bluuebunny/crossref_metadata_2025 huggingface dataset:
Loss of the C Terminus of Melanocortin Receptor 2 (MC2R) Results in Impaired Cell Surface Expression and ACTH Insensitivity
Authors: Hirsch Andrea , Meimaridou Eirini , Fernandez-Cancio Monica , Pandey Amit V. , Clemente María , Audi Laura , Clark Adrian J. L. , Flück Christa E.
Published: January 2014

Objective: Mutations in melanocortin receptor 2 (MC2R) and its related melanocortin receptor accessory protein (MRAP) cause familial glucocorticoid deficiency. We identified a novel MC2R mutation, K289fs. This unique mutation in the C terminus of MC2R is located in the intracellular part of the protein for which the exact function is unknown.

Setting: A 6-wk-old boy presented with severe hypoglycemia, unmeasurable cortisol, and grossly elevated ACTH but normal electrolytes. Genetic analysis revealed homozygote K289fs mutation in MC2R. His parents and siblings were heterozygous but phenotypically normal.

Intervention and Results: The role of the C terminus of MC2R was studied in two cell systems. Because the K289fs mutant changes the last eight amino acids of the protein and leads to protein elongation, wild-type MC2R and C-terminally mutated constructs were tested for activity to respond to ACTH in an OS3 cell-based reporter assay. Wild-type and alanine-substituted constructs responded normally to ACTH. By contrast K289fs and M290X had a total loss of activity. Cell surface assays and confocal localization studies revealed that K289fs and M290X receptors were not found at the cell surface, indicating that their transport from the endoplasmic reticulum to the cell membrane is disrupted. Interestingly, coimmunoprecipitation experiments showed no alteration in the interaction of mutant MC2R with MRAP, suggesting that interaction between these two proteins does not guarantee normal localization.

Conclusions: Loss of the C terminus of MC2R impairs cell surface expression and ACTH sensitivity but does not disrupt interaction of MC2R with MRAP. These findings highlight the extreme sensitivity of MC2R to structural disruption.
Implication of Oxygen-Regulated Protein 150 (ORP150) in Apoptosis Induced by Proteasome Inhibitors in Human Thyroid Cancer Cells
Authors: Gao Yan-Yan , Liu Bao-Qin , Du Zhen-Xian , Zhang Hai-Yan , Niu Xiao-Fang , Wang Hua-Qin
Published: January 2014

This article appears in The Journal of Clinical Endocrinology & Metabolism. 10.1210/jc.2010-1043
Profiling of Endogenous Estrogens, Their Precursors, and Metabolites in Endometrial Cancer Patients: Association with Risk and Relationship to Clinical Characteristics
Authors: Audet-Walsh Étienne , Lépine Johanie , Grégoire Jean , Plante Marie , Caron Patrick , Têtu Bernard , Ayotte Pierre , Brisson Jacques , Villeneuve Lyne , Bélanger Alain , Guillemette Chantal
Published: January 2014

Background: Endometrial cancer (EC) predominantly occurs after menopause and is strongly related to steroid hormones, particularly estrogens. However, the relationship between these hormones and clinical characteristics remains unaddressed.

Experimental Design: We analyzed the circulating levels of 18 steroids including adrenal precursors, androgens, estrogens, and their glucuronide metabolites, using specific and validated methods based on tandem mass spectrometry. Our goals were to compare circulating levels in postmenopausal women with EC (n = 126) with those of healthy postmenopausal women (n = 110) and to investigate how these hormonal levels relate to clinical characteristics.

Results: After adjustment for potential confounders, most hormones were significantly elevated in EC patients compared with healthy controls. In women with type I cancer, estrogen levels were up to 3-fold those of healthy women (P < 0.05). These higher levels were associated with an increased risk of cancer, particularly estrogens and their direct precursors, testosterone and androstenedione (odds ratios ranging from 4.4 to 13.3; P ≤ 0.0003). Elevated circulating levels of estrogens and their metabolites were found in cancer cases with type I endometrioid cancer and low-grade and noninvasive tumor, suggesting an association between these hormones and the tumoral estrogenic activity. In addition, levels of estrone sulfate in EC patients with relapse were 2-fold over levels of EC patients without relapse (P < 0.05), and 4.5-fold over those of healthy women (P < 0.001).

Conclusions: Circulating levels of steroids were associated with increased risk of EC. Estrogens may represent novel biomarkers predictive of clinical characteristics, including evidence for an increased risk of relapse.
Sex Differences in Lipid and Lipoprotein Metabolism: It's Not Just about Sex Hormones
Authors: Wang Xuewen , Magkos Faidon , Mittendorfer Bettina
Published: January 2014

It is commonly thought that sex hormones are important regulators of plasma lipid kinetics and are responsible for sexual dimorphism in the plasma lipid profile. Here we discuss the findings from studies evaluating lipid and lipoprotein kinetics in men and women in the context of what we know about the effects of exogenous sex hormone administration, and we conclude that it is more complicated than that. It has become clear that normal physiological alterations in the hormonal milieu (i.e. due to menopause or throughout the menstrual cycle) do not significantly affect plasma lipid homeostasis. Furthermore, parenterally administered estrogens have either no effect or only very small beneficial effects, whereas orally administered estrogens raise plasma triglyceride concentrations—a phenomenon that is not consistent with the observed sex differences and likely results from the hepatic “first-pass effect.” The effects of progestogens and androgens mimic only in part the differences in plasma lipids between men and women. Thus, the underlying physiological modulators of plasma lipid metabolism responsible for the differences between men and women remain to be elucidated.
Prevalence of Goiter and Urinary Iodine Excretion Levels in Children Around Chernobyl*
Authors: Ashizawa Kiyoto , Shibata Yoshisada , Yamashita Shunichi , Namba Hiroyuki , Hoshi Masaharu , Yokoyama Naokata , Izumi Motomori , Nagataki Shigenobu
Published: January 2014

