bluuebunny/crossref_metadata_2025 huggingface dataset:
Follow-up study on the effects of thyroid hormone administration on androgen metabolism of peripubertal rat Sertoli cells
Authors: Panno ML , Salerno M , Lanzino M , De Luca G , Maggiolini M , Straface SV , Prati M , Palmero S , Bolla E , Fugassa E , Andò S
Published: December 2008

Panno ML, Salerno M, Lanzino M, De Luca G, Maggiolini M, Straface SV, Prati M, Palmero S, Bolla E, Fugassa E, Andò S. Follow-up study on the effects of thyroid hormone administration on androgen metabolism of peripubertal rat sertoli cells. Eur J Endocrinol 1995;132:236–41. ISSN 0804–4643

The inhibitory effect of triiodothyronine (T3) given in early postnatal life on Sertoli cell proliferative activity, leading to their precocious terminal differentiation, has been demonstrated previously. However, data concerning the role of thyroid hormone on androgen metabolism of Sertoli cells during the same period are still lacking. In this study we performed a time-course investigation on the effects of T3 treatment on testosterone metabolism in Sertoli cells isolated from 2-, 3- and 4-weeks-old euthyroid rats. Triiodothyronine (3 μg/100 g body wt) was given ip., during the last week prior to sacrifice. Sertoli cells from all animal groups initially were cultured under basal conditions during the first 24 h and subsequently in the presence of testosterone (0.5 μmol/l) with or without T3 (1 nmol/l) for an additional 24 h. This treatment given to 2-week-old animals resulted in reduced testicular growth. As far as androgen metabolism is concerned, T3 in vivo and in vitro treatment in 2- and 3-week-old animals induced a lowering of dihydrotestosterone ± 3α-diol with an enhancement of the two other 5α-reduced androgens. The effect was much less pronounced in the oldest group. In both 2-and 3-week-old treated rats a marked reduction of oestradiol was observed, which indicates an inhibition of aromatase activity, mainly in younger animals. This enzyme has been reported to be extremely active in Sertoli cells of rats (of the same strain) between the age of 5 and 20 days, but it decreases rapidly thereafter. The results suggest that T3 given in early postnatal life could modify directly the androgen metabolism in Sertoli cells.

Sebastiano Andò, Cattedra di Fisiopatologia Endocrina, Dipartimento di Biologia Cellulare, Università della Calabria, 87030 Arcavacata di Rende, Cosenza, Italy
Dexamethasone therapy is associated with a rise in urinary epidermal growth factor concentrations in the preterm infant
Authors: Scott Susan M , Rogers Cathy , Backstrom Conra
Published: December 2008

Scott SM, Rogers C, Backstrom C. Dexamethasone therapy is associated with a rise in urinary epidermal growth factor concentrations in the preterm infant. Eur J Endocrinol 1995;132:326–30. ISSN 0804–4643

The effect of glucocorticoid hormones on epidermal growth factor (EGF) concentrations has not been described in the premature infant. We examined this relationship in a group of infants treated with dexamethasone for airway edema (three to five doses) or chronic lung disease (six weeks of a tapering protocol). We collected urinary samples in 45 infants (25 for airway edema, 20 for chronic lung disease) before, during and after the use of dexamethasone. The EGF values were unchanged in infants that were given dexamethasone for airway edema. In contrast, all infants treated for chronic lung disease increased their EGF values by 1 week of therapy. At the end of the dexamethasone taper, ten of the infants had recovered successfully from ventilatory support. This group of infants had post-therapy EGF values that were significantly higher than pretherapy values. In the ten infants that were still ventilator dependent at the end of therapy, EGF values were not different from pretherapy values. We conclude that dexamethasone therapy was associated with an increase in urinary EGF values in the preterm infant treated for at least 1 week. The positive correlation of tapering from ventilatory support with increases in EGF values suggests that EGF may be a marker of dexamethasone effect or an effector of dexamethasone action.

Susan M Scott, University of New Mexico, School of Medicine, Department of Pediatrics, ACC 3-West, Albuquerque, NM 87131-5311, USA
Effect of streptozotocin injection on expression of immunoreactive foilistatin and βA and βB subunits of inhibin/activin in rat pancreatic islets
Authors: Ogawa Kenji , Ono Kenichiro , Kurohmaru Masamichi , Hayashi Yoshihiro
Published: December 2008

Ogawa K, Ono K, Kurohmaru M, Hayashi Y. Effect of streptozotocin injection on expression of immunoreactive follistatin and βA and βB subunits of inhibin/activin in rat pancreatic islets. Eur J Endocrinol 1995;132:363–9. ISSN 0804–4643

