIS messenger ribonucleic acid level was markedly increased (>100-fold) compared with that in the normal thyroid, suggesting possible compensation by overexpression.
Characterization of Monoclonal Thyroid-Stimulating and Thyrotropin Binding-Inhibiting Autoantibodies from a Hashimoto’s Patient Whose Children Had Intrauterine and Neonatal Thyroid Disease
Authors: Kohn Leonard D. , Suzuki Koichi , Hoffman William H. , Tombaccini Donatella , Marcocci Claudio , Shimojo Naoki , Watanabe Yukihiko , Amino Nobuyuki , Cho Bo Youn , Kohno Yoichi , Hirai Aizan , Tahara Kazuo
Published: January 2014

A multiplicity of TSH receptor autoantibodies (TSHRAbs) have been characterized after subcloning heterohybridomas produced from the lymphocytes of a patient who has Hashimoto’s thyroiditis and had three children with intrauterine or neonatal hyperthyroidism. Twelve clones produced stimulating TSHRAbs that increased cAMP levels and iodide uptake in rat FRTL-5 thyroid cells and increased cAMP levels in Chinese hamster ovary (CHO) cells transfected with the human TSHR; like 95% of Graves’ stimulating TSHRAbs, all 12 have their functional epitope on the N-terminus of the TSHR extracellular domain, requiring residues 90–165 for activity. All 12 bind to human thyroid membranes in the absence, but not the presence, of TSH, but are only weak inhibitors of TSH binding in assays measuring TSH binding-inhibiting Igs (TBIIs). In contrast, 8 different clones produced TSHRAbs that did not increase cAMP levels, but, instead, exhibited significant TBII activity. Four inhibited the ability of TSH or a stimulating TSHRAb to increase cAMP levels and had their functional epitope on the C-terminal portion of the TSHR external domain, residues 261–370, mimicking the properties of blocking TSHRAbs that cause hypothyroidism in patients with idiopathic myxedema. The 4 other TBIIs inhibited the ability of TSH, but not that of a stimulating TSHRAb, to increase cAMP levels, like TBIIs in Graves’ patients. The functional epitope for 3 of these Graves’-like TBIIs was residues 90–165; the functional epitope for the fourth was residues 24–89. The fourth also increased arachidonic acid release and inositol phosphate levels in FRTL-5 thyroid cells and exhibited conversion activity, i.e. the ability to increase cAMP levels in the presence of an anti-human IgG. Thus, this TBII exhibited signal transduction activity, unlike the other 3 Graves’-like TBIIs. The patient, therefore, has stimulating TSHRAbs and 3 different types of TBIIs, each with different functional properties and different epitopes on the TSHR.
Stimulation of Mitochondrial Fatty Acid Oxidation by Growth Hormone in Human Fibroblasts1
Authors: Leung Kin-Chuen , Ho Ken K. Y.
Published: January 2014

In vivo administration of GH induces lipolysis and lipid oxidation. However, it is not clear whether the stimulation of lipid oxidation is a direct effect of GH or is driven by increased substrate supply secondary to lipolysis. An in vitro bioassay has been established for assessing β-oxidation of fatty acids in mitochondria, based on the measurement of conversion of tritiated palmitic acid to 3H2O by fibroblasts in culture. We have modified this assay to investigate whether GH stimulates fatty acid oxidation.

GH stimulated oxidation of palmitic acid maximally by 26.7 ± 2.5% (mean ± sem; P < 0.0001). The stimulation was biphasic, with the oxidation rate increasing with increasing GH concentration to a peak response at 1.5 nmol/L and declining to a level not significantly different from control thereafter. Insulin-like growth factor-I at concentrations of up to 250 nmol/L had no significant effect on fatty acid oxidation. GH-binding protein attenuated the effect of GH. An anti-GH receptor (GHR) antibody (MAb263), which dimerizes the receptor and induces GH-like biological actions, significantly stimulated fatty acid oxidation. Another anti-GHR antibody (MAb5), which prevents receptor dimerization, suppressed GH action. In summary, GH directly stimulated fatty acid oxidation, an action not mediated by insulin-like growth factor-I. Dimerization of GHRs was necessary for this effect. This bioassay is a practical tool for studying the regulatory effects of GH on lipid oxidation.
Leptin Synthesis Is Resistant to Acute Effects of Insulin in Insulin-Dependent Diabetes Mellitus Patients*
Authors: Tuominen Juha A. , Ebeling Pertti , Stenman Ulf-Håkan , Heiman Mark L. , Stephens Thomas W. , Koivisto Veikko A.
Published: January 2014