The prevalence of goiter among children living in areas affected by the Chernobyl accident was investigated by analysis of data on approximately 120,000 children examined at five medical diagnostic centers in Belarus, Russia, and the Ukraine. Examinations of thyroid gland were conducted with an arch-automatic ultrasonographic instrument at the five centers under the same protocol. The diagnosis of goiter was established when the thyroid volume exceeded a limit calculated from age, height, and body weight of a child. A considerable variation by region was noted in the prevalence of goiter. Highest in the Kiev region, the prevalence in the five regions was 54% in Kiev, 38% in the Zhitomir regions of the Ukraine, 18% in Gomel, 22% in the Mogilev regions of Belarus, and 41% in the Bryansk region of Russia. Urinary iodine content was measured in approximately 5700 children, and an endemic iodine deficient zone was confirmed in the Bryansk, Kiev, and Zhitomir regions. A significant negative correlation was observed between the prevalence of goiter and the median level of urinary iodine content (Spearman’s rank correlation coefficient was −0.35, P = 0.025).
Increase in Plasma Thyrotropin Levels in Hypothyroid Patients during Treatment due to a Defect in the Commercial Preparation
Authors: Peran S. , Garriga M. J. , Morreale de Escobar G. , Asunción M. , Peran M.
Published: January 2014

Around mid-1995, the Molecular Endocrinology Laboratory of the Regional Hospital (Malaga, Spain) began detecting an increase in TSH levels in the serum of patients under study to control the treatment of hypothyroidism with levothyroxine. Over a period of 5 months, of a total of 467 hypothyroid patients treated with Levothroid, 53% had TSH levels higher than 6 μU/mL. The reliability of the biochemical results was verified by duplicating 56 randomly chosen samples from all those with high TSH levels and by an external control performed in four different laboratories. The amount of levothyroxine in the tablets was analyzed by RIA, high performance liquid chromatography, and their iodine contents. The lowest levels of levothyroxine found in the 50-μg Levothroid tablets were those determined by RIA, with a mean value of 32.3 μg, resulting in a 35.3% loss of activity. The mean value of levothyroxine found in these same tablets by high performance liquid chromatography was 39.3 μg, amounting to a 21.3% loss in activity. The iodine showed no significant loss in these tablets, with a mean experimental value of 48 μg. The commercial laboratory withdrew lot J from the market, the one in which these deficiencies were found.
Keratinocyte Growth Factor Expression in the Mesenchymal Cells of Human Amnion*
Authors: Casey M. Linette , MacDonald Paul C.
Published: January 2014

Amnion epithelial and mesenchymal cells were separated by differential protease treatment, and the separated cells were maintained in monolayer culture. Keratinocyte growth factor (KGF) messenger RNA (mRNA) was readily detected by Northern analysis of amnion mesenchymal cell total RNA (10 μg) but not in amnion epithelial cells. Treatment of the amnion mesenchymal cells in serum-free medium with tetradecanoyl phorbol acetate (1 nm) caused an increase in the level of KGF mRNA. Forskolin treatment also caused an increase in KGF mRNA but not to the levels attained with tetradecanoyl phorbol acetate treatment. Dexamethasone (1 nm) treatment of these cells effected a reduction in the level of KGF mRNA. Prolonged maintenance of mesenchymal cells in serum-free medium also was associated with an increase in the level of KGF mRNA. Treatment with a variety of other agents, viz., interleukin (IL)-1, IL-6 plus or minus IL-6 soluble receptor, IL-11, oncostatin M , epidermal growth factor (EGF), and transforming growth factor-β did not modify the level of KGF mRNA. Treatment of amnion epithelial cells with KGF caused an increase in the rate of [3H]thymidine incorporation, but the rate of cell replication induced by KGF was less than that induced by treatment with EGF. Transforming growth factor-β treatment inhibited basal and EGF- and KGF-stimulated amnion epithelial cell replication. The findings of this study are indicative that KGF is expressed in human amnion mesenchymal cells, and that KGF may act on the epithelial cells of this tissue.
The Localization of Androgen Receptors in Human Bone
Authors: Abu E. O. , Horner A. , Kusec V. , Triffitt J. T. , Compston J. E.
Published: January 2014

Androgens have important effects on the human skeleton, and deficiency has been associated with bone loss in both males and females. The skeletal actions of androgens may be mediated directly via the androgen receptor (AR) or indirectly via the estrogen receptor after aromatization to estrogens. The presence of androgen receptors has been demonstrated in bone cells and chondrocytes in vitro, but their presence in human bone in situ has not been reported. In order to provide further evidence for a direct action of androgens on bone via androgen receptors, we have used specific monoclonal antibodies to investigate the expression of human AR in normal developing and osteophytic bone of both sexes.

In the growth plates from the developing bone, androgen receptors were predominantly expressed in hypertrophic chondrocytes and in osteoblasts at sites of bone formation. They were also observed in osteocytes in the bone, and in mononuclear cells and endothelial cells of blood vessels within the bone marrow. In the osteophytes, androgen receptors were widely distributed at sites of endochondral ossification in proliferating, mature, and hypertrophic chondrocytes and at sites of bone remodeling in osteoblasts. They were also expressed in osteocytes and mononuclear cells within the bone marrow. The pattern and number of cells expressing the receptor was similar in both sexes.

