bluuebunny/crossref_metadata_2025_split huggingface dataset:
Serum levels of β-subunit of chorionic gonadotropin in patients with pituitary tumors
Authors: Gil-del-Alamo Paloma , Saccomanno Katia , Lania Andrea , Pettersson Kim SI , Beck-Peccoz Paolo , Spada Anna 
Published: December 2008

Gil-del-Alamo P, Saccomanno K, Lania A, Pettersson KSI, Beck-Peccoz P, Spada A. Serum levels of β-subunit of chorionic gonadotropin in patients with pituitary tumors. Eur J Endocrinol 1995;133:33–7. ISSN 0804–4643
Many studies have shown that normal and tumoral pituitary is able to synthesize chorionic gonadotropin (CG). The aim of the present work was to investigate the circulating levels of free β-subunit of CG (CG-β) in a large number of patients with pituitary tumors in basal conditions and after thyrotropin-releasing hormone (TRH) injection. The study includes 27 healthy subjects, 23 patients with prolactinoma, 20 with growth hormone-secreting adenoma and 77 with non-functioning pituitary adenoma (NFPA). The CG-β was evaluated using a new one-step immunometric assay employing two monoclonal antibodies directed against epitopes present only on the free CG-β and showing a detection limit of 0.04 U/l and a cross-reactivity with complete CG < 0.01%. In basal conditions, serum CG-β was undetectable in healthy subjects and in the majority of patients, while in seven patients with NFPA and four with prolactinoma the CG-β values ranged between 0.05 and 0.72 U/l. In these 11 patients serum levels of intact CG were found within the normal range (normal range < 5 U/I), while two patients with NFPA and one with prolactinoma had levels of free α-subunit inappropriately high with respect to gonadotropins and thyrotropin. Injection of TRH caused CG-β to increase in two out of 16 patients with NFPA, whereas it was ineffective in 12 healthy subjects and 10 patients with prolactinoma. The present data indicate that detectable level of CG-β not associated with hypersecretion of the intact CG molecule may be observed in about 10% of patients with NFPA or prolactinoma, while abnormal CG-β responses to TRH are observed infrequently in individual patients with NFPA.
Paolo Beck-Peccoz, Institute of Endocrine Sciences, Ospedale Maggiore IRCCS, Pad. Granelli, Via F Sforza 35, 20122-Milano, Italy
Technetium-99m pentavalent dimercaptosuccinic acid imaging in patients with pituitary adenomas
Authors: Lastoria Secondo , Colao Annamaria , Vergara Emilia , Ferone Diego , Varrella Paola , Merola Bartolomeo , Lombardi Gaetano , Salvatore Marco 
Published: December 2008