Insulin stimulates ob gene expression and increases serum leptin concentrations in mice and in noninsulin-dependent diabetes mellitus patients. Obese women have higher ob gene messenger ribonucleic acid levels than obese men, suggesting that sex hormones are involved in the regulation of leptin synthesis. We studied the relationship among leptin, insulin, and testosterone in 15 men with insulin-dependent diabetes mellitus (IDDM; age, 29 ± 2 yr; body mass index, 22.7 ± 0.5 kg/m2; body fat, 9.5 ± 1.0%; insulin dose, 44 ± 4 U/day; hemoglobin A1c, 8.1 ± 0.3%; diabetes duration, 12.7 ± 2.0 yr) and 15 healthy control subjects (age, 27 ± 1 yr; body mass index, 22.6 ± 0.4 kg/m2; body fat, 9.6 ± 0.5%) in the fasting state. In addition, the effect of a 4-h euglycemic hyperinsulinemia (∼600 pmol/L) on the plasma leptin concentration was determined. The fasting leptin concentration was negatively correlated to plasma testosterone (r = −0.55; P < 0.05) in IDDM patients. The fasting plasma leptin level rose 25% in healthy subjects (from 1.0 ± 0.2 to 1.3 ± 0.3 ng/mL; P < 0.05). The leptin levels were higher in IDDM subjects (P < 0.01) and remained unchanged (2.7 ± 0.2 vs. 2.7 ± 0.2 ng/mL) during hyperinsulinemia.

We reached the following conclusions. 1) In nonobese IDDM patients, leptin synthesis is resistant to the acute effect of insulin. 2) Serum testosterone may contribute to the regulation of leptin synthesis in IDDM patients.
Suppression of Growth Hormone (GH) Hypersecretion due to Ectopic GH-Releasing Hormone (GHRH) by a Selective GHRH Antagonist*
Authors: Jaffe Craig A. , DeMott-Friberg Roberta , Frohman Lawrence A. , Barkan Ariel L.
Published: January 2014

We have recently demonstrated that a competitive antagonist of GHRH, (N-Ac-Tyr1,d-Arg2)GHRH-(1–29)NH2 (GHRH-Ant), eliminates nearly all nocturnal GH pulsatility in normal subjects, supporting the hypothesis that GH pulsatility is driven by GHRH. In this study, we compared the effects of every 12 h iv boluses of either GHRH-Ant or saline on 24-h GH profiles in a patient with acromegaly due to a metastatic GHRH-secreting carcinoid tumor. Bolus doses of GHRH-Ant (400 μg/kg, iv) acutely suppressed GH concentration to 30–40% of the pretreatment baseline, and this effect lasted 3–4 h. Administration of GHRH (0.33 μg/kg, iv) bolus resulted in a small rise in GH, and this effect was blocked by GHRH-Ant (400μ g/kg). During saline treatment, the secretory patterns of both GH and ectopic GHRH were pulsatile; however, there was no correlation between changes in plasma GHRH and GH concentrations. This lack of correlation was probably due to the majority of circulating GHRH immunoreactivity consisting of nonbiologically active GHRH fragments. These data support the hypothesis that GH hypersecretion in the ectopic GHRH syndrome requires GHRH receptor occupancy and validates the use of GHRH-Ant to probe the potential involvement of endogenous GHRH in patients with acromegaly due to pituitary somatotropinoma.
Diurnal Variations in Twenty-Four-Hour Energy Expenditure During Growth Hormone Treatment of Adults with Pituitary Deficiency*
Authors: Stenlöf Kaj , Johansson Jan-Ove , Lönn Lars , Sjöström Lars , Bengtsson Bengt-Åke
Published: January 2014

The effects of growth hormone (GH) treatment on 24-h energy expenditure (EE) were studied in a open trial over a period of 4 weeks. Five subjects, four men and one woman, with a history of complete GH deficiency were included. All the subjects were examined on 2 consecutive days on baseline and, thereafter, at six occasions during a period of 1 month (days 1, 2, 5, 8, 15, and 30). The dose of GH was 0.25 U/kg·week, administered sc once a day in the evening.