Our results show for the first time the presence and distribution of androgen receptors in normal developing human and osteophytic bone in situ and further provide evidence for a direct action of androgens on bone and cartilage cells.
Long-Term and Low-Dose Treatment with Cabergoline Induces Macroprolactinoma Shrinkage
Authors: Colao Annamaria , Di Sarno Antonella , Landi Maria Luisa , Cirillo Sossio , Sarnacchiaro Francesca , Facciolli Giuseppina , Pivonello Rosario , Cataldi Mauro , Merola Bartolomeo , Annunziato Lucio , Lombardi Gaetano
Published: January 2014

Cabergoline (CAB), a long-lasting dopamine-agonist, specific for the D2 receptor, is effective in normalizing serum PRL levels in most patients with microprolactinoma or idiopathic hyperprolactinemia. Because few data are presently available on the effects of CAB treatment in macroprolactinomas, the aim of this open-label study was to investigate whether this drug was effective in producing tumor shrinkage, as well as in normalizing PRL levels.

Twenty-three patients with macroprolactinoma entered this study: 15 patients had had no treatment, whereas the remaining 8 patients had been previously treated with bromocriptine, which was withdrawn because of intolerance. Three of 23 patients had undergone unsuccessful surgery. Pretreatment serum PRL levels ranged from 100-3860 μg/L.

CAB was administered at a dose of 0.5–3 mg once or twice a week for 12–24 months. Magnetic resonance imaging (MRI) scans were performed before and 3, 6, 12, and 24 months after the beginning of treatment, to evaluate tumor shrinkage, defined as a decrease of at least 80% of baseline tumor volume.

After 3–6 months of treatment with a low dose (0.5–1 mg/week), serum PRL levels normalized in 18 patients. In the remaining 5 patients, whose serum PRL levels were not normalized, the dose was increased to 2–3 mg/week. This schedule caused the normalization of PRL levels in 1 patient, whereas in the remaining 4 patients, PRL levels were reduced to 30–82 μg/L. A tumor volume reduction greater than 80% at MRI occurred in 14 of 23 patients (61%) after CAB treatment (from 2609.4 ± 534.7 to 530.1 ± 141.3 mm3 at the 12–24th month follow-up, P < 0.001). A volume reduction of 41.8 ± 3.4% was already evident after 3 months (1436 ± 285.9 mm3; P < 0.001). The complete disappearance of the tumor mass at MRI occurred after 6 months of treatment with CAB in 1 patient, and in 5 patients after 1 yr of treatment. An improvement of visual field defects was obtained in 9 of the 10 patients presenting visual impairment before CAB treatment. The drug was tolerated well by all patients. Only 1 patient experienced mild nausea, which disappeared spontaneously after the 2nd day of treatment.

Long-term, a low dose of the D2 receptor agonist CAB significantly reduced tumor volume and normalized serum PRL levels in a great majority of patients bearing macroprolactinoma. This treatment met with excellent patient compliance. This study suggests that CAB can be used as a first choice drug treatment in macroprolactinomas, as already shown for microprolactinomas and idiopathic hyperprolactinemia.
Racial Differences in Bone Density between Young Adult Black and White Subjects Persist after Adjustment for Anthropometric, Lifestyle, and Biochemical Differences*†
Authors: Ettinger Bruce , Sidney Stephen , Cummings Steven R. , Libanati Cesar , Bikle Daniel D. , Tekawa Irene S. , Tolan Kimberly , Steiger Peter
Published: January 2014

This study tested whether racial differences in bone density can be explained by differences in bone metabolism and lifestyle. A cohort of 402 black and white men and women, ages 25–36 yr, was studied at the Kaiser Permanente Medical Care Program in Northern California, a prepaid health plan. Body composition (fat, lean, and bone mineral density) was measured using a Hologic-2000 dual-energy x-ray densitometer. Muscle strength, blood and urine chemistry values related to calcium metabolism, bone turnover, growth factors, and level of sex and adrenal hormones were also measured. Medical history, physical activity, and lifestyle were assessed. Statistical analyses using t- and chi-square tests and multiple regression were done to determine whether racial difference in bone density remained after adjustment for covariates. Bone density at all skeletal sites was statistically significantly greater in black than in white subjects; on average, adjustment for covariates reduced the percentage density differences by 42% for men and 34% for women. Adjusted bone density at various skeletal sites was 4.5–16.1% higher for black than for white men and was 1.2–7.3% higher for black than for white women. We concluded that racial differences in bone mineral density are not accounted for by clinical or biochemical variables measured in early adulthood.
Angiotensin II Receptors in Cortical and Medullary Adrenal Tumors1
Authors: Opocher Giuseppe , Rocco Stefano , Cimolato Margherita , Vianello Barbara , Arnaldi Giorgio , Mantero Franco
Published: January 2014

Several pieces of evidences suggest that angiotensin II (Ang II) has mitogenic effects, and a link between Ang II receptors and adrenal tumors can be suggested. In various adrenal tumors, aldosterone-producing adenoma (APA), Cushing’s adrenal adenomas (Cush), pheochromocytomas (Pheo), and adrenal carcinomas, we studied the density, affinity, and subtype of Ang II receptors. Ang II binding was tested in cell membrane homogenates. [125I]Ang II was used as ligand, and Losartan and CGP 42112 were used as selective Ang II type 1 and type 2 antagonists, respectively. In APA, Ang II receptor density was 178.5 ± 82.7 fmol/mg: however, due to the high degree of variability, the receptor density was not significantly higher than that in nontumorous adrenal cortex (59.3 ± 8.4 fmol/mg). In Cush, the receptor density (27.6 ± 8.2 fmol/mg; P< 0.05) was significantly lower than that in controls, whereas in Pheo and cortical carcinoma, Ang II binding was very low and in several cases almost undetectable. There was no remarkable difference in the Ang II receptor affinity among all tissues tested. The ratio between type 1 and type 2 Ang II receptors showed a large prevalence of type 1 in controls, APA, and three cases of Cush; in two cases of Cush, this ratio was reversed.