Lastoria S, Colao A, Vergara E, Ferone D, Varrella P, Merola B, Lombardi G, Salvatore M. Technetium-99m pentavalent dimercaptosuccinic acid imaging in patients with pituitary adenomas. Eur J Endocrinol 1995;133:38–47. ISSN 0804–4643
We studied the tumor-seeking agent technetium-99m-labeled pentavalent dimercaptosuccinic acid ([99mTc](V)DMSA) to visualize 21 growth hormone (GH)-, nine prolactin (PRL)-, two mixed GH/PRL-, six adrenocorticotropin (ACTH)-secreting and 15 clinically non-functioning pituitary adenomas, three craniopharyngiomas and one dysgerminoma of the sella. All non-adenomas and 31 out of 53 adenomas were studied before treatment: 22 after surgery and/or radiotherapy. Eight cases of acromegaly were studied before and after chronic treatment with octreotide, whereas three cases of acromegaly, one of prolactinoma and two of non-functioning adenoma were imaged before and after adenomectomy. As a control group, 27 patients without any clinical evidence of pituitary adenoma were studied: 10 of them were operated on previously and treated with iodine-131 for metastatic thyroid carcinoma, 10 had brain tumors and the remaining seven patients had functional pituitary hypersecretion (four Klinefelter's syndrome, two primary hypothyroidism and one Addison's disease). The scintigraphy was repeated after testosterone in Klinefelter's syndrome, l-thyroxine in primary hypothyroidism and cortisone administration in Addison's disease. Seventeen GH-secreting (81%), seven PRL-secreting (78%), three ACTH-secreting (50%), 15 non-functioning (100%) and one (50%) mixed adenoma significantly concentrated [99mTc](V)DMSA, showing elevated tumor-to-background (T/B) ratios. The T/B ratios were similar in untreated and surgically treated adenomas (11.2 ± 5.6 vs 11.8 ± 6.2). Radiotherapy significantly lowered the [99mTc](V)DMSA uptake to 5.1 ± 2.8 (p < 0.1 vs untreated patients). Non-adenomatous lesions of the sella turcica did not concentrate [99mTc](V)DMSA in the pituitary as well as brain tumors and 8 out of 10 metastatic thyroid cancers. The treatment with octreotide normalized GH and insulin-like growth factor I levels and reduced [99mTc](V)DMSA from 15.7 ± 4.8 to 13.5 ± 3.9 (p < 0.05). Conversely, adequate substitutive therapy completely inhibited the uptake of the radiotracer in Klinefelter's syndrome, in primary hypothyroidism and in Addison's disease. The [99mTc](V)DMSA scintigraphy showed an overall sensitivity of 81% (43/53) in detecting pituitary adenomas, which was increased to 95% for lesions greater than 10 mm in size. High-quality images with minimal total body radiation were obtained, enabling a good in vivo characterization of viable adenomatous tissue as well as an accurate monitoring of the effects of different therapeutic regimens.
Secondo Lastoria, Department of Nuclear Medicine, National Cancer Institute, Fondazione G Pascale, via M Semmola, 80131 Napoli, Italy
Circadian thyrotropin variations are preserved in normal pregnant women
Authors: Roti Elio , Bartalena Luigi , Minelli Roberta , Salvi Mario , Gardini Eliana , Pistolesi Antonio , Martino Enio , Braverman Lewis E 
Published: December 2008

Roti E, Bartalena L, Minelli R, Salvi M, Gardini E, Pistolesi A, Martino E, Braverman LE. Circadian thyrotropin variations are preserved in normal pregnant women. Eur J Endocrinol 1995;133:71–4. ISSN 0804–4643
Serum thyrotropin (TSH) concentration circadian rhythm is abolished in many endocrine and nonendocrine diseases. In the present study we have measured serum TSH concentration over 24 h every 2 h in second and third trimester pregnant women. During the 24-h period, serum free thyroxine and free triiodothyronine concentrations did not change significantly. In contrast, serum TSH concentrations demonstrated significant circadian variations both in the second and third trimester pregnant women (p<0.02 and p <0.005, respectively). In summary, second and third trimester pregnancy is associated with a normal circadian TSH rhythm.
Elio Roti, Centro per lo Studio, Prevenzione, Diagnosi e Cura delle Tireopatie, University of Parma, via Gramsci 14, 1-43100 Parma, Italy
Oncogenic mutations of α-Gi2 protein are not determinant for human adrenocortical tumourigenesis
Authors: Gicquel Christine , Dib Anne , Bertagna Xavier , Amselem Serge , Le Bouc Yves 
Published: December 2008

Gicquel C, Dib A, Bertagna X, Amselem S, Le Bouc Y. Oncogenic mutations of α-Gi2 protein are not determinant for human adrenocortical tumourigenesis. Eur J Endocrinol 1995:133:166–72. ISSN 0804–4643
Activating mutations of G proteins, which are membrane signal transducers, have been associated recently with the development of various endocrine neoplasms. Mutations of two highly conserved codons, Arg201 and Gin227, in the α-subunit of the Gs protein, the adenylyl cyclase-stimulating protein, were first described in growth hormone-producing pituitary tumours. They resulted in constitutive activation of the αs-subunit by decreasing intrinsic GTPase activity. A similar mutation, affecting codon Arg179 (exon 5) in the α-subunit of the Gi2 protein, the adenylyl cyclase-inhibiting protein, has been described by a single group in ovarian and adrenocortical tumours. We evaluated the frequency of activating mutations in the α-subunit of the Gi2 protein in 18 human adrenocortical tumours. We screened exons 5 (codon Arg179) and 6 (codon Gln205) for mutations by denaturing gradient gel electrophoresis analysis of leucocyte and tumoural DNA. No abnormal migration pattern was found in either exon. The absence of mutation in exon 5, which includes the Arg179 codon, was confirmed in all tumoural DNA by direct sequencing. In conclusion, we did not find any oncogenic mutations in the GTPase domain of the α-subunit of the Gi2 protein in adrenocortical tumours. Thus, the previously oncogenic gip2 mutations do not appear to be determinant for adrenocortical tumourigenesis.
Christine Gicquel, Laboratoire d'Explorations Fonctionnelles Endocriniennes, Hôpital Trousseau, 26 Avenue Arnold Netter, 75012 Paris, France
Glucose induces calcium-dependent and calcium-independent insulin secretion from the pancreatic beta cell line MIN6
Authors: Sakuma Nobuko , Ishikawa San-e , Okada Koji , Miyazaki Jun-ichi , Saito Toshikazu 
Published: December 2008