EE was determined in a chamber for indirect calorimetry. Body composition was determined with dual-energy x-ray absorptiometry and computed tomography using a four-scan technique. Blood samples were examined using well-established RIAs.

During the first 2 weeks, 24-h EE increased by 6 ± 3% (range 1–8%) from 40.9 ± 4.8 to 42.9 ± 4.8 kcal/24 h·kg (P < 0.05), sleeping metabolic rate by 14 ± 3% (range 10–18%) from 28.4 ± 1.9 to 32.9 ± 2.2 kcal/24h·kg (P < 0.001), and basal metabolic rate by 11 ± 7% (range 0–18%) from 29.6 ± 2.4 to 33.3 ± 2.6 kcal/24h·kg (P < 0.05). No change was found in daytime EE. The increase in EE covaried with changes in insulin-like growth factor 1, the free T3/free T4 ratio, insulin-like growth factor-binding protein-3, and the aminoterminal procollagen III peptide but not with changes in body composition.

It is suggested that the stimulating effect of GH on EE occurs gradually during a 2-week period and is only detectable during night and morning hours, when significant levels of GH occur.
Blocking of Central Nervous Mineralocorticoid Receptors Counteracts Inhibition of Pituitary-Adrenal Activity in Human Sleep*
Authors: Born Jan , Steinbach Dirk , Dodt Christoph , Fehm Horst-Lorenz
Published: January 2014

Pituitary-adrenal activity has been found to be inhibited during early nocturnal sleep in humans. This inhibition was supposed to reflect a regulatory influence of hippocampal cells characterized by the expression of mineralocorticoid receptors (MR). Pituitary adrenal responsiveness to bolus injections of CRH (50 μg) was examined in each of nine healthy men on four occasions: CRH was injected either during early nocturnal sleep or at the same time of night while the subject was kept awake. Both of these conditions were run after pretreatment with the selective MR antagonist, canrenoate (2 × 200 mg, 0800 and 1700 h, preceding the experimental night) and after placebo administration. After placebo, sleep reduced ACTH and cortisol secretory responses to CRH to about 65% of the size observed during wakefulness (P < 0.05). After canrenoate, ACTH and cortisol secretory responses during sleep and wakefulness did not differ and were comparable with those obtained in placebo-treated subjects during wakefulness. Compared with placebo, canrenoate also distinctly reduced the time spent in slow-wave sleep (P < 0.005). The findings confirm an inhibition of pituitary-adrenal responsiveness during early sleep. The inhibition disappearance after blockage of MR suggests that sleep exerts this influence via central nervous MR-expressing cells. These cells seem to be simultaneously involved in the generation of slow-wave sleep.
Liddle’s Syndrome: Prospective Genetic Screening and Suppressed Aldosterone Secretion in an Extended Kindred*
Authors: Findling James W. , Raff Hershel , Hansson Joni H. , Lifton Richard P.
Published: January 2014

Liddle’s syndrome is an autosomal dominant form of hypertension that resembles primary hyperaldosteronism, is characterized by the early onset of hypertension with hypokalemia and suppression of both PRA and aldosterone, and is caused by mutations in the carboxyl-terminus of theβ - or γ-subunits of the renal epithelial sodium channel. We describe a kindred (K176) whose distinguishing clinical features were mild hypertension and decreased aldosterone secretion. The index case was a 16-yr-old girl with intermittent mild hypertension and hypokalemia and subnormal PRA, aldosterone, 18-hydroxycorticosterone, and deoxycortisol levels, but normal cortisol/cortisone metabolite ratio and cortisol half-life. A frameshift mutation in the carboxyl-terminus of the β-subunit of the epithelial sodium channel was identified in the index case, establishing the diagnosis of Liddle’s syndrome. Sixteen at-risk relatives of the index case were tested. Seven new subjects were heterozygous for the mutation found in the index case, and two deceased obligate carriers were identified. All genetically affected adult subjects had a history of mild hypertension, and four had a history of hypokalemia. Basal and postcosyntropin plasma aldosterone and urinary aldosterone levels were significantly suppressed in those positive for the mutation. The family demonstrates variability in the severity of hypertension and hypokalemia in this disease, raising the possibility that this disease may be underdiagnosed among patients with essential hypertension.
Lack of Association between the Trp64Arg Mutation in the β3-Adrenergic Receptor Gene and Obesity in Japanese Men: A Longitudinal Analysis
Authors: Nagase Terumasa , Aoki Akira , Yamamoto Michiko , Yasuda Hiroko , Kado Seijiro , Nishikawa Miyuki , Kugai Nobuo , Akatsu Takuhiko , Nagata Naokazu
Published: January 2014