In conclusion, our data indicate that Ang II receptors are normally expressed in APA and can also be detected in Cush, whereas they have a very low density in Pheo and adrenal carcinoma. Therefore, Ang II receptors are not involved in the lack of response to Ang II that is characteristic of APA; additionally, a reduction of Ang II receptors can be associated with dedifferentiation or malignancy of adrenal tumors. Further investigation of the expression and functional characterization of Ang II receptors is required to better clarify their possible role in adrenal tumorigenesis.
Independent Genetic Factors Determine the Amount and Distribution of Fat in Women after the Menopause1
Authors: Samaras K. , Spector T. D. , Nguyen T. V. , Baan K. , Campbell L. V. , Kelly P. J.
Published: January 2014

Central adiposity is a strong predictor of cardiovascular disease in women. We studied postmenopausal twins to explore the strength and the relationship between genetic influences on body fat and its distribution in a group where cardiovascular disease is the major cause of mortality. Healthy twin women were recruited from a national media campaign. One hundred nineteen monozygotic (MZ) and 97 dizygotic twin pairs were studied (mean ± se age 60 ± 0.3 yr, 10 ± 0.4 yr post menopausal). Total and central body fat were measured by dual-energy x-ray absorptiometry. Intrapair resemblance was significantly greater in MZ pairs for total fat (MZ vs. dizygotic, r = 0.70 ± 0.05 vs. r = 0.46 ± 0.08, P = 0.005) and central fat (r = 0.62 ± 0.06 vs. r = 0.35 ± 0.09, P = 0.005), suggesting a strong genetic influence on these traits. Model-fitting analysis indicated that genetic factors contribute up to 60% of total population variance in both total and central body fat. The heritability of central fat remained, after adjustment for the heritability of total fat, suggesting an independent genetic influence on fat distribution. These results were unchanged after adjusting for the effects of estrogen replacement and smoking.

In conclusion, total adiposity and central abdominal fat mass in normal postmenopausal women are under strong genetic influence. The data suggest that some of the genes responsible for central adiposity and its metabolic sequelae will be different from those responsible for total adiposity.
Fluoride at Mitogenic Doses Induces a Sustained Activation of p44mapk, but Not p42mapk, in Human TE85 Osteosarcoma Cells*
Authors: Wu Li-Wha , Yoon Hyun Koo , Baylink David J. , Graves Lee M. , Lau K.-H. William
Published: January 2014

Fluoride, at micromolar concentrations, stimulates bone cell proliferation in vitro. In this study, we sought to test whether fluoride at mitogenic doses increases the tyrosyl phosphorylation level and specific activity of a mitogen-activated protein kinase (MAPK) in human TE85 osteosarcoma cells. Analysis by immunoprecipitation with antiphosphotyrosine antibody followed by Western analysis using an anti-pan extracellular signal-regulated kinase antibody revealed that fluoride at the optimal mitogenic dose (i.e. 100 μmol/L) induced a time-dependent increase in the steady state tyrosyl phosphorylation level of p44mapk, but not p42mapk, with the maximal increase (4- to 13-fold) after 1–3 h fluoride treatment. The effect was sustained in that a 9-fold increase was seen after 12 h of the fluoride treatment. The sustained nature of the effect is consistent with an inhibition of dephosphorylation rather than a direct stimulation of phosphorylation. The fluoride effect on the tyrosyl phosphorylation level of p44mapk was dose dependent, with the optimal dose being 100μ mol/L fluoride. The mitogenic dose of fluoride also increased the specific activity and the in-gel kinase activity of p44mapk, but not that of p42mapk, in a time-dependent manner similar to the effect on the p44mapk tyrosyl phosphorylation level. Fluoride at the same micromolar doses did not increase cell proliferation, tyrosyl phosphorylation, or specific activity of any MAPK in human skin foreskin fibroblasts, which are fluoride-nonresponsive cells. Consistent with the interpretation that the effect of fluoride on the steady state tyrosyl phosphorylation level of p44mapk is a consequence of an inhibition of a phosphotyrosyl phosphatase (PTP), mitogenic doses of orthovanadate, a bone cell mitogen and a PTP inhibitor, also increased the steady state tyrosyl phosphorylation level of p44mapk, but not p42mapk, in a time-dependent sustained manner similar to that observed with fluoride. Together, these findings support the concept that inhibition of a PTP activity in bone cells could lead to an activation of MAPK activity.
Spontaneous Feminization in a 46,XX Female Patient with Congenital Lipoid Adrenal Hyperplasia Due to a Homozygous Frameshift Mutation in the Steroidogenic Acute Regulatory Protein*
Authors: Bose Himangshu S. , Pescovitz Ora Hirsch , Miller Walter L.
Published: January 2014

