bluuebunny/crossref_metadata_2025 huggingface dataset:
Adrenarche Results from Development of a 3β-Hydroxysteroid Dehydrogenase-Deficient Adrenal Reticularis1
Authors: Gell Jennifer S. , Carr Bruce R. , Sasano Hironobu , Atkins Baron , Margraf Linda , Mason J. Ian , Rainey William E.
Published: January 2014

Adrenarche is the increased adrenal production of dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) that occurs during the prepubertal period. To date, the exact mechanism initiating adrenarche is unknown, although many factors have been postulated. In the present study, we examined the hypothesis that alterations in intra-adrenal expression of 3β-hydroxysteroid dehydrogenase (3βHSD) or 21-hydroxylase (CYP21) within the inner reticularis zone leads to the increased production of 19-carbon (C19) steroids. After conversion of cholesterol to pregnenolone, 17α-hydroxylase/17,20-lyase (CYP17) can metabolize pregnenolone through to DHEA. The enzyme 3βHSD competes for substrate with CYP17 and effectively removes steroid precursor from the pathway leading to DHEA. On the other hand, deficiency in CYP21 expression is known to cause excessive production of adrenal C19 steroids, suggesting that CYP21 could play a role in adrenarche. Thus, a decrease in 3βHSD or CYP21 expression would allow substrate to flow toward the synthesis of DHEA. To determine whether adrenarche results from a decreased expression of 3βHSD or CYP21 in the reticularis, immunohistochemical localization of 3βHSD and CYP21 was performed, and staining intensities compared using adrenal glands from children ages 4 months to 4 yr (n = 12), ages 5–7 yr (n = 9), ages 8–13 yr (n = 9), and adults ages 25–56 yr (n = 8). There were no differences in the zonal expression of CYP21. No difference in 3βHSD staining was observed between the glomerulosa and fasciculata from any age group. However, children age 8 yr and older show a significant decrease in 3βHSD expression in reticularis as compared with the fasciculata. No significant difference was noted for 3βHSD levels between the fasciculata and reticularis for children age 7 yr or younger. The level of 3βHSD expression in the reticularis continued to decrease in the adult adrenals examined. These findings suggest that as children mature there is a decreased level of 3βHSD in the adrenal reticularis that may contribute to the increased production of DHEA and DHEAS seen during adrenarche.
Collagen Cross-Link Excretion during Space Flight and Bed Rest1
Authors: Smith Scott M. , Nillen Jeannie L. , LeBlanc Adrian , Lipton Allan , Demers Laurence M. , Lane Helen W. , Leach Carolyn S.
Published: January 2014

Extended exposure to weightlessness results in bone loss. However, little information exists as to the precise nature or time course of this bone loss. Bone resorption results in the release of collagen breakdown products, including N-telopeptide and the pyridinium (PYD) cross-links, pyridinoline and deoxypyridinoline. Urinary pyridinoline and deoxypyridinoline are known to increase during bed rest. We assessed excretion of PYD cross-links and N-telopeptide before, during, and after long (28-day, 59-day, and 84-day) Skylab missions, as well as during short (14-day) and long (119-day) bed-rest studies. During space flight, the urinary cross-link excretion level was twice those observed before flight. Urinary excretion levels of the collagen breakdown products were also 40–50% higher, during short and long bed rest, than before. These results clearly show that the changes in bone metabolism associated with space flight involve increased resorption. The rate of response (i.e. within days to weeks) suggests that alterations in bone metabolism are an early effect of weightlessness. These studies are important for a better understanding of bone metabolism in space crews and in those who are bedridden.
Bone Mass in Prepubertal Children: Gender Differences and the Role of Physical Activity and Sunlight Exposure1
Authors: Jones G. , Dwyer T.
Published: January 2014

Retrospective studies have suggested that the prepubertal years may be an important window of opportunity to increase bone mass, but there have been few direct studies and little exploration of gender differences in this age group. In this study, we report the associations among physical activity measures, sunlight exposure, body composition, and bone mass in 8-yr-old children. We studied 330 children in 1996 (115 girls and 215 boys; response rate, 60%) who had previously taken part in a cohort study of cot death in 1988. They had measurement of anthropometrics (height, weight, and body composition), sunlight exposure (by questionnaire), and physical activity[ questionnaire, muscle strength by dynamometry, and bicycle ergometric physical work capacity at a pulse of 170 beats/min (PWC170)]. Bone mineral density (BMD) was assessed at the spine, femoral neck, and total body by a Hologic QDR2000 densitometer. In females only, PWC170[ hip, 2.4%/quartile (95% confidence interval (CI), 0.3–4.5); spine, 1.7%/quartile (95% CI, 0.0–3.4); size adjusted] was associated with BMD, whereas in males only, BMD was associated with both sports participation (hip, 4.2% (95% CI, 1.1–7.3); spine, 4.3% (95% CI, 0.9–7.7)] and muscle strength [hip, 1.7%/quartile (95% CI, 0.0–3.4); but not spine; size adjusted]. Winter sunlight exposure was associated with BMD in girls [hip, 2.9%/category (95% CI, 0.7–5.0); spine, 3.6%/category (95% CI, 1.4–5.8)], but not in boys [hip, 0.3%/category (95% CI, −1.4 to +2.0); spine, 1.4%/category (95% CI, −0.7 to +3.5)]. Males and females were very similar in body size. However, males had higher size-adjusted BMD at the hip (9.6%; 95% CI, 6.9–14), whereas females had higher size-adjusted BMD at the spine (3.2%; 95% CI, 0.8–5.6%). In conclusion, this study has suggested that physical activity and exposure to sunlight are important in the bone mineralization of prepubertal male and female children. The magnitude of both gender and environmental differences in bone mass in this age group is substantial, suggesting that modification at this stage of life may influence peak bone mass and possibly fracture risk in later life.
Familial Resemblance for Bone Mineral Mass Is Expressed before Puberty1
Authors: Ferrari S. , Rizzoli R. , Slosman D. , Bonjour J.-P.
Published: January 2014

Genetic factors are known to explain a major proportion of peak bone mineral mass variance. Whether the influence of these genetic factors is expressed before the pubertal bone mineral mass accrual and whether there is tracking of bone mineral mass during pubertal growth, however, are not clearly established. We prospectively investigated correlations for bone mineral content (BMC), density, and bone size between prepubertal daughters and their premenopausal mothers.