The β3-adrenergic receptor (β3AR) is implicated in the regulation of thermogenesis and lipolysis, and it is suggested that the Trp64Arg mutation in this receptor may contribute to the development of obesity. To examine whether the Trp64Arg mutation had any effect on body weight during adult life, the β3AR genotype was determined in 186 unselected Japanese men, most of whom had records of body weight measured yearly from 25–53 yr of age. Of them, 26 subjects were diagnosed as having noninsulin-dependent diabetes mellitus (NIDDM) and 41 as having impaired glucose tolerance. There were 6 subjects (3%) with homozygous mutation, 67 (36%) with heterozygous mutation, and 113 (61%) with normal allele. Among the 3 genotypes, there were no significant differences in body mass index (BMI) at any age between 25–53 yr and the prevalence of NIDDM at the age of 53 yr. When longitudinal changes in body weight were compared between subjects with and without mutation, the former were less prone to gain weight than the latter. The frequency of the mutant allele was 1) not different among obese (BMI, >26.4), intermediate (BMI, 22–26.4), and nonobese (BMI, <22.0) subjects (0.21, 0.22, and 0.26, respectively; P = 0.77); 2) lower in subjects with NIDDM than in those without it, but the difference was insignificant (0.12 vs. 0.23; P = 0.07); and 3) similar between 186 unselected men and another group of 100 patients with NIDDM that were randomly selected for comparison (0.21 vs. 0.23). These results suggest that the β3AR is not a major contributing factor to obesity or NIDDM in Japanese men.
Loss of Heterozygosity at 11q13: Analysis of Pituitary Tumors, Lung Carcinoids, Lipomas, and Other Uncommon Tumors in Subjects with Familial Multiple Endocrine Neoplasia Type 1
Authors: Dong Qihan , Debelenko Larisa V. , Chandrasekharappa Settara C. , Emmert-Buck Michael R. , Zhuang Zhengping , Guru Siradanahalli C. , Manickam Pachiappan , Skarulis Monica , Lubensky Irina A. , Liotta Lance A. , Collins Francis S. , Marx Stephen J. , Spiegel Allen M.
Published: January 2014

Loss of heterozygosity (LOH) for polymorphic markers flanking the multiple endocrine neoplasia type 1 (MEN-1) gene in parathyroid and pancreatic islet tumors from subjects with familial MEN-1 (FMEN-1) has been well documented and has led to the hypothesis that the MEN-1 gene functions as a tumor suppressor. To assess the role of the MEN-1 gene in the pathogenesis of tumors less commonly associated with MEN-1, we employed a large number of highly informative polymorphic markers closely linked to the MEN-1 gene to study a series of 13 such tumors from subjects with FMEN-1 for LOH at 11q13. We were able to identify LOH for 1 or more 11q13 markers in 2 of 3 pituitary tumors, 3 lung carcinoids, and 1 of 2 lipomas. In every case studied, the allele lost represented the normal allele inherited from the unaffected parent. No LOH was detected in 3 skin angiofibromas, an esophageal leiomyoma, or a renal angiomyolipoma despite the presence of at least 2 informative markers for each tumor. Our results suggest that, like that for parathyroid and pancreatic islet tumors, the pathogenesis of pituitary tumors, lung carcinoids, and lipomas occurring in subjects with FMEN-1 probably involves loss of the normal tumor suppressor function of the MEN-1 gene. Our inability to detect 11q13 LOH in skin angiofibromas, leiomyoma, and angiomyolipoma from subjects with FMEN-1 is consistent with the possibility that these neoplasms arose independently by a mechanism unrelated to the MEN-1 gene, but a role for the MEN-1 gene in the pathogenesis of these tumors cannot be definitively excluded until the gene itself is identified and evaluated for small intragenic deletions or point mutations in such tumors.
Assessment of Androgen Receptor Function in Genital Skin Fibroblasts Using a Recombinant Adenovirus to Deliver an Androgen-Responsive Reporter Gene1
Authors: McPhaul Michael J. , Schweikert Hans-Udo , Allman Diane R.
Published: January 2014