The most severe form of congenital adrenal hyperplasia (CAH) is lipoid CAH. It was once thought that this disease was due to mutations in the cholesterol side-chain cleavage enzyme system, thus eliminating the ability to convert cholesterol to pregnenolone, causing a complete absence of steroid hormone production. We recently showed that lipoid CAH is due to mutations in the steroidogenic acute regulatory (StAR) protein, thus preventing acutely stimulated adrenal and gonadal responses to tropic stimulation. However, this lesion may permit low levels of StAR-independent steroidogenesis to persist until the accumulation of intracellular lipid deposits destroys steroidogenic capacity. This model would predict that the steroidogenic cells of the ovaries of affected 46,XX females should remain undamaged until puberty, at which time low levels of StAR-independent estrogen biosynthesis should be detectable. We describe a 15.5-yr-old 46,XX female with a classic history of lipoid CAH who underwent spontaneous feminization and cyclical vaginal bleeding beginning at age 13. Genetic analysis of the patient and her parents showed that she was homozygous for the novel StAR frameshift mutation 261delT. This is the first adolescent female with lipoid CAH who has undergone spontaneous feminization and who has been analyzed genetically. Finding an inactive StAR gene in this patient confirms our two-hit model of the pathogenesis of lipoid CAH, in which loss of StAR activity initially preserves StAR-independent steroidogenesis, which is lost only after cells undergo chronic tropic stimulation and subsequent damage from accumulation of cholesterol esters.
Elevated Serum Insulin-Like Growth Factor-Binding Protein 2 (IGFBP-2) and Decreased IGFBP-3 in Epithelial Ovarian Cancer: Correlation with Cancer Antigen 125 and Tumor-Associated Trypsin Inhibitor1
Authors: Flyvbjerg Allan , Mogensen Ole , Mogensen Bent , Nielsen Ole Steen
Published: January 2014

Insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs) recently have been shown to play a physiological role in the female genital system, including the ovarian follicular system. However, little is known about the role of the IGF system in malignant ovarian disease. To assess possible mutual correlations between alterations in circulating IGFBP profiles and tumuor markers in patients with epithelial ovarian cancer, we performed an RIA for IGFBP-2 and IGFBP-3 and a Western ligand blotting (WLB) in serum samples from 20 patients with epithelial ovarian cancer, 10 patients with benign ovarian tumors, and 8 healthy age-matched controls. The epithelial ovarian cancer group had a mean IGFBP-2 level that was 253% (RIA) and 105% (WLB) above that of controls. IGFBP-2 even correlated positively with the highly sensitive serum tumor marker, cancer antigen 125 (CA 125) (r = 0.71, P < 0.001) but not with the less sensitive tumor-associated trypsin inhibitor. In contrast, serum IGFBP-3 (by RIA and WLB) was decreased in patients with ovarian cancer, and IGFBP-3 proteolytic activity was detectable in some of the patients. Neither IGFBP-3 nor IGFBP-3 proteolytic activity correlated with CA 125; but the former correlated inversely, and the latter positively, with tumor-associated trypsin inhibitor.

In conclusion, IGFBP-2 levels are high in serum of epithelial ovarian cancer patients, and the increment in serum IGFBP-2 correlates positively with CA 125. Alterations in serum IGFBP-2 levels may, therefore, serve as a potential additional marker for ovarian cancer.
Metabolism of Oral Glucose in Pancreas Transplant Recipients with Normal and Impaired Glucose Tolerance1
Authors: Christiansen E. , Tibell A. , Vølund Aa. , Holst J. J. , Rasmussen K. , Schäffer L. , Madsbad S.
Published: January 2014

To gain insight into the pathophysiology of impaired glucose tolerance in pancreas transplantation, glucose kinetics and insulin secretion were assessed after an oral glucose load in four combined pancreas-kidney recipients with impaired glucose tolerance (IPx), in five combined pancreas-kidney recipients with normal glucose tolerance, in six nondiabetic kidney transplant recipients, and in eight normal subjects employing a dual isotope technique. β-Cell function was evaluated by calculating prehepatic insulin secretion rates, which subsequently were correlated to the ambient glucose concentrations to obtain an index of β-cell responsiveness. Oxidative and nonoxidative glucose metabolism were assessed by indirect calorimetry. Basal insulin secretion rates, the glucose-stimulated early insulin secretion rates, as well as β-cell responsiveness were markedly reduced in IPx than in the glucose-tolerant transplant subjects. Total systemic glucose appearance was similar in the groups with apparently comparable inhibition of systemic glucose release and increase in exogenous glucose appearance. The hyperglycemic response in IPx was due to a significant reduction in the glucose disappearance rates during the first 2 h after glucose ingestion. Nonoxidative glucose metabolism increased significantly less in IPx than in glucose-tolerant groups. Glucagon secretion was less suppressed in the early part of the study in IPx, which may have contributed to the excessive hyperglycemia.

In conclusion, IPx after pancreas transplantation was characterized by 1) impaired early insulin secretion, 2) reduced β-cell responsiveness, 3) reduced glucose uptake, 4) impaired nonoxidative glucose metabolism, and 5) impaired early inhibition of glucagon secretion.
Free Insulin-Like Growth Factor I Serum Levels in 1430 Healthy Children and Adults, and Its Diagnostic Value in Patients Suspected of Growth Hormone Deficiency1
Authors: Juul Anders , Holm Kirsten , Kastrup Knud W. , Pedersen Søren A. , Michaelsen Kim Fleischer , Scheike Thomas , Rasmussen Susanne , Müller Jørn , Skakkebæk Niels E.
Published: January 2014

Serum levels of total insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) reflect endogenous GH secretion in healthy children, which makes them good diagnostic markers for screening of GH deficiency (GHD) in short children, although some controversy still exists. Only a minor fraction of the total IGF-I circulates in its free form, which is believed to be the biologically active form. However, our knowledge of the clinical or physiological value of determination of free IGF-I in serum is limited at present. In adults, the diagnostic value of total IGF-I and IGFBP-3 determinations in patients suspected of GHD has only been reported in a few studies, whereas no previous reports on the diagnostic value of free IGF-I levels in adults suspected of GHD exist.