Height, weight, lumbar spine (LS), femoral neck (FN) and midfemoral diaphysis BMC, bone area (BA), areal bone mineral density (aBMD), and volumetric bone mineral apparent density (BMAD) were evaluated in 138 mothers (mean age ± sd, 40.0 ± 4.0 yr) and their daughters (8.1 ± 0.7 yr), who were then remeasured at yearly intervals for 2 yr.

Eight-year-old prepubertal daughters had reached 78% and 44% of their mothers’ height and weight, respectively. At the various skeletal sites, they had reached 33–43% of their mothers’ BMC, 47–69% of their BA, 59–78% of their aBMD, and 75–105% of their BMAD. All body size and bone traits (age-adjusted Z-scores) were significantly correlated between prepubertal daughters and their mothers (r: 0.22–0.36, P < 0.01), except midfemoral diaphysis BMAD. Heritability estimates (1/2 h2), after adjustment for body size and dietary calcium intake, showed that 18–37% of bone traits were directly determined by maternal descent. During the next 2 yr, growth was accompanied by a marked increase of BMC, aBMD, and BA, whereas BMAD changed very little. In contrast, during this period, there were only minor changes in body size or bone trait Z-scores (i.e. <0.5 Z-scores), which were thus highly correlated between consecutive measurements (r: 0.75–0.92, P < 0.0001). Accordingly, mother-daughter correlations remained unchanged over that period.

Although more than 60% of peak bone mineral mass is gained during puberty (mostly at the expense of an increase in bone size while volumetric bone density slightly changes), familial resemblance for most bone traits is already present between daughters and their mothers before puberty. In the girls, moreover, yearly measurements were highly correlated, suggesting tracking of bone traits during pubertal growth. These results indicate that genetic susceptibility to osteoporosis may already be detectable in early childhood.
The Aromatase Excess Syndrome Is Associated with Feminization of Both Sexes and Autosomal Dominant Transmission of Aberrant P450 Aromatase Gene Transcription1
Authors: Stratakis Constantine A. , Vottero Alessandra , Brodie Angela , Kirschner Lawrence S. , DeAtkine David , Lu Qing , Yue Wei , Mitsiades Constantine S. , Flor Armando W. , Chrousos George P.
Published: January 2014

Increased extraglandular aromatization has been reported as the cause of familial gynecomastia. We studied a kindred with aromatase excess inherited in an autosomal dominant manner, in which affected males had heterosexual precocity and/or gynecomastia, and affected females had isosexual precocity and/or macromastia.

The propositus was a 9-yr-old boy with gynecomastia. His 7.5-yr-old sister had precocious puberty, and their father and paternal grandmother had peripubertal gynecomastia and macromastia, respectively. Serum concentrations of gonadal and adrenal steroid hormones were determined before and after the administration of corticotropin and/or hCG. Aromatase activity was determined by[ 3H]Δ4-androstenedione to[ 3H]estrone conversion by cultured skin fibroblasts and/or Epstein-Barr virus-transformed lymphocytes and was detected by immunohistochemistry and/or Western analysis. Linkage was examined with a polymorphism of the aromatase (P450arom) gene. The P450arom messenger ribonucleic acid was analyzed by rapid amplification of complementary DNA (cDNA) ends, ribonuclease protection assay, and RT-PCR.

hCG testing demonstrated a high rate of conversion ofΔ 4-androstenedione to estrone and of testosterone to estradiol in the propositus and his father. Treatment of the propositus and his sister was initiated with an aromatase inhibitor (testolactone) and a GnRH analog, which successfully delayed skeletal and pubertal development in both children. Markedly increased aromatase activity was found in the patients’ fibroblasts and Epstein-Barr virus-transformed lymphocytes. The P450arom polymorphism segregated with the disease in the family. A new 5′-splice variant was present in the patients’ P450arom messenger ribonucleic acid, thus identifying yet another first exon of this gene, which appears to be aberrantly expressed in this family.

In conclusion, a family with the aromatase excess syndrome is described, in which the condition was inherited in an autosomal dominant manner, led to feminizing manifestations in both sexes, and was associated with the aberrant utilization of a novel transcript of the P450arom gene.
The Impact of Reversible Gonadal Sex Steroid Suppression on Serum Leptin Concentrations in Children with Central Precocious Puberty1
Authors: Palmert Mark R. , Radovick Sally , Boepple Paul A.
Published: January 2014

Serum leptin concentrations increase during childhood in both sexes. During sexual maturation, levels rise further in girls, but decrease in boys. These data suggest that testosterone either directly suppresses leptin levels or induces changes in body composition that result in lower leptin concentrations.

To examine further the relationship between sex steroids and leptin, we performed a longitudinal study in children with central precocious puberty (28 girls and 12 boys) before, during, and after discontinuation of GnRH agonist-induced pituitary-gonadal suppression. Nighttime and daytime leptin levels were measured to determine whether the activity of the pituitary-gonadal axis affects their diurnal variation.