The effect of streptozotocin (STZ) on expression of immunoreactive follistatin and β-subunits of inhibin/activin in pancreatic islets was studied by immunohistochemistry. To localize immunoreactive follistatin in pancreatic islets, two different anti-follistatin sera were used. Anti-follistatin(300–315) serum detects only long-form follistatin, while anti-follistatin(123–134) serum detects both long- and C-terminal truncated short-form follistatin in sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblotting. Although an intense reaction with anti-follistatin(123–134) was found in pancreatic B cells, a reaction with anti-follistatin(300–315) was not present in any type of cells. This result suggests that only short-form follistatin is expressed in pancreatic islets. It was confirmed that immunoreaction with anti-βA(1–10)-Tyr serum was found in pancreatic B cells. The anti-βB(1–10)-Tyr reaction was intense in A cells but weak in B cells. These findings suggest that the expression pattern of each β-subunit differs in each type of islet cells. At 2 weeks after STZ injection (65 mg/kg), insulin immunoreaction still remained in B cells, although most pancreatic B cells were destroyed. In contrast, immunoreactions of follistatin and β-subunits in B cells disappeared 24 h after STZ treatment. These results indicate that STZ affects the production of follistatin or β-subunits of inhibin/activin in pancreatic B cells rather than insulin secretion.

Kenji Ogawa, Department of Veterinary Anatomy, Faculty of Agriculture, The University of Tokyo, Bunkyo-ku, Tokyo 113, Japan
Retrospective evaluation of subtotal and total thyroidectomy in Graves' disease with and without endocrine ophthalmopathy
Authors: Winsa Brita , Rastad Jonas , Åkerström Göran , Johansson Henry , Westermark Kerstin , Karlsson F Anders
Published: December 2008

Winsa B, Rastad J, Åkerström G, Johansson H, Westermark K, Karlsson FA. Retrospective evaluation of subtotal and total thyroidectomy in Graves' disease with and without endocrine ophthalmopathy. Eur J Endocrinol 1995;132:406–12. ISSN 0804–4643

A retrospective analysis was performed in 173 consecutive patients with Graves' disease (GD) with the principal aim of evaluating the influences of subtotal (N = 157) and total (N = 19) thyroidectomy on postoperative recurrence rates, endocrine ophthalmopathy (EO) and thyrotropin receptor antibody (TSH-R-ab) titres. Postoperatively recurrent disease, identified by increased thyroid hormone levels, occurred in 32 patients (20%) who underwent subtotal resection. These recurrences were associated with over-representation of preoperative EO (p < 0.001) as well as high TSH-R-ab levels post-operatively (p < 0.05–0.01). Subtotal and total resections were followed by an aggravation of preoperative EO in nine (16%) and one (6%), and by a development of EO in two and none of the patients, respectively. Persistently elevated TSH-R-ab titers during thyrostatic therapy became close to normalized in seven (32%) and 15 (88%) of the patients undergoing subtotal or total thyroidectomies, respectively, which illustrates a thyroid tissue dependency of the autoantibody production. Among the total material of 173 patients, altogether 75 cases exhibited persistent or progressive EO and/or TSH-R-ab elevation after more than 1 year of preoperative thyrostatic treatment. In this group, recurrent GD or aggravated EO occurred in 23 (39%) of those operated with subtotal resection and in one (6%) of those undergoing total thyroidectomy (p < 0.05). The results thus indicate that EO, particularly at the time of surgery, and prevailing TSH-R-ab titers are associated with an increased risk of recurrent GD and suggest that patients exhibiting these characteristics should benefit from total rather than subtotal thyroidectomy.

Brita Winsa, Department of Internal Medicine, University Hospital, S-751 85 Uppsala, Sweden
Kinetic analysis of thyroid hormone action on glucose metabolism in man
Authors: Müller MJ , Reynard CA , Burger AG , Toffolo G , Cobelli C , Ferrannini E
Published: December 2008

Müller MJ, Reynard CA, Burger AG, Toffolo G, Cobelli C, Ferrannini E. Kinetic analysis of thyroid hormone action on glucose metabolism in man. Eur J Endocrinol 1995;132:413–18. ISSN 0804–4643

Thyroid hormone action on insulin's effect on glucose kinetics was investigated with the use of a physiological three compartment model. In six healthy volunteers before and after 14 days of thyroxine treatment (300 μg/day), a bolus of [3-H3]glucose was injected and the time course of plasma radioactivity was followed closely for 150 min. Then a hyperinsulinemic (1 mU · min−1 · kg−1) and euglycemic clamp was started, and euglycemia was maintained for another 250 min. A second bolus of the tracer was then given at 240 min, and the plasma radioactivity was followed for 160 min. Insulin stimulated basal plasma glucose clearance fourfold (p < 0.001) and completely suppressed basal hepatic glucose production (p < 0.001). Concomitantly, the total distribution volume of glucose was increased by 19% (p < 0.05); this change was accompanied by about 50% expansion of the slowly exchanging glucose pool (putatively representing the insulin-dependent compartment). Thyroxine treatment increased plasma triiodothyronine by about 20% (0.1 > p > 0.05) but did not affect basal glucose turnover, insulin-stimulated plasma glucose clearance or the insulin-induced suppression of endogenous glucose output. However, thyroxine treatment blunted the insulin-induced increases in total distribution volume and the slowly exchanging pool of glucose (p = NS vs the basal state). We conclude that minor changes in plasma triiodothyronine (such as occur during overfeeding) do not interfere with the ability of insulin to stimulate the rate of disappearance of glucose or suppress endogenous glucose release; however, our data suggest that they induce finer changes in glucose kinetics, possibly reflecting acceleration or intracellular glucose degradation.