Mutations of the androgen receptor (AR) cause defects in virilization and can result in a spectrum of phenotypic abnormalities of male sexual development that includes patients with a completely female phenotype (complete testicular feminization) and individuals with less severe defects of virilization, such as Reifenstein syndrome. These phenotypes are not specific for mutations of the AR gene, however, and defects in other genes can also result in similar abnormalities of male development. For this reason, the diagnosis of an AR defect is laborious and requires data from endocrine studies, the family history, and in vitro binding experiments.

To assist in the evaluation of patients with possible AR defects, we previously employed the use of a recombinant adenovirus to deliver an androgen-responsive gene into fibroblast cultures to assay AR function in normal subjects and patients with complete forms of androgen resistance. Although these studies demonstrated measurable differences between these two groups of subjects, we did not assay samples from patients with partial defects of androgen action. In the current study, we have modified this method to examine AR function in three groups of patients with known or suspected defects of AR function: patients with Reifenstein syndrome, patients with spinobulbar muscular atrophy, and patients with severe forms of isolated hypospadias. When assayed using this method, the AR function of patients with Reifenstein syndrome was intermediate between that of normal control subjects and that of patients with complete testicular feminization. Using the parameters established by the aforementioned experiments, we found that defective AR function can be detected in fibroblasts established from patients with spinobulbar muscular atrophy and in some patients with severe forms of isolated hypospadias, including two with a normal AR gene sequence. These results suggest that this method may have some utility in screening samples to detect defects of AR function, particularly when viewed in the context of other AR assays results.
Alterations in the Glucose-Stimulated Insulin Secretory Dose-Response Curve and in Insulin Clearance in Nondiabetic Insulin-Resistant Individuals
Authors: Jones Clare N. O. , Pei Dee , Staris Patricia , Polonsky Kenneth S. , Chen Y. D.-Ida , Reaven Gerald M.
Published: January 2014

Plasma glucose and insulin responses to a graded iv infusion of glucose were compared in two groups of glucose-tolerant women divided on the basis of their insulin sensitivity. Resistance to insulin-mediated glucose disposal was measured using the insulin suppression test, and the women studied were chosen to represent the highest and lowest quartiles of insulin resistance seen in the normal population. The sensitivity of the pancreatic β-cell to glucose was assessed by measuring the glucose, insulin, and C peptide concentrations in response to continuous graded iv infusions of glucose at rates of 1, 2, 3, 4, 6, and 8 mg/kg·min for 40 min each. In addition, insulin secretion rates in response to the graded glucose infusion, calculated over each sampling period, were derived from deconvolution of peripheral plasma C peptide concentrations, using a two-compartment model of C peptide kinetics and standard parameters for C peptide clearance. Although plasma glucose concentrations were only slightly higher throughout the glucose infusion, the insulin concentrations were approximately doubled in the insulin-resistant subjects. When expressed as a function of the molar increments in plasma glucose achieved during the glucose infusion studies, the insulin-resistant women had a 90% higher (684 ± 55 vs. 360 ± 36 pmol/L·mmol/L; P < 0.001) total integrated plasma insulin response as the glucose concentration was increased from 5 to 9 mmol/L. However, the total integrated insulin secretory rate was only increased by 37% (1494 ± 133 vs. 1093 ± 125 pmol/mmol/L·min; P < 0.05) in the insulin-resistant group. This discrepancy suggested that insulin clearance was lower in the insulin-resistant subjects, and the calculation of this value, as the ratio of the total secretion of insulin to the area under the plasma insulin curve, was significantly lower in the insulin-resistant group (1.25 ± 0.05 vs. 1.87 ± 0.16 L/min·m2; P < 0.005). These results show that the hyperinsulinemia of insulin resistance results from an increase in insulin secretion secondary to a shift to the left of the glucose-stimulated insulin response curve as well as a decrease in insulin clearance.
Predictors of Early Remission of Hyperthyroidism in Children1
Authors: Glaser Nicole S. , Styne Dennis M.
Published: January 2014