In the boys, suppression of testosterone increased leptin levels, whereas resumption of puberty was associated with decreased leptin levels [3.5 ± 0.8 vs. 9.5 ± 3.1 ng/dL (P = 0.005) and 12.2 ± 4.5 vs. 7.0 ± 2.6 ng/dL (P = 0.012), respectively]. Serum leptin levels did not change in the girls with alteration of the pituitary-ovarian axis and consistently exceeded those in boys. Nighttime levels were consistently greater than daytime values by an average of 38.3% in the girls and 29.4% in the boys.

These serial observations during reversible pituitary-gonadal suppression suggest that testosterone decreases leptin concentrations, but that estrogen, at least in this childhood model, has no discernible effect. In addition, our data indicate that the presence of the diurnal rhythm in leptin concentrations is independent of the state of the reproductive axis.
Effect of Glucose on Production and Release of Proinsulin Conversion Products by Cultured Human Islets1
Authors: Zambre Yasmeeni , Ling Zhidong , Hou Xue , Foriers Andre , Van Den Bogaert Bas , Van Schravendijk Chris , Pipeleers Daniel
Published: January 2014

Isolated human islets were examined for the rates of conversion and release of newly formed (pro)insulin-like peptides. The rate of proinsulin (PI) conversion was 2-fold slower in human β-cells (t1/2 = 50 min) than in rat β-cells (t1/2 = 25 min). During the first hour following labeling of newly synthesized proteins, PI represented the main newly formed hormonal peptide in the medium; its release was stimulated 2-fold over the basal level by 20 mmol/L glucose. During the second hour, newly synthesized hormone was mainly released as insulin, with 10- to 20-fold higher rates at 20 mmol/L glucose. Prolonged preculture of the islets at 20 mmol/L glucose did not delay PI conversion, but markedly increased the release of newly formed PI, des31,32-PI, and insulin at both low and high glucose levels. Our data demonstrate that 1) the release of PI provides an extracellular index for the hormone biosynthetic activity of human β-cells; 2) an acute rise in glucose exerts a stronger amplification of the release of converted hormone than in that of nonconverted hormone; and 3) prolonged exposure to high glucose levels results in an elevated basal release of converted and nonconverted PI; this elevation is not associated with a delay in PI conversion, but is attributed to the hyperactivated state of the human β-cell population, which was recently found to be responsible for an elevation in basal rates of hormone synthesis. These in vitro observations on human β-cells provide a possible explanation for the altered circulating (pro)insulin levels measured in nondiabetic and noninsulin-dependent diabetic subjects.
Decline in Insulin-Like Growth Factor I Levels after Clomiphene Citrate Does Not Correct Hyperandrogenemia in Polycystic Ovary Syndrome
Authors: Fiad Tarek M. , Smith Thomas P. , Cunningham Sean K. , McKenna T. Joseph
Published: January 2014

It is widely accepted that the action of clomiphene citrate (CC) is mediated through its antiestrogenic properties on the hypothalamic-pituitary axis. Although insulin-like growth factor I (IGF-I) enhances the thecal cell response to LH, and estrogen treatment is associated with a reduction in IGF-I levels, CC is known to decrease circulatory IGF-I levels in polycystic ovary syndrome (PCOS) patients. The impact of lowering IGF-I levels on androgen levels in PCOS is unknown. This study was designed to examine the impact of CC treatment on the interrelationships of IGF-I, androgens, and estrogens in normal subjects and patients with PCOS. IGF-I, gonadotropin, androgen, estrogen, and sex hormone-binding globulin levels were measured in 8 PCOS patients and 10 normal subjects before and after treatment with the antiestrogen CC. Studies were performed in the early follicular phase, days 4–6 of the menstrual cycle in normal subjects. In normal subjects, CC treatment led to a significant increase in estradiol (84 ± 10 to 234 ± 62 pmol/L, untreated and CC treated; P < 0.05) and estrone (125 ± 14 to 257± 29 pmol/L; P < 0.05) levels with a significant lowering of IGF-I levels (297 ± 25 to 230 ± 17 μg/L; P < 0.05). Similarly, in PCOS patients a significant increase in estradiol (110 ± 11 to 245 ± 58 pmol/L; P < 0.05) and estrone (301 ± 32 to 401 ± 90 pmol/L; P < 0.05) levels and a significant lowering of IGF-I levels (330 ± 43 to 214 ± 27μ g/L; P < 0.05) were observed after CC treatment. However, no significant correlation was observed between changes in IGF-I and changes in estradiol in either group. Compared to pretreatment levels, no significant changes in the following parameters were observed after 5 days of CC treatment in either study group: testosterone, testosterone/sex hormone-binding globulin ratio, and androstenedione.

The relationship among CC treatment, gonadotropin, estrogen, and IGF-I levels is complex. Changes in blood IGF-I levels are not associated with changes in androgen levels, although paracrine and or autocrine effects cannot be excluded.
Retinal Changes Mimicking Diabetic Retinopathy in Two Nondiabetic, Growth Hormone-Treated Patients1
Authors: Koller Elizabeth Ann , Green Lanh , Gertner Joseph Michael , Bost Michel , Malozowski Saul Norberto
Published: January 2014