Sakuma N, Ishikawa S, Okada K, Miyazaki J, Saito T, Glucose induces calcium-dependent and calcium-independent insulin secretion from the pancreatic beta cell line MIN6. Eur J Endocrinol 1995;133:227–34. ISSN 0804–4643
The present study was undertaken to determine whether there are Ca2+-dependent and -independent pathways of glucose-induced insulin secretion from the pancreatic beta cell line MIN6. Glucose at a concentration of 16.7 mmol/l caused marked increases in cellular free calcium [Ca2+]1) and insulin secretion, which depended on glucose metabolism. When cells were pretreated with 20 mmol/l mannoheptulose, an inhibitor of glucokinase, the 16.7 mmol/l glucose induced a rise in [Ca2+]1 and insulin secretion disappeared. Also, l-leucine and l-arginine increased [Ca2+]1 and induced insulin secretion. Under Ca2+-free conditions, insulin release was still induced, without any change in [Ca2+]1, by these three different stimulants. The cumulative values of insulin secretion were 13.7–29.3% of the control, which were significantly less than that in the presence of Ca2+. Cellular alkalinization occurred in response to all these stimulants, irrespective of the presence or absence of Ca2+. Forskolin, a diterpene activator of adenylate cyclase, produced insulin secretion independently of [Ca2+]1, which accompanied cellular alkalinization. Also, a high glucose level increased cellular cyclic AMP (cAMP) production in the presence and absence of Ca2+, and the effect was diminished by approximately 73% in Ca2+-free conditions. These results indicate that a high glucose level stimulates both Ca2+-dependent and -independent insulin secretion from pancreatic beta cells. We suggest that the cAMP production and the cellular alkalinization participate in the Ca2+-independent mechanism.
Nobuko Sakuma, Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical School, 3311-1 Yakushiji Minamikawachi-machi, Tochigi 329-04, Japan
Triiodothyronine-induced changes in proton efflux from rat skeletal muscle in vivo
Authors: Thompson Campbell H , Kemp Graham J , Radda George K 
Published: December 2008

Thompson CH, Kemp GJ, Radda GK. Triiodothyronine-induced changes in proton efflux from rat skeletal muscle in vivo. Eur J Endocrinol 1995;133:260–4. ISSN 0804–4643
Hyperthyroidism is associated with muscle weakness, abnormal aerobic metabolism and increased lactate production. Muscle cell acidification during exercise is reduced, suggesting abnormally increased proton efflux. Using 31P magnetic resonance spectroscopy to measure cell pH and phosphocreatine concentration, we quantified effective proton efflux from rat leg muscle in vivo following 10-Hz sciatic nerve stimulation in seven rats injected with triiodothyronine (T3) for 5 days and in 11 controls. Proton efflux during recovery was sigmoidally pH-dependent in both groups but the initial proton efflux rate did not differ (16 ± 3 mmol·kg−1 · min−1 in treated animals vs 15 ± 1 mmol·kg−1·min−1 in controls), despite a significantly smaller pH change from basal in treated animals (0.60 ± 0.04 vs 0.78 ± 0.03 in controls, p = 0.002). The pH dependence of proton efflux can be characterized by an apparent Km, defined as the pH below basal at which proton efflux rate falls to half its start-of-recovery value. This Km was smaller in the T3-treated group (0.44 ± 0.04 vs 0.59 ± 0.03 in controls, p = 0.02). This suggests an increased affinity for protons by cell membrane proton transport processes such as the sodium–proton antiporter and may explain some of the metabolic changes seen clinically in hyperthyroid skeletal muscle.
CH Thompson, MRC Biochemical and Clinical Magnetic Resonance Unit, Oxford Radcliffe Hospital Trust, Headington, Oxford OX3 9DU, UK
Physiological concentrations of retinoic acid suppress the osteoblastic differentiation of fetal rat calvaria cells in vitro
Authors: Ohishi Keiji , Nishikawa Seiji , Nagata Toshihiko , Yamauchi Noriyuki , Shinohara Hiroyuki , Kido Jun-ichi , Ishida Hiroshi 
Published: December 2008