Children with hyperthyroidism often require prolonged courses of antithyroid medication to achieve remission, and long-term compliance is problematic. To determine which clinical and laboratory features predict early remission, we reviewed the records of 191 patients less than 19 yr old with Graves’ disease. We compared patients achieving remission within 2 yr (group 1, n = 27) with those who completed more than 2 yr of medical therapy but did not achieve a remission (group 2, n = 79). Patients who were in neither of the above categories (n = 85) were excluded from the statistical analysis. Variables that were measurable at the time of diagnosis, recorded in more than 50% of the study population and associated with early remission in the univariate analysis (P ≤ 0.05), were entered into a stepwise multiple logistic regression analysis. Variables retaining a significant association with early remission (P < 0.05) were considered independent predictors of early remission. Patients achieving early remission were older (mean, 12.5 vs. 10.9 yr, P = 0.039) and had higher body mass indexes (BMI, 19.0 vs. 16.6, P = 0.002), higher BMI sd scores (−0.03 vs. −0.60, P = 0.004), lower heart rates (110 vs. 121, P = 0.023), smaller goiters (group 1: 60% with moderate/large goiter; group 2: 83%, P = 0.050), lower platelet counts (272 vs. 339 K/μL, P = 0.006), lower serum T4 and T3 concentrations at presentation (T4: 18.3 vs. 22.5 μg/dL, P = 0.015; T3: 439 vs. 613 ng/dL, P = 0.008), and were less likely to have a positive test for thyroid stimulating Igs (group 1: 50% vs. group 2: 93%, P = 0.008). Regression analysis identified BMI sd score and goiter size as independent predictors of early remission (P < 0.05). Eighty-six percent of patients with BMI sd score above −0.5 sd and minimal/small goiters achieved early remission, compared with 13% of those with BMI sd score below −0.5 sd and moderate/large goiters. We conclude that, of multiple clinical and laboratory variables associated with early remission, BMI sd score and goiter size are independent predictors. Algorithms employing these two variables can be used to facilitate counseling of patients and expedite therapeutic decisions.
The Predictive Value of Biochemical Markers of Bone Turnover for Bone Mineral Density in Early Postmenopausal Women Treated with Hormone Replacement or Calcium Supplementation1
Authors: Rosen Clifford J. , Chesnut Charles H. , Mallinak Nancy J. S.
Published: January 2014

To compare the relative sensitivity and specificity of bone turnover indexes for bone loss or gain in early postmenopausal women, we performed a multicenter trial in 236 menopausal women (mean age, 51 yr), who were randomized to hormone replacement therapy (HRT) or calcium supplementation (CS; 500 mg/day) for 1 yr. Two markers of bone formation, osteocalcin (OC) and bone alkaline phosphatase (BSAP), and two markers of bone resorption, urinary N-telopeptide (NTx) and urinary free deoxypyridinoline (fDpd), as well as spine and femoral neck bone mineral density (BMD) were measured at baseline and 3, 6, and 12 months after treatment. Women receiving HRT (n = 105) showed a significant increase in spine BMD (+2.5%; P < 0.0001) and hip BMD (+1.0%; P = 0.02) compared to women receiving CS, who showed a decline at both sites (−1.1%; P < 0.01). All four markers showed time-dependent decreases in women receiving HRT (P < 0.001) and no change in women receiving CS alone. When baseline indexes of turnover were stratified by quartile, there was a significantly greater increase in BMD among those with the highest NTx, OC, and BSAP levels compared to that in those with the lowest NTx, OC, and BSAP levels (P < 0.05). The highest quartile for percent change from baseline to 6 months in fDpd, BSAP, and NTx was also associated with the greatest change in spine BMD at 1 yr. Receiver operator characteristic curves for percent change from baseline to 6 months in an individual marker to 1 yr change in BMD during HRT revealed that the percent change in NTx provided the greatest discrimination between gain and loss of BMD. When subjects receiving HRT were compared by their positive or negative skeletal response at 1 yr and their baseline turnover marker, initial NTx values were significantly higher in those that gained bone than in those that lost bone (P = 0.0002). CS women in the highest quartile for NTx at baseline had significantly greater decreases in spine BMD than subjects with the lowest NTx values (P < 0.005), although this was not true for fDpd (P < 0.20). In conclusion, for early postmenopausal women there are differential responses of biochemical markers to HRT and CS. Baseline urinary NTx and serum OC were the most sensitive predictors of change in spine BMD after 1 yr of either HRT or CS. Similarly, the percent change in NTx and OC from baseline to 6 months best predicted bone gain or loss. We conclude that markers of bone formation and resorption can be used clinically to predict future BMD in early postmenopausal women.
Testing the Hypothalamic-Pituitary-Adrenal Axis in Survivors of Childhood Brain and Skull-Based Tumors1
Authors: Shankar R. Ravi , Jakacki Regina I. , Haider Anzar , Lee Melissa W. , Pescovitz Ora Hirsch
Published: January 2014