A role for GH in the pathogenesis of diabetic retinopathy has long been postulated. Previous clinical studies, however, have been confounded by hyperglycemia. We have identified 2 cases of retinopathy associated with exogenous GH therapy in nondiabetic patients. Cases were identified through the MedWatch drug surveillance system of the U.S. Food and Drug Administration. Causality by concomitant medications was excluded by a search of the literature and the FDA data base. The first patient, an obese, 31-yr-old male with traumatic hypothalamic injury, presented with nonproliferative retinopathy and macular edema, resulting in decreased visual acuity (OD 20/40–1; OS count fingers), which required laser surgery. Human GH had been initiated at 0.009 mg/kg·day, 14 months earlier, and titrated to 0.017 mg/kg·day. The second patient, a nonobese, 11-yr-old girl receiving GH for the management of short stature in Turner’s Syndrome, presented with neovascularization. GH doses were 0.033 mg/kg·day for the first 17 months and 0.043 mg/kg·day for the following 5 months. Cumulative laboratory and clinical observations suggest that GH and related peptides have a role in retinal pathology independent of the degree of glucose tolerance.
Improved Diagnostic Accuracy of Inferior Petrosal Sinus Sampling over Imaging for Localizing Pituitary Pathology in Patients with Cushing’s Disease
Authors: Booth Gillian L. , Redelmeier Donald A. , Grosman Harvey , Kovacs Kalman , Smyth Harley S. , Ezzat Shereen
Published: January 2014

The majority of patients with Cushing’s disease can be cured by transsphenoidal microsurgery; however, precise localization of the pituitary source of ACTH is not always possible by standard imaging techniques. Bilateral venous sampling from the inferior petrosal sinuses (IPSS) is also useful for diagnosing Cushing’s disease, but the interpretation of discordant findings between IPSS and imaging remains problematic. We tested the ability of imaging and IPSS to localize an ACTH-secreting pituitary lesion in comparison to definitive histopathological examination of the pituitary in patients with Cushing’s disease (n = 37). Bilateral IPS catheterization was technically feasible in 32 patients and provided evidence of lateralization in 31 patients. Histological examination confirmed a corticotropic adenoma in 28 patients and corticotropic hyperplasia in 2 patients; Crooke’s hyaline change was found in 7 patients, among whom 1 subsequently was found to have an ectopic sphenoid corticotropic adenoma, and the remainder had suspected microadenomas that were not identified microscopically. Accurate localization of the pituitary lesion was more frequent when based on IPSS results than on imaging studies (70% vs. 49%, P < 0.06). The 2 tests provided directly discrepant results for 8 patients; among these, IPSS was more likely than imaging to agree with final pathology (63% vs. 13%, P < 0.10). Imaging was entirely normal for another 9 patients, in whom IPSS accurately localized the lesion for the majority (89%; 95% confidence interval: 50–99%). We suggest that IPSS is an effective tool for localizing pituitary pathology and planning surgery for patients with Cushing’s disease.
Concentration of Insulin-Like Growth Factor (IGF)-I and -II in Iliac Crest Bone Matrix from Pre- and Postmenopausal Women: Relationship to Age, Menopause, Bone Turnover, Bone Volume, and Circulating IGFs1
Authors: Seck Thomas , Scheppach Beate , Scharla Stefan , Diel Ingo , Blum Werner F. , Bismar Hanadi , Schmid Gerald , Krempien Burkhard , Ziegler Reinhard , Pfeilschifter Johannes
Published: January 2014

Insulin-like growth factor-I (IGF-I) and -II are important local regulators of bone metabolism, but their role as determinants of human bone mass is still unclear. In the present study, we analyzed the concentration of IGF-I and -II in the bone matrix of 533 human biopsies from the iliac crest that were obtained during surgery for early breast cancer. There was an inverse association of bone matrix IGF-I concentration with age that was unaffected by menopause. Bone matrix IGF-I was positively associated with histomorphometric and biochemical parameters of bone formation and bone resorption and with cancellous bone volume. Based on the estimates of the linear regression analysis, women with a bone matrix IGF-I concentration 2 sd above the mean had a 20% higher bone volume than women with a bone matrix IGF-I concentration 2 sd below the mean. In contrast, serum IGF-I was neither correlated with bone turnover nor with bone volume and was only weakly associated with bone matrix IGF-I when adjusted for the serum concentration of IGF binding protein-3. Bone matrix IGF-II was positively associated with the osteoblast surface, but in contrast to IGF-I, tended to be positively associated with age and was unrelated to cancellous bone volume.

In summary, our study suggests the following. 1) The concentration of IGF-I in cancellous bone undergoes age-related decreases that are similar to those of circulating IGF-I. 2) Menopause has no effect on this age-related decline. 3) Physiological differences in bone matrix IGF-I are associated with differences in iliac crest cancellous bone volume. 4) Bone matrix IGF-I is a better predictor of cancellous bone volume than circulating IGF-I. 5) The role of IGF-II in human bone tissue is clearly distinct from that of IGF-I.
Iodide Symporter Gene Expression in Human Thyroid Tumors1
Authors: Arturi Franco , Russo Diego , Schlumberger Martin , du Villard Jean-Antoine , Caillou Bernard , Vigneri Paolo , Wicker René , Chiefari Eusebio , Suarez Horacio G. , Filetti Sebastiano
Published: January 2014

Expression of the Na+/I− symporter (NIS) gene was investigated by RT-PCR in a selected series of 26 primary thyroid carcinomas (19 papillary, 5 follicular, and 2 anaplastic). Fifteen follicular adenomas (11 “cold ” and 4 “hot” adenomas) were also studied. Five of 19 papillary thyroid cancer did not express NIS messenger ribonucleic acid (mRNA). In all but 1 follicular cancer, NIS transcript was fully detected. In anaplastic tissue, NIS mRNA was only barely detected in 1 case. All of the follicular thyroid adenomas except 1 expressed the NIS gene. In contrast, all tumors studied excluding the anaplastic histotype fully expressed thyroglobulin and thyroid peroxidase mRNA transcripts. In 2 patients, a lower expression (3- to 5-fold) of NIS mRNA was found in metastasis by dot blot analysis compared with those in both normal and primary neoplastic thyroid tissue. Four of 8 differentiated thyroid cancer patients selected for the presence of metastases with negative posttherapy 131I total body scan showed the lack of NIS gene expression in their primary cancer. This defect, at least in these cases, is a somatic and intrinsic lesion of the primary cancer cells and is not due to a dedifferentiation process in the metastatic tissue. The early detection of the loss of NIS gene expression in the primary cancer, therefore, may provide useful information for the management of differentiated thyroid cancer patients.
Molecular Screening of Uncoupling Protein 2 Gene in Patients with Noninsulin-Dependent Diabetes Mellitus or Obesity1
Authors: Kubota Takanori , Mori Hiroyuki , Tamori Yoshikazu , Okazawa Hideki , Fukuda Tsuneo , Miki Masatoshi , Ito Chikako , Fleury Christophe , Bouillaud Frédéric , Kasuga Masato
Published: January 2014