Ohishi K, Nishikawa S, Nagata T, Yamauchi N, Shinohara H, Kido J, Ishida H. Physiological concentrations of retinoic acid suppress the osteoblastic differentiation of fetal rat calvaria cells in vitro. Eur J Endocrinol 1995;133:335–41. ISSN 0804–4643
The effects of retinoic acid (RA) on osteoblastic differentiation and activity were studied in fetal rat calvaria cells cultured for up to 24 days. Fetal bovine serum used for the experiments was treated with an anion-exchange resin to remove endogenous RA. The depletion of RA in the treated serum was confirmed by high-performance liquid chromatography and tritiated RA tracing. Under the culture conditions employed, the continuous presence of RA for 14 days at 10−9 mol/l or higher decreased both alkaline phosphatase (ALP) activity on day 12 and the number of bone nodules on day 14 in a dose-dependent manner. Short-term (24 h) exposure to RA at 10−8 mol/l, which is a physiological concentration, decreased and increased the levels of ALP and osteopontin mRNA on day 6, respectively. Retinoic acid at 10−8 mol/l also increased the level of osteocalcin mRNA on day 12. However, these effects were not obvious at later stages (days 18 and 24). At a high concentration (10−6 mol/l). RA increased the level of osteopontin mRNA on day 6 and decreased the levels of ALP and osteocalcin mRNA irrespective of culture period. These results suggest that, at physiological concentrations, RA suppresses the differentiation of osteoprogenitor cells and regulates osteoblastic functions.
H Ishida, Department of Periodontology and Endodontology. Tokushima University School of Dentistry, 3-18-15 Kuramoto-cho, Tokushima 770, Japan
Regulation of rat placental lactogen (rPL)-II secretion: cAMP inhibits rPL-II secretion in vitro
Authors: Yamaguchi Masaaki , Kawai Motoyuki , Kishi Kurajiro , Miyake Akira 
Published: December 2008

Yamaguchi M, Kawai M, Kishi K, Miyake A, Regulation of rat placental lactogen (rPL)-II secretion: cAMP inhibits rPL-II secretion in vitro. Eur J Endocrinol 1995;133:342–6. ISSN 0804–4643
We examined whether epidermal growth factor (EGF), interleukin (IL)-1, IL-6 and cAMP analogs, which regulate mouse placental lactogen II secretion, affect rat placental lactogen (rPL)-II secretion using a rat choriocarcinoma cell line, Rcho-1. EGF, IL-1 and IL-6 did not affect rPL-II secretion, but 8-bromo-cAMP and forskolin inhibited rPL-II secretion by the 8th day of culture. The effects were dose dependent and the lowest concentrations of 8-bromo-cAMP and forskolin that significantly inhibited rPL-II secretion were 125 and 5 μmol/l, respectively. Cholera toxin also inhibited rPL-II secretion. The reverse hemolytic plaque assay for rPL-II indicated that the cells releasing rPL-II in the culture were giant cells and that 8-bromo-cAMP decreased the number of rPL-II-releasing cells. Western blot analysis of rPL-II yielded a single band at approximately 24.5 K, and 8-bromo-cAMP treatment significantly reduced the band intensity. Northern blot analysis of rPL-II indicated that 8-bromo-cAMP also reduced rPL-II gene expression. These findings suggest that the increase of intracellular cAMP accumulation results in inhibition of rPL-II secretion by decreasing rPL-II gene expression and inhibiting giant cell differentiation.
Masaaki Yamaguchi, Department of Obstetrics and Gynecology, Osaka University Medical School, 2-2 Yamadaoka, Suita, Osaka 565, Japan
Pups removal enhances thyrotropin-releasing hormone mRNA in the hypothalamic paraventricular nucleus
Authors: Uribe Rosa Maria , Joseph-Bravo Patricia , Charli Jean-Louis 
Published: December 2008