The objective of this study was to determine whether a low dose of ACTH (0.2 μg/kg) improves the sensitivity of ACTH testing in detecting hypothalamic-pituitary-adrenal (HPA) axis abnormalities in survivors of childhood brain and skull-based tumors.

Twenty-two children who had undergone treatment for brain or skull-based tumors were enrolled in a prospective study to extensively evaluate the HPA axis. Five tests of the adrenal axis were evaluated in each patient, including determination of basal serum cortisol, a standard ACTH test (250-μg iv bolus), a low dose ACTH test (0.2μ g/kg iv bolus), an insulin tolerance test, and a single dose metyrapone test.

Cortisol responses to both ACTH tests were nearly identical. Two patients (9%) failed the low dose ACTH test, whereas three (14%) failed the standard ACTH test; five of the children (23%) failed the insulin tolerance test, and five (23%) had abnormal responses to metyrapone. One child who initially passed the metyrapone test failed the test 19 months later after becoming symptomatic. All children with abnormal metyrapone test results had low levels of basal cortisol secretion.

In this study, the low dose ACTH test did not improve the sensitivity of ACTH testing for evaluation of the HPA axis. We conclude that a single morning basal cortisol level is a good screen for testing the HPA axis in children. We recommend confirming HPA axis dysfunction with the single dose metyrapone test, although this test also has limitations.
Differential Gene Expression of Steroid 5α-Reductase 2 in Core Needle Biopsies from Malignant and Benign Prostatic Tissue1
Authors: Bjelfman Catarina , Söderström Torbjörn G. , Brekkan Einar , Norlén Bo Johan , Egevad Lars , Unge Torsten , Andersson Stefan , Rane Anders
Published: January 2014

Androgens are implicated in the development of prostate cancer (CAP) and benign prostate hyperplasia. The conversion of testosterone to the more potent metabolite dihydrotestosterone by prostate-specific steroid 5α-reductase type 2 (5α-red2) is a key mechanism in the action of androgens in the prostate and is important in the promotion and progression of prostate diseases. Manipulation of the turnover of androgens is thus fundamental in the pharmacological treatment strategy.

We have developed a sensitive solution hybridization method for quantification of the gene expression of 5α-red2 in core needle biopsies of the prostate. The 5α-red2-specific messenger RNA (mRNA) levels were measured in 50 human prostate transrectal ultrasound-guided core biopsies obtained from 31 outpatients (median age 72, range 57–88 yr) undergoing biopsy for diagnostic purposes. Significant differences were observed in the gene expression of 5α-red2 between cancerous and noncancerous tissue. In the 14 biopsies judged cancerous, the median 5α-red mRNA levels were 3.5 amol/ng total RNA compared with 12.0 amol/ng total RNA in the biopsies showing no cancer (P = 0.0018). The median 5α-red2 mRNA level in noncancerous tissue was thus 3.4 times higher than in the cancerous specimens.
The Human Thyrotropin (TSH) Receptor in a TSH Binding Inhibition Assay for TSH Receptor Autoantibodies1
Authors: Kakinuma Ayumu , Chazenbalk Gregorio D. , Jaume Juan Carlos , Rapoport Basil , McLachlan Sandra M.
Published: January 2014