abstract

Uncoupling protein 2 (UCP2), a member of the family of mitochondrial carrier proteins, has been implicated in the control of whole-body energy balance. The coding region of the human UCP2 gene has now been shown to comprise six exons, and the sequences of the exon-intron boundaries were determined. With the use of this sequence information, 25 Japanese patients with obesity and noninsulin-dependent diabetes mellitus (NIDDM) and 25 subjects with simple obesity were screened for mutations in the entire coding region of UCP2 by PCR and single-strand conformation polymorphism analysis. Two nucleotide polymorphisms resulting in Ala55 → Val and Ala232 → Thr substitutions were detected. With the use of PCR and restriction fragment length polymorphism analysis, the allele frequencies for each of these polymorphisms were determined in 210 Japanese patients with NIDDM, 42 obese individuals, and 218 normal control subjects. The frequency of the Val55 allele did not differ significantly among the NIDDM group (46.0%), the obesity group (48.8%), and the normal control group (48.4%). The Thr232 allele was detected in only three subjects, who were heterozygotes and in the NIDDM group (allele frequency, 0.7%). However, expression in yeast of the human wild-type UCP2 protein and UCP2 containing Thr232 revealed no difference in functional activity. These results indicate that the Ala55 → Val and Ala232 → Thr variants of UCP2 do not play an important role in the pathogenesis of NIDDM or obesity in the Japanese population.
Mechanisms of Whole-Body Glycogen Deposition after Oral Glucose in Normal Subjects. Influence of the Nutritional Status1
Authors: Féry F. , Plat L. , Balasse E. O.
Published: January 2014

abstract

It is known that prior fasting enhances whole-body glycogen retention after glucose ingestion. To identify the involved mechanisms, 33 normal volunteers underwent a total fast, varying between 14 h and 4 days, and ingested thereafter 75 g glucose labeled with[ 14C]-glucose. Measurements of oral glucose oxidation (expired 14CO2, corrected for incomplete recovery) and total carbohydrate (CHO) oxidation (indirect calorimetry) were performed over the following 5 h. These data allowed us to calculate oral glucose storage (uptake − oxidation), glycogen oxidation (CHO oxidation − oral glucose oxidation), and net CHO balance (oral glucose uptake − CHO oxidation). As compared with an overnight fast, prolonged fasting (4 days) inhibited the uptake (64.8 vs. 70.3 g/5 h; P < 0.01) and the oxidation (10.9 vs. 20.0 g/5h; P< 0.001) of oral glucose and stimulated slightly its conversion to glycogen (53.9 vs. 50.3 g/5 h; P < 0.05). The latter effect played only a minor role in the marked increase in net CHO balance (52.3 vs. 25.2 g/5 h; P < 0.001), which was almost entirely related to a decrease in glycogen oxidation (1.6 vs. 25.1 g/5 h; P < 0.001). Considering the whole series of data, including intermediate durations of fast, it was observed that the modifications in postprandial CHO metabolism, induced by fasting, correlated strongly with basal CHO oxidation, suggesting that the degree of initial glycogen depletion is a major determinant of glycogen oxidation and net CHO storage. Thus, prior fasting stimulates postprandial glycogen retention, mainly through an inhibition of the glycogen turnover that exists in overnight-fasted subjects, during the absorptive period.
Congenital Adrenal Hypoplasia: Clinical Spectrum, Experience with Hormonal Diagnosis, and Report on New Point Mutations of the DAX-1 Gene
Authors: Peter Michael , Viemann Matthias , Partsch Carl-Joachim , Sippell Wolfgang G.
Published: January 2014

abstract

X-linked congenital adrenal hypoplasia (AHC) is a rare developmental disorder of the human adrenal cortex and is caused by deletion or mutation of the DAX-1 gene, a recently discovered member of the nuclear hormone receptor superfamily. Hypogonadotropic hypogonadism is frequently associated with AHC. AHC occurs as part of a contiguous gene syndrome together with glycerol kinase deficiency (GKD) and Duchenne’s muscular dystrophy. The present series, collected over the past 2 decades, includes 18 AHC boys from 16 families: 4 with AHC, GKD, and Duchenne’s muscular dystrophy; 2 with AHC and GKD; and 12 with AHC (5 young adults with hypogonadotropic hypogonadism). Most of the boys presented with salt wasting and hyperpigmentation during the neonatal period. Plasma steroid determinations performed in the first weeks of life often showed confusing results, probably caused by steroids produced in the neonates’ persisting fetocortex. Aldosterone deficiency usually preceded cortisol deficiency, which explains why the patients more often presented with salt-wasting rather than with hypoglycemic symptoms. An ACTH test was often necessary to detect cortisol deficiency in the very young infants. In some patients, serial testing was necessary to establish the correct diagnosis. In 4 boys studied during the first 3 months after birth, we found pubertal LH, FSH, and testosterone plasma levels indicating postnatal transient activation of the hypothalamic-pituitary-gonadal axis as in normal boys. Previous studies have shown that the DAX-1 gene is deleted in the AHC patients with a contiguous gene syndrome and is mutated in nondeletion patients. Most of the point mutations identified in AHC patients were frameshift mutations and stop mutations. In the 15 patients available for molecular analysis of the DAX-1 gene, there were large deletions in 6 patients and point mutations in another 7 patients. All of the point mutations identified in the present study resulted in a nonfunctional truncated DAX-1 protein. Two brothers with primary adrenal insufficiency and a medical history that strongly suggested AHC had no mutation in the DAX-1 gene. Thus, additional, as yet unknown genes must play a part in normal adrenal cortical development.
Recovery of Growth Hormone Release from Suppression by Exogenous Insulin-Like Growth Factor I (IGF-I): Evidence for a Suppressive Action of Free Rather Than Bound IGF-I1
Authors: Chapman Ian M. , Hartman Mark L. , Pieper Karen S. , Skiles Emily H. , Pezzoli Suzan S. , Hintz Raymond L. , Thorner Michael O.
Published: January 2014