Uribe RM, Joseph-Bravo P, Charli J-L. Pups removal enhances thyrotropin-releasing hormone mRNA in the hypothalamic paraventricular nucleus. Eur J Endocrinol 1–60. ISSN 0804–4643
Previous studies have shown that lactation and suckling alter thyrotropin-releasing hormone (TRH) biosynthesis in hypothalamic paraventricular neurons. The amounts of paraventricular TRH mRNA and mediobasal hypothalamus (MBH) TRH were determined following removal of the pups to examine whether paraventricular TRH neuron activity is altered during the transition from lactation to estrous cycle. Paraventricular TRH mRNA and MBH TRH levels were determined by Northern blot analysis and radioimmunoassay, respectively. We had shown previously that after an 8-h withdrawal of the pups at mid-lactation the MBH TRH and paraventricular TRH mRNA levels are not modified. This condition was compared to one where pups were removed for 56 h, finding a significant decrease (46%, p < 0.005) of MBH TRH and a significant increase (156%, p < 0.02) of paraventricular TRH mRNA. The effect observed in the paraventricular TRH mRNA was correlated negatively with the serum corticosterone levels, a potential negative regulator of paraventricular TRH mRNA. The results were similar if a 1-h suckling period was introduced 8 h after withdrawal of the pups to induce a transient increase of corticosterone levels. The pattern of TRH mRNA was specific to the paraventricular nucleus because there was no enhancement in the preoptic area-anterior hypothalamus. In summary, our data suggest that TRH biosynthesis in paraventricular neurons is slowly adjusted after withdrawal of the pups, possibly to prepare TRH neurons to the new secretory demands of the estrous cycle.
JL Charli, Instituto de Biotecnologia, UNAM, AP 510-3, Cuernavaca, Mor. 62271, México
Bone mineral metabolism in girls with precocious puberty during gonadotrophin-releasing hormone agonist treatment
Authors: Antoniazzi Franco , Bertoldo Francesco , Zamboni Giorgio , Valentini Roberta , Sirpresi Stefania , Cavallo Luciano , Adami Silvano , Tato Luciano 
Published: December 2008

Antoniazzi F, Bertoldo F, Zamboni G, Valentini R, Sirpresi S, Cavallo L, Adami S, Tatò L. Bone mineral metabolism in girls with precocious puberty during gonadotrophin-releasing hormone agonist treatment. Eur J Endocrinol 1995;133:412–7. ISSN 0804–4643
Bone mineral metabolism and mineralization before and during treatment were studied in 10 girls aged 6.9–8.4 years affected by central precocious puberty and treated with gonadotrophin-releasing hormone agonist (GnRHa) leuprolide acetate depot, in order to understand better the consequences of oestrogen deficiency and the reduction of growth hormone (GH)–insulin-like growth factor I (IGF-I) axis activity. Before and after 12 months of therapy, the patients underwent a clonidine stimulation test and a 4-day calcitriol osteoblast stimulation test. On day 0, day 5 and at 3-month intervals thereafter, serum calcium, phosphate, alkaline phosphatase, IGF-I, IGF binding protein 3 (IGFBP-3), GH, GH binding protein and osteocalcin levels were measured; urinary calcium, phosphate and hydroxyproline levels were evaluated in fasting spot samples. Trabecular and cortical bone mass variations, measured by dual X-ray absorptiometry in the lumbar spine and by dual photon absorptiometry in the radius, respectively were evaluated before the start and after 12 months of therapy. During treatment, a decrease of serum oestradiol levels from pubertal to prepubertal levels was observed. The GH peak following clonidine diminished significantly after 1 year. Growth hormone binding protein showed a slight increase, and IGF-I and IGFBP-3 decreased, although not significantly. Osteocalcin levels decreased significantly after 9 and 12 months of treatment, but they did not change significantly after calcitriol load, either before or after GnRHa therapy. Urinary hydroxyproline decreased significantly after 12 months. Before therapy, lumbar spine and radius bone mass were high for chronological age but appropriate for bone age; after 12 months of treatment, bone mass in the lumbar spine, but not in the radius, had decreased significantly. In our patients, regression of pubertal development was associated with a reduction of trabecular bone mass, which appears to be the primary consequence of GnRHa therapy and possibly related to decreased GH secretion.
Franco Antoniazzi, Clinica Pediatrica, Università di Verona, Policlinico Borgo Roma, 1-37134 Verona, Italy
Changes in systemic gonadal and adrenal steroids in asymptomatic human immunodeficiency virus-infected men: relationship with the CD4 cell counts
Authors: Laudat Antoine , Blum Laurent , Guéchot Jérôme , Picard Odile , Cabane Jean , Imbert Jean Claude , Giboudeau Jacqueline 
Published: December 2008