Seven years after the molecular cloning of the human TSH receptor (TSHR), the porcine TSHR remains in general use in the TSH binding inhibition (TBI) assay for autoantibodies to the TSHR. We compared porcine and recombinant human TSHR in two types of TBI assays: one using intact Chinese hamster ovary cells expressing the recombinant human TSHR on their surface, and the other using soluble receptors extracted from these cells with detergent. In the intact cell TBI assay, monolayers expressing large numbers of TSHR were less effective than cells expressing few receptors. These findings are consistent with the very low concentration of TSHR autoantibodies in serum. Binding of[ 125I]human TSH was about 5-fold lower than that of[ 125I]bovine TSH to the intact cells. Nevertheless, TBI values with the two ligands were similar for most sera. However, a few sera produced greater inhibition of human than of bovine TSH binding. In the solubilized human TSHR TBI assay, in contrast to the intact cell TBI assay, cells expressing very large number of TSHR were an excellent source for detergent extraction of soluble human TSHR, but only if the cells were extracted while still on the dish and not after scraping. A 10-cm diameter dish of cells provided TSHR for 100–200 replicate determinations when substituted for solubilized porcine TSHR in a commercial TBI kit. TBI values in serum from 30 individuals with suspected Graves’ disease correlated closely when tested with solubilized human and porcine TSHR (r = 0.954; P < 0.001). However, 2 sera that were negative with the porcine TSHR were positive with the human TSHR. TBI and thyroid-stimulating activity in these sera correlated weakly regardless of whether the TBI used human or porcine TSHR. These findings open the way to a practical TBI assay using recombinant human TSHR.
Hemodynamic Effects of Parathyroid Hormone-Related Peptide-(1–34) in Humans1
Authors: Wolzt Michael , Schmetterer Leopold , Dorner Guido , Zelger Georg , Entlicher Jesusa , Kapiotis Stylianos , Eichler Hans-Georg
Published: January 2014

It has been suggested that PTH-related peptide-(1–34) (PTHrP) is a regulator or modulator of regional or systemic cardiovascular function with varying vasodilating actions in different species. We have studied the cardiovascular pharmacodynamic profile of PTHrP in healthy humans.

In a double blind, placebo-controlled, cross-over study design, eight healthy subjects were assigned to stepwise increased iv doses of PTHrP. In addition, a dose-response curve to PTHrP was constructed in a dorsal hand vein in eight subjects.

PTHrP dose-dependently increased pulse rate and renal plasma flow by more than 50% (P < 0.0001 for both parameters, by ANOVA), but only a small venodilating response was seen in hand vein experiments, and no effect was noted on mean arterial blood pressure or cardiac inotropic performance.

Although it is unlikely that PTHrP regulates systemic hemodynamics, its chronotropic effect and its potent action on renal plasma flow may represent the primary cardiovascular physiological targets of action.
Growth Hormone Response to the Hypothalamic Somatostatinergic Activity in Acromegalic Patients1
Authors: Yang I. , Park S. , Woo J. , Kim S. , Kim J. , Kim Y. , Choi Y.
Published: January 2014

Oral glucose administration suppresses the TRH-induced TSH response by enhancing the hypothalamic somatostatinergic activity (HSA). We assessed the HSA in 13 acromegalic patients by measuring glucose-induced suppression of TRH-stimulated TSH secretion. The HSA showed wide variation with up to 64% suppression. The mean HSA of the patients (25 ± 6%) did not differ from that in normal young men (19 ± 4%) in our previous study. Six patients had normal or low HSA, and the other 7 patients had high HSA. The mean TRH-stimulated TSH levels of the patients with normal or low HSA was significantly lower than that of the patients with high HSA (5.13 ± 0.10 vs. 11.30 ± 2.80 mU/L). The HSA did not relate to sex, age, tumor size, basal GH levels, the paradoxical responses to TRH and GnRH, octreotide response, or the gsp oncogene. In the combined glucose-TRH test, glucose pretreatment completely suppressed the paradoxical increase in GH level at 30 min in 4 patients. However, it could suppress the paradoxical GH response by only 6–51% in the other 5 patients who also showed the paradoxical response in TRH test. The tumor diameter of patients with good response to the HSA was significantly larger than that of the patients with poor response (31 ± 5 vs. 14 ± 2 mm) as was the tumor grade (3.3 ± 0.3 vs. 1.7 ± 0.2). This study supports the idea that a reduction of HSA is not a primary cause of acromegaly, and the HSA seems to increase to suppress the autonomous secretion of GH from the pituitary adenomas. HSA as well as the response of tumors to HSA do not determine tumor growth.