abstract

To determine the time course of recovery of GH release from insulin-like growth factor I (IGF-I) suppression, 11 healthy adults (18–29 yr) received, in randomized order, 4-h iv infusions of recombinant human IGF-I (rhIGF-I; 3 μg/kg·h) or saline (control) from 25.5–29.5 h of a 47.5-h fast. Serum GH was maximally suppressed within 2 h and remained suppressed for 2 h after the rhIGF-I infusion; during this 4-h period, GH concentrations were approximately 25% of control day levels [median (interquartile range), 1.2 (0.4–4.0) vs. 4.8 (2.8–7.9) μg/L; P < 0.05]. A rebound increase in GH concentrations occurred 5–7 h after the end of rhIGF-I infusion [7.6 (4.6–11.7) vs. 4.3 (2.5–6.0) μg/L; P < 0.05]. Thereafter, serum GH concentrations were similar on both days. Total IGF-I concentrations peaked at the end of the rhIGF-I infusion (432 ± 43 vs. 263 ± 44 μg/L; P < 0.0001) and remained elevated 18 h after the rhIGF-I infusion (360 ± 36 vs. 202 ± 23 μg/L; P = 0.001). Free IGF-I concentrations were approximately 140% above control day values at the end of the infusion (2.1 ± 0.4 vs. 0.88 ± 0.3 μg/L; P = 0.001), but declined to baseline within 2 h after the infusion. The close temporal association between the resolution of GH suppression and the fall of free IGF-I concentrations, and the lack of any association with total IGF-I concentrations suggest that unbound (free), not protein-bound, IGF-I is the major IGF-I component responsible for this suppression. The rebound increase in GH concentrations after the end of rhIGF-I infusion is consistent with cessation of an inhibitory effect of free IGF-I on GH release.
Vitamin K Status and Bone Health: An Analysis of Methods for Determination of Undercarboxylated Osteocalcin1
Authors: Gundberg Caren M. , Nieman Sherril D. , Abrams Steven , Rosen Harold
Published: January 2014

Recent studies suggest that fracture risk is associated with increased undercarboxylated osteocalcin. Methods use differences in binding of undercarboxylated and fully carboxylated osteocalcin to hydroxyapatite or barium sulfate. We evaluated these methods and found that results varied with the amount and preparation of the salts. Furthermore, patient samples with differing amounts of total osteocalcin could not be directly compared. Errors in the determination of undercarboxylated osteocalcin were minimized by expressing data as the percent of the total osteocalcin in the sample, and correcting for the basal level of osteocalcin using a polynomial equation derived from multiple binding curves. Errors from 5–15% in estimation of undercarboxylated osteocalcin were observed without both of these corrections. When differing types of assays were employed (RIA, intact, N-terminal), results also were affected. In normal adults and children and in patients on long-term warfarin therapy, the percent osteocalcin not bound to hydroxyapatite was lower when measured with an intact assay than by a polyclonal RIA. Differences were related to the amount of N-terminal osteocalcin fragments, which had low affinity for hydroxyapatite and resulted in variable overestimation of undercarboxylated osteocalcin.

In a kit specific for uncarboxylated osteocalcin, we found good discrimination between carboxylated and uncarboxylated intact osteocalcin. However, the assay detected large osteocalcin fragments and overestimated their concentration by up to 350%. Values for uncarboxylated osteocalcin were not different in patients on coumadin compared with normal adults with this kit, but when normalized to the total intact osteocalcin, percent uncarboxylated osteocalcin was greater in patients on coumadin than in controls, as would be expected. Kit values for uncarboxylated osteocalcin in normal children were higher than intact values in the same subject, because of the increased reactivity of the kit toward circulating fragments that were elevated in children.

Thus, for estimation of undercarboxylated osteocalcin, care must be taken to standardize the hydroxyapatite or barium sulfite used for binding, to correct for the basal level of osteocalcin in the sample, to use immunoassays that do not detect small fragments, and to express the results as the percent of the total osteocalcin in the sample. Without these precautions, the assessment of undercarboxylated osteocalcin is not reliable.
Plasma Adrenal, Gonadal, and Conjugated Steroids before and after Long Term Overfeeding in Identical Twins1
Authors: Pritchard Janet , Després Jean-Pierre , Gagnon Jacques , Tchernof André , Nadeau André , Tremblay Angelo , Bouchard Claude
Published: January 2014