Manfred J Müller, Institut für Humanernährung und Lebensmittelkunde, Christian-Albrechts-Universität zu Kiel, Düsternbrooker Weg 17, D-24105 Kiel, Germany
Identification and quantification of human kidney atrial natriuretic peptide receptors
Authors: Kahana Luna , Yechiely Haya , Mecz Yoel , Lurie Aharon
Published: December 2008

Kahana L, Yechiely H, Mecz Y, Lurie A. Identification and quantification of human atrial natriuretic peptide receptors. Eur J Endocrinol 1995;132:465–71. ISSB 0804–4643

The present study determined 125I-label atrial natriuretic peptide (ANP) binding sites in human kidney glomerular and papillary membranes. The membranes were prepared from non-malignant renal tissue obtained at nephrectomy of patients with renal carcinoma. To evaluate the proportion of ANP receptor classes ANP-R1 (ANPR-A, -B) versus ANP-R2 (ANPR-C), competitive binding studies were performed using [125I]-ANP in the presence of increasing concentrations of ANP or an internally ring-deleted analog, des(Gln116, Ser117, Gly118, Leu119, Gly120)ANP(102–121), called C-ANP, which binds selectively to ANPR-C receptors. Analysis of the competitive binding curve with ANP in glomerular membranes suggested the presence of one group of high-affinity receptors with dissociation constant Kd = 26 ± 12 pmol/l and density Bmax = 101 ± 47 nmol/kg protein. A decrease of 10–30% in Bmax with no change in Kd was obtained in the presence of excess (10−6 mol/l) C-ANP, suggesting the existence of a small amount of a second class of receptors, the ANPR-C class. The densities of ANPR-A, -B versus ANPR-C receptors in human glomeruli, calculated from competitive inhibition experiments, were 75 ± 42 and 22 ± 16 nmol/kg protein (N = 8). Autoradiography of the sodium dodecyl sulfate polyacrylamide gel electrophoresis under reducing conditions showed two bands: a highly labeled 130kD band and a weakly labeled 66kD band, both displaced by ANP. Only the 66-kD band was displaced by the C-ANP analog. Human papilla membrane, as shown by competition binding studies and SDS gel electrophoresis, presented only one class of receptors with Kd = 40 ± 23 pmol/l (mean ± SD, N = 3) and Bmax = 17 ± 6.3 nmol/kg protein. No displacement of [125I]ANP with C-ANP analog could be detected. The Kd of the binding sites in human kidney papilla was not statistically different (p > 0.05) from the Kd values of the two receptor subtypes for ANP in glomeruli. Thus, human kidney, much like that of the rat, presents: two classes, the high- (ANPR-A, -B) and low (ANPR-C)-molecular-weight receptors, in glomerular membranes; only one class, the high-molecularweight receptors, in papillary membranes. In contrast to rat kidney, the high-molecular-weight ANPR-A, -B is the dominant class in human glomerular membranes.

Luna Kahana, Endocrine Laboratory, Carmel Medical Center, 7 Michal Street, Haifa 34362, Israel
Biphasic effect of interleukin-1β on arginine vasopressin-induced cellular cyclic adenosine monophosphate production in cultured rat renal papillary collecting tubule cells
Authors: Ishikawa San-e , Saito Toshikazu
Published: December 2008

Ishikawa S, Saito T. Biphasic effect of interleukin-1β on arginine vasopressin-induced cellular cyclic adenosine monophosphate production in cultured rat renal papillary collecting tubule cells. Eur J Endocrinol 1995;132:472–8. ISSN 0804–4643

The present study was undertaken to determine whether interleukin (IL)-1β affects the response of cellular cyclic adenosine monophosphate production to arginine vasopressin (AVP) in cultured rat renal papillary collecting tubule cells. Arginine vasopressin increased cellular cAMP production in a dose-dependent manner. A 10-min exposure of cells to IL-1β at a concentration of 1 × 10−12 mol/l or higher significantly reduced the AVP-induced increases in cellular cAMP production but did not affect the 2 × 10−8 mol/l forskolin-induced increases in cellular cAMP production. The IL-1β inhibition disappeared totally when cells were pretreated with 100 μg/1 pertussis toxin for 2 h. In contrast, more than a 30-min exposure of cells to IL-1β increased basal cAMP levels and enhanced both