Serum levels of free IGF-I were determined in 1430 healthy children, adolescents, and adults by a newly developed, commercially available immunoradiometric assay (Diagnostic Systems Laboratories) to establish valid normative data for this analysis. We studied the diagnostic value of free IGF-I in relation to total IGF-I and IGFBP-3 determinations in adults who were suspected of GHD. A GH provocative test, using oral clonidine, was performed in 108 adult patients who had previously been treated with GH in childhood.

In healthy subjects, free IGF-I levels increased during childhood, with the highest mean values during puberty. After puberty, a subsequent decline in serum levels of free IGF-I was apparent. We found unmeasurable free IGF-I values in 34 of the prepubertal children (3.3%). All individuals over 8 yr of age had measurable free IGF-I levels that amounted to approximately 1% of the total IGF-I concentrations. Free IGF-I levels were below −2 sd in 56 of 79 GHD patients (sensitivity, 71%) and above −2 sd in 24 of 29 patients with a normal GH response (specificity, 83%). Multiple linear regression analysis demonstrated that free IGF-I was significantly dependent on peak GH levels, duration of the disease, and number of other pituitary axes affected.

We conclude that free IGF-I serum levels increase during childhood with a peak in puberty, whereafter free IGF-I levels return to prepubertal levels. Three percent of healthy prepubertal children had unmeasurable free IGF-I levels using this assay. We found that determination of the free IGF-I serum concentration may predict the outcome of a GH provocative test in adults suspected of GHD, but that a single determination of free IGF-I offered no significant advantage compared to determination of total IGF-I or IGFBP-3 serum levels.
Short-Term Variations in Bone Remodeling Biochemical Markers: Cyclical Etidronate and Alendronate Effects Compared
Authors: Bettica P. , Bevilacqua M. , Vago T. , Masino M. , Cucinotta E. , Norbiato G.
Published: January 2014

Bone-remodeling markers have been proposed to monitor antiosteoporotic therapy, as substantial changes in these markers usually occur in a relatively short time interval. In this study we have evaluated the short term effects of two bisphosphonates on bone-remodeling markers with the aim of 1) defining the shortest reliable time interval after which markers should be measured, and 2) comparing the effects of different bisphophonates. To do so, 74 postmenopausal women with a lumbar spine t score of at least −1 were randomly allocated to 4 different treatments: calcium carbonate (500 mg/day; n = 18), 5 mg/day alendronate (A5; n = 18), 10 mg/day alendronate (A10; n = 20), and cyclical etidronate (CE; n = 18). Serum and 24-h urine samples were collected at baseline and 14, 28, 56, and 84 days after the beginning of therapy. Type I collagen N-terminal (NTx) and C-terminal (CTx) telopeptides and total deoxypyridinoline (tDPD) were measured in urine and normalized for urinary creatinine excretion. Osteocalcin and bone alkaline phosphatase in serum were measured. Alendronate (at both doses) and CE significantly decreased bone-remodeling markers, whereas calcium carbonate did not. Bone resorption markers reduction reached a plateau 14 (A10) or 28 (A5 and CE) days after the beginning of treatment, whereas osteocalcin and bone alkaline phosphatase were significantly reduced at 56 (A10) and 84 (CE) days. The global effects of alendronate and CE on NTx and CTx (calculated as the area under the curve) were significantly different from those of calcium (P < 0.05), but were not significantly different from each other. The percent change from baseline obtained with tDPD, NTx, or CTx during bisphosphonate treatment were significantly different (P < 0.05), but this difference disappeared when the variability in the calcium carbonate group was taken into account. In conclusion, this study shows that 1) etidronate and alendronate induce a significant and rapid reduction in bone-remodeling markers; 2) the changes in NTx, CTx, and tDPD urinary excretions reach a plateau after 2–4 wk of treatment; and 3) short term treatments with CE or alendronate induce similar changes in the urinary excretion of NTx and CTx.
Transsphenoidal Microsurgery for Growth Hormone-Secreting Pituitary Adenomas: Initial Outcome and Long-Term Results
Authors: Abosch Aviva , Tyrrell J. Blake , Lamborn Kathleen R. , Hannegan Lisa T. , Applebury Carol B. , Wilson Charles B.
Published: January 2014

Treatment of acromegaly has long been recognized as necessary to relieve symptoms, halt progression of deformities, and decompress the sella turcica. More recently, treatment strategies have focused on decreasing GH levels to a point at which mortality rates normalize, thereby redefining previous concepts of a cure. No surgical series to date has investigated the long-term effect of treatment on mortality rates. We retrospectively reviewed 254 consecutive patients with acromegaly who underwent transsphenoidal microsurgery of GH-secreting adenomas between 1974–1992. Seventy-six percent of these patients had basal GH levels <5 ng/mL within 30 days of surgery, and 24% had persistent disease. Multivariate analysis revealed that higher stage, grade, and preoperative GH levels were all predictive of persistence (P < 0.01). Long-term follow-up was obtained on 129 of the patients in initial remission. Of these, 9 (7%) had disease recurrence and 120 remained in remission. The incidence of major postoperative complications was 8% (2% permanent diabetes insipidus, 2% cerebrospinal fluid leaks requiring surgery, 2% meningitis, and 2% hypopituitarism), with no mortality. In contrast to the 2.4- to 4.8-fold increased mortality among untreated acromegalics, the mortality rate among patients with posttherapy GH levels <5 ng/mL was equivalent to that of age- and sex-matched controls. Aggressive therapy to normalize GH levels should therefore be instituted at diagnosis.
Chronic Antagonism of Nuclear Factor-κB Activity in Cytotrophoblasts by Dexamethasone: A Potential Mechanism for Antiinflammatory Action of Glucocorticoids in Human Placenta1
Authors: Rosen Todd , Krikun Graciela , Ma Yuehong , Wang En-Yu , Lockwood Charles J. , Guller Seth
Published: January 2014