An analysis of the data collected in the Quebec Overfeeding Study of identical twins was undertaken to determine any evidence of a genotype effect on plasma levels of adrenal and gonadal steroids arising from long term positive energy balance. Plasma levels of sex hormone-binding globulin (SHBG), testosterone, dihydrotestosterone (DHT), dehydroepiandrosterone sulfate (DHEA-S), androsterone glucuronide, androstane-3α,17β-diol glucuronide (3α-DIOL-G), and cortisol were measured in 12 pairs of young, sedentary, male monozygotic twins before and after 100 days of overfeeding. The dietary energy excess of 4.2 MJ/day (1000 Cal), 6 days a week, resulted in a total positive energy balance of 353 MJ (84,000 Cal). Overfeeding induced significant changes (P < 0.0001) in body weight and other measures of body composition. Within-twin pair resemblance was observed at baseline in all steroids, except cortisol [intraclass correlation range: DHEA-S, 0.50 (P < 0.05); DHT, 0.77 (P < 0.001)] and was lost with overfeeding, except for DHT and SHBG (P < 0.05). SHBG levels fell and 3α-DIOL-G rose with the gain in body fatness. The change in testosterone was a significant correlate of the change in upper body fat (r = −0.48; P < 0.05). The change in 3α-DIOL-G correlated positively with increases in all measures of central adiposity (r = 0.52; P < 0.01). A decrease in DHEA-S occurred with a higher, but not with a lower, gain in abdominal visceral fat (P < 0.05). Thus, analysis of adrenal and gonadal steroids and of conjugated metabolites before and after overfeeding in monozygous twins supports the idea that there is a genotype effect on steroid circulating steroid levels and that these blood levels are correlated with the pattern of body fat distribution. Moreover, the baseline within-twin pairs similarity in steroid levels was attenuated by prolonged positive energy balance and body fat gain.
Titrating Luteinizing Hormone Replacement to Sustain the Structure and Function of the Corpus Luteum after Gonadotropin-Releasing Hormone Antagonist Treatment in Rhesus Monkeys1
Authors: Duffy Diane M. , Stewart Dennis R. , Stouffer Richard L.
Published: January 2014

These studies were designed to identify 1) a regimen of a third generation GnRH antagonist that abolishes primate luteal function, and 2) the amount of LH replacement required to maintain the structure and functional life span of the corpus luteum of the menstrual cycle after GnRH antagonist treatment. A single injection of antide at 3 or 5 mg/kg BW on day 6 of the luteal phase suppressed serum progesterone levels within 1 day of treatment, but levels recovered within 4 days. Administration of antide (3 mg/kg) for 3 days (luteal days 6–8) reduced (P < 0.05) serum progesterone below 1 ng/mL and maintained these low levels for the entire sampling period; in subsequent experiments, all monkeys received this antide regimen. Fixed doses (5, 10, or 20 IU) of recombinant human LH administered at 8-h intervals during and after antide treatment stimulated progesterone production in a dose-dependent manner; these monkeys menstruated earlier than controls regardless of treatment group. Replacement with an escalating dose regimen (5–20 IU) of LH resulted in typical serum progesterone and relaxin levels throughout a luteal phase of normal length. Corpora lutea removed on day 10 from monkeys treated with antide alone had decreased wet weight (P < 0.05) and few large luteal cells; coadministration of the escalating dose regimen of LH maintained luteal structure similar to that seen in time-matched controls. Antide-only treatment increased progesterone receptor (PR) messenger ribonucleic acid, but decreased PR immunostaining in luteal tissue; the escalating dose regimen of LH maintained PR messenger ribonucleic acid and immunostaining similar to those in controls. This study indicates that during GnRH antagonist administration, an escalating dose regimen of LH replacement is optimal for maintenance of the structure and functional life span of the primate corpus luteum.
Adrenocorticotropin Responses to Naloxone in Sons of Alcohol-Dependent Men1
Authors: Wand Gary S. , Mangold Deborah , Ali Mahmood
Published: January 2014

The endogenous opioid system is part of a neural circuitry functionally related to alcohol-seeking behaviors. A family history of alcoholism is the strongest predictor of future development of alcohol dependence. This study was designed to evaluate ACTH responses to opioid receptor blockade as a function of family history for alcohol dependence. The nonselective opioid antagonist naloxone stimulates ACTH secretion by blocking opioidergic input on paraventricular corticotropin-releasing factor neurons, thereby providing a methodology for comparing hypothalamic opioid tone between study groups. Sixty nonalcoholic subjects, aged 18–25 yr, were enrolled in a protocol to measure the ACTH response to naloxone. Thirty-two subjects were offspring from families with a high density of alcohol dependence and were designated as family history-positive subjects. Twenty-eight subjects were offspring of nonalcohol-dependent parents and were designated family history-negative subjects. Subjects received naloxone (125 μg/kg) or placebo (0.9% saline) in double blind, randomized order. Plasma ACTH was monitored. Family history-positive men had increased ACTH response to naloxone compared to 1) family history-positive women, 2) family history-negative men, and 3) family history-negative women. Despite differences in plasma ACTH levels after naloxone administration, plasma naloxone concentrations did not differ between study groups. This finding suggests that nonalcoholic male offspring of alcohol-dependent men have altered endogenous opioid activity directed at hypothalamic corticotropin-releasing factor neurons.
Microsatellite Polymorphism of the MHC Class I Chain-Related (MIC-A and MIC-B) Genes Marks the Risk for Autoimmune Addison’s Disease
Authors: Gambelunghe Giovanni , Falorni Alberto , Ghaderi Mehran , Laureti Stefano , Tortoioli Cristina , Santeusanio Fausto , Brunetti Paolo , Sanjeevi Carani B.
Published: January 2014