Laudat A, Blum L, Guechot J, Picard O, Cabane J, Imbert JC, Giboudeau J. Changes in systemic gonadal and adrenal steroids in asymptomatic human immunodeficiency virus-infected men: relationship with the CD4 cell counts. Eur J Endocrinol 1995;133:418–24. ISSN 0804–4643
Serum sex hormone-binding globulin (SHBG), testosterone, non-SHBG-bound testosterone, androstenedione, dihydrotestosterone (DHT), dehydroepiandrosterone (DHEA), follicle-stimulating hormone (FSH), luteinizing hormone (LH) and cortisol were measured in 58 homosexual men seropositive for human immunodeficiency virus (HIV), all clinically asymptomatic (Centers for Disease Control 1993 classification stage A). The HIV patients were divided into four groups according to the CD4 lymphocyte count—group 1 (more than 500/μl, N= 14), group 2 (between 350 and 500/μl, N= 16), group 3 (between 200 and 349/μl, N = 22) and group 4 (less than 200/μl, N = 6)—and compared with 11 antibody-negative men as controls. The SHBG levels were significantly increased in groups 1, 2, 3 (p < 0.01) and 4 (p < 0.05) compared with controls, with no differences between groups of patients. Compared with controls, testosterone concentrations were significantly lower in group 4 (p < 0.05) and non-SHBG-bound testosterone levels were significantly lower in groups l(p < 0.05), 2 (p < 0.01), 3 (p < 0.001) and group 4 (p < 0.001); DHT and androstenedione levels were significantly lower in group 4 (p < 0.05) and DHEA levels were significantly lower in group 2, group 3 (p < 0.01) and group 4 (p< 0.05) than in controls. Cortisol levels were significantly increased in groups 1 and 4 (p < 0.05) and FSH and LH concentrations were not significantly higher in HIV-infected men than in controls. Also, the DHEA, androstenedione, non-SHBG-bound testosterone and DHT levels were correlated with CD4 cell counts, showing that hypogonadism occurs as the CD4 lymphocytes decrease. A strong reverse correlation between CD4 cell counts and cortisol/DHEA ratios (p < 0.001) confirms the alterations in adrenal steroid secretion, with a shift from androgen to glucocorticoid production as the disease progresses. These data show that in asymptomatic HIV-infected patients serum SHBG levels increase independently of CD4 cells counts, even in patients with undiminished CD4 cell counts; an alteration in serum androgen occurs as the CD4 cell counts decrease; and the cortisol/DHEA ratios increase as the CD4 cell counts decrease, resulting from alterations in adrenal secretion with both a decrease in serum DHEA levels correlated with CD4 cell counts and a slight increase in cortisol levels.
Jérôme Guéchot, Laboratoire de Biochimie-Hormonologie, Hôpital Saint-Antoine, 184 rue du Faubourg, Saint-Antoine, 75571 Paris Cedex 12, France