Circulating glucocorticoids are present in increasing quantities as human gestation progresses, peaking during labor whether it occurs before or at term. Although the precise role of glucocorticoids in pregnancy is not well defined, it is clear that glucocorticoids suppress inflammation in many cell types by antagonizing the acute stimulatory actions of members of the Rel/nuclear factor-κB (NF-κB) family on cytokine gene expression. In the present study we tested the hypothesis that during pregnancy, glucocorticoids chronically suppress inflammation in the human placenta. Cytotrophoblasts obtained from human term placentas were maintained for 48 h in culture medium supplemented with 10% charcoal-stripped calf serum with and without 100 nmol/L dexamethasone (DEX). Enzyme-linked immunosorbent assay studies revealed that cytotrophoblasts constitutively express interleukin-8 (IL-8), a known mediator of placental inflammation, between 24–96 h of culture. A 48-h treatment of cytotrophoblasts with 100 nmol/L DEX significantly reduced the production of IL-8 to 24± 1% of control levels (P < 0.01). DEX and cortisol mediated a dose-dependent inhibition of IL-8 expression, with ED50 values of 5 and 50 nmol/L, respectively. DEX treatment also significantly reduced levels of IL-6 and tumor necrosis factor-α in culture medium, suggesting that glucocorticoids coordinately reduce cytokine levels in cytotrophoblasts. As cytokine expression is regulated by NF-κB and activator protein-1 (AP-1) transcription factors, electrophoretic mobility shift assays (n = 4) were used to determine whether DEX treatment altered the binding of nuclear proteins from cytotrophoblasts to labeled oligonucleotides corresponding to the κB and AP-1 response elements. We observed that a 48-h treatment of cytotrophoblasts with 100 nmol/L DEX markedly reduced binding of nuclear extracts from cytotrophoblasts to the κB response element. DEX treatment promoted a relatively smaller reduction of binding to the AP-1 response element. Northern blotting experiments revealed that DEX treatment did not alter the level of IκB, p50, or p65 messenger ribonucleic acid, suggesting that the antiinflammatory action of glucocorticoid in cytotrophoblasts did not directly involve alterations in the level of NF-κB proteins. Our results demonstrate a novel chronic suppressive action of glucocorticoid on cytokine production and nuclear binding of NF-κB and AP-1 proteins in cytotrophoblasts, providing a potential mechanism through which glucocorticoids may suppress inflammation at maternal-fetal interfaces across gestation.
Decrease of Telomere Length in Thyroid Adenomas without Telomerase Activity
Authors: De Deken X. , Vilain C. , Van Sande J. , Dumont J. E. , Miot F.
Published: January 2014

In somatic cells, telomeres shorten with population doubling, thus limiting their capacity to divide. Telomerase, which synthesizes telomeric repeats, can compensate for such shortening. Telomerase activity is known to be absent from most somatic differentiated cells but is present in germline cells, immortal cell lines, or a large majority of malignant tumors. Autonomous thyroid adenomas are benign tumors composed of highly differentiated cells characterized by TSH-independent function and growth. Telomere length and telomerase activity were measured in autonomous and hypofunctioning adenomas and their surrounding tissues. A significant decrease of 3.8 ± 1.0 kilobases (kb) was observed in the length of the terminal restriction fragments (TRF) in 12 autonomous adenomas (8.6 ± 1.1 kb), compared with the TRF length of their surrounding tissues (12.4 ± 1.6 kb). The same kind of decrease, 3.5 ± 1.2 kb, was also observed in 16 hypofunctioning adenomas (12.3 ± 1.7 kb in surrounding tissue and 8.8 ± 1.6 kb in the adenomas). No telomerase activity was detected either in the 12 autonomous adenomas studied or in most of the quiescent tissues (10 of 12). Most of the hypofunctioning adenomas tested (15 of 16) did not display telomerase activity. These results suggest that the cells have undergone a higher number of cell divisions in the adenomas than in the surrounding tissue. Moreover, there is a larger spread of the TRF length distribution in autonomous adenomas than in the collateral tissue. This could reflect the heterogeneity in proliferation status of the cells in the nodule, some of which have reached the end of their life span, whereas others are still proliferating (but with no malignant potential for the autonomous adenomas). In conclusion, benign adenomas exhibit a shorter and more variable telomere length than the normal collateral quiescent tissue, with no telomerase activity to compensate this loss in telomere length.
A Change from Stimulatory to Blocking Antibody Activity in Graves’ Disease during Pregnancy1
Authors: Kung A. W. C. , Jones B. M.
Published: January 2014

Remission of Graves’ disease (GD) during pregnancy with recrudescence after delivery is commonly observed. However, as pregnancy is associated with type 2 rather than type 1 cytokine production, a decrease in thyroid-stimulating antibody (TSAb) activity alone is unlikely to account for the remission during pregnancy. We hypothesized that a change in the antibody characteristics may occur as pregnancy advances. Fifteen women were studied in the first, second, and third trimesters of pregnancy and 4 months postpartum. TSH receptor antibodies were determined using human thyroid cell cultures, and lymphocyte subsets were measured by flow cytometry.