The major histocompatibility complex class I chain-related MIC-A and MIC-B genes are located on chromosome 6 between the histocompatibility leucocyte antigen (HLA)-B and the B-associated transcript genes. The presence of 21-hydroxylase autoantibodies is a sensitive and specific marker of autoimmune Addison’s disease. We studied the polymorphism of exon 5 of the MIC-A gene, of intron 1 of the MIC-B gene, and of HLA-DRB1, -DQA1, and -DQB1 genes in 28 autoimmune (21-hydroxylase autoantibody positive) Addison’s disease patients and in 75 healthy subjects from central Italy. The MIC-A5.1 allele was significantly more frequent in Addison’s disease patients (79%) than in healthy subjects (36%) [odds ratio (OR) = 6.52, corrected P (Pc) = 0.0015], whereas MIC-A6 was significantly reduced in affected subjects (15% vs. 56%, OR = 0.13, Pc = 0.002). The A5.1/A5.1 genotype had an OR for autoimmune Addison’s disease as high as 18.0 and an absolute risk of 1 per 1131. In the presence of MIC-A5.1, MICB-CA-25 was significantly increased in Addison’s disease patients (25% vs. 4%, OR = 8.0, P = 0.0039, Pc = 0.047). The MICB-CA-17 allele was absent in Addison’s disease patients, but present in more than 25% healthy individuals (OR = 0.10, P = 0.0025, Pc = 0.03). Among HLA-DR and -DQ haplotypes, only DRB1*03-DQA1*0501-DQB1*0201 (DR3/DQ2) was significantly more frequent in Addison’s disease patients than in healthy subjects, but only in the presence of MIC-A5.1. The frequency of MIC-A5.1 was significantly increased in Addison’s disease patients only in the presence of HLA-DR3-DQ2. Our study demonstrates that susceptibility to autoimmune Addison’s disease is linked to the MIC-A microsatellite allele 5.1 and that both MIC-A5.1 and HLA-DR3/DQ2 are necessary to confer increased genetic risk for Addison’s disease.
The Interaction of TSH Receptor Autoantibodies with 125I-Labelled TSH Receptor
Authors: Sanders Jane , Oda Yasuo , Roberts Sara , Kiddie Angela , Richards Tonya , Bolton Jane , McGrath Vivienne , Walters Susannah , Jaskólski Donat , Furmaniak Jadwiga , Smith Bernard Rees
Published: January 2014

Detergent-solubilized porcine TSH receptor (TSHR) has been labeled with 125I using a monoclonal antibody to the C-terminal domain of the receptor. The ability of sera containing TSHR autoantibody to immunoprecipitate the labeled receptor was then investigated. Sera negative for TSHR autoantibody (as judged by assays based on inhibition of labeled TSH binding to detergent-solubilized porcine TSHR) immunoprecipitated about 4% of the labeled receptor, whereas sera with high levels of receptor autoantibody immunoprecipitated more than 25% of the labeled receptor. The ability to immunoprecipitate labeled TSHR correlated well with ability of the sera to inhibit labeled TSH binding to the receptor (r = 0.92; n = 63), and this is consistent with TSHR autoantibodies in these samples being directed principally to a region of the receptor closely related to the TSH binding site. Preincubation of labeled TSHR with unlabeled TSH before reaction with test sera inhibited the immunoprecipitation reaction, providing further evidence for a close relationship between the TSHR autoantibody binding site(s) and the TSH binding site. This was the case whether the sera had TSH agonist (i.e., thyroid stimulating) or TSH antagonist (i.e., blocking) activities, thus, providing no clear evidence for different regions of the TSHR being involved in forming the binding site(s) for TSHR autoantibodies with stimulating and with blocking activities. The ability of TSHR autoantibodies to stimulate cyclic AMP production in isolated porcine thyroid cells was compared with their ability to immunoprecipitate labeled porcine TSHR. A significant correlation was observed (r = 0.58; n = 50; P < 0.001) and the correlation was improved when stimulation of cyclic AMP production was compared with inhibition of labeled TSH binding to porcine TSHR (r = 0.76). Overall, our results indicate that TSHR autoantibodies bind principally to a region on the TSHR closely related to the TSH binding site, and this seems to be the case whether the autoantibodies act as TSH agonists or antagonists.
Effects of Postnatal Estradiol and Progesterone Replacement in Extremely Preterm Infants
Authors: Trotter Andreas , Maier Ludwig , Grill Hans-Jörg , Kohn Thomas , Heckmann Matthias , Pohlandt Frank
Published: January 2014

The fetus is supplied from the placenta with estradiol (E2) and progesterone (P) in increasing amounts during gestation. After delivery of a premature infant, placental supply is disrupted, resulting in a rapid decrease in E2 and P. Replacement of these placental hormones may restore intrauterine conditions and may be beneficial for bone mineral accretion, clinical course, and outcome. Thirty female infants with a median gestational age of 26.6 weeks (between 24.1–28.7) and a birth weight of 675 g (370–990) were randomized to receive E2 and P replacement, aiming to maintain plasma levels equaling the intrauterine levels, or no replacement. The E2 and P replacement was started iv and was followed by transepidermal administration for a total duration of 6 weeks. Repeated measurements included plasma levels of E2, P, FSH, and LH; uterine volume; calcium and phosphorus in spot urine specimens; and bone mineral accretion by single photon absorption densitometry. Further, the incidence of chronic lung disease and various clinical outcome data were recorded. The plasma levels of E2 and P were within the intrauterine range with median replacements of 2.30 mg/kg·day E2 (1.13–6.23) and 21.20 mg/kg·day P (11.23–27.36), iv. Three- and 6-fold higher doses of E2 and P were needed via the transepidermal route. The uterine volumes increased, and FSH and LH as indicators for biological effectiveness were significantly lowered with replacement. The bone mineral accretion rates tended to be higher, and the incidence of chronic lung disease tended to be lower (0% vs. 29%; P = 0.097). E2 and P replacement via iv and transepidermal routes is capable of maintaining plasma levels as high as those in utero with biological effectiveness. Trends toward improved postnatal bone mineral accretion and less chronic lung disease were found with the hormone replacement. Further and more extensive studies are warranted to address the role of this new approach in the care of extremely premature infants.