Median TSAb (determined by cAMP release) decreased from 280% (96–3200) to 130% (range, 35–350; P < 0.05) during pregnancy, but no significant change was noted with the TSH binding inhibitory antibody (TBII; determined by RRA). Thyroid stimulation-blocking antibody (TSBAb; inhibition of TSH-stimulated cAMP release) increased from 16 ± 9% to 43 ± 16% (mean ± sd; P < 0.005). The increase in TSBAb was observed even among those patients who were in clinical remission before pregnancy. Overall, a negative correlation was observed between TSBAb activities and free T4 levels during pregnancy (r = −0.279; P < 0.05). Reciprocal changes in TSAb, TBII, and TSBAb levels were observed in the seven patients who relapsed during the postpartum period. In comparison, the healthy pregnant women (n = 14) were all negative for TSAb, TBII, and TSBAb throughout pregnancy.

The absolute number of T lymphocytes, T helper cells, and natural killer cells, but not B cells, decreased significantly during pregnancy in both healthy women and GD patients. GD patients had significantly more CD5+ B cells at all stages of pregnancy compared to controls. In conclusion, a change in specificity from stimulatory to blocking antibodies was observed in GD patients during pregnancy and may contribute to the remission of GD during pregnancy.
Testolactone-Associated High Androgen Levels, a Pharmacologic Effect or a Laboratory Artifact?1
Authors: Cummings Elizabeth A. , Salisbury Sonia R. , Givner Morris L. , Rittmaster Roger S.
Published: January 2014

Testolactone, an aromatase inhibitor, blocks conversion of androgens to estrogens. In familial male precocious puberty, slowing of pubertal progression and growth velocity occurs with testolactone and spironolactone. Girls with McCune-Albright syndrome, given testolactone, respond similarly. A 2-yr-old female (case 1) on testolactone for non-McCune-Albright gonadotropin independent precocious puberty had marked elevations of androstenedione (18 ng/mL, normal: 0.2–3.1) and testosterone (3.6 ng/mL, normal < 0.2) but no virilization. Investigations were undertaken to determine whether elevations in testosterone and androstenedione were caused by interference in these RIAs. After a single oral dose of testolactone (5 mg/kg in case 1; 4 mg/kg in case 2, a 3-yr-old boy with familial male precocious puberty; 10 mg/kg in a healthy postmenopausal control), serum testosterone and androstenedione were measured serially by RIA for 24 h. Androstenedione went from normal to a mean peak of 45.4 ng/mL at 1–2 h and returned to baseline by 24 h. Testosterone, undetectable at baseline (case 1 and control) or 1.8 ng/mL (case 2) rose to a mean peak of 6.9 ng/mL and returned to baseline by 24 h. Testolactone, in serial dilutions, cross-reacted in the testosterone assay. Testolactone significantly interferes in these serum RIAs, making their use unreliable in follow-up of patients treated with testolactone.
Luteinizing Hormone and Human Chorionic Gonadotropin Decrease Type 2 5α-Reductase and Androgen Receptor Protein Levels in Women’s Skin
Authors: Bird J. , Li X. , Lei Z. M. , Sanfilippo J. , Yussman M. A. , Rao Ch. V.
Published: January 2014

The present study tested the hypothesis that LH/hCG may regulate the type 2 5α-reductase and androgen receptor protein levels in skin. The skin samples obtained from women undergoing abdominal laparotomy or abdominoplasty were incubated in the presence or absence of hCG. Western blotting was then performed to determine the response of type 2 5α-reductase and androgen receptors. The results demonstrated that treatment with hCG resulted in a significant time- and dose-dependent, although modest, decrease in 5α-reductase and androgen receptor levels compared to the controls. These effects were mimicked by LH, but not by other hormones in the glycoprotein hormone family, includingα - and β-subunits of hCG. Although the biological and clinical importance of this regulation remains to be determined, these findings reaffirm that human skin is among the nongonadal tissues that respond to LH and hCG treatment.
Apparent Congenital Athyreosis Contrasting with Normal Plasma Thyroglobulin Levels and Associated with Inactivating Mutations in the Thyrotropin Receptor Gene: Are Athyreosis and Ectopic Thyroid Distinct Entities?1
Authors: Gagné N. , Parma J. , Deal C. , Vassart G. , Van Vliet G.
Published: January 2014

Loss-of-function mutations in the TSH receptor gene (TSH-R), usually leading to asymptomatic hyperthyrotropinemia, have been reported since 1995 in a total of eight pedigrees, with a pattern of transmission suggesting autosomal recessive inheritance. Although normal TSH secretion and action are not necessary for normal migration of the thyroid anlage, they are essential for normal thyroid growth and function. In keeping with this concept, we report a severely hypothyroid boy with a normally located but very hypoplastic and hypofunctional thyroid caused by TSH-R loss-of-function mutations. The propositus’ maternal great aunt also had apparent athyreosis. The propositus had undetectable uptake on 99mpertechnetate scintigraphy but normal plasma thyroglobulin at 15 days of age. He was found to be a compound heterozygote for TSH-R mutations, with the maternal allele carrying a splicing mutation (G to C transversion at position +3 of the donor site of intron 6) and the other allele a deletion of two nucleotides (2 bases of codon 655 in exon 10). The great aunt’s TSH-R was normal. We also report the sex ratio of hypothyroid newborns referred to our center since 1989 with apparent athyreosis (5 girls, 7 boys) and with ectopic thyroid tissue (41 girls, 15 boys). We conclude that different genetic and nongenetic mechanisms for athyreosis and ectopic thyroid are likely, and that these two distinct entities are themselves heterogeneous. Our results further show that inactivating mutations in TSH-R may account for some cases of apparent congenital athyreosis and should be suspected, especially if plasma thyroglobulin levels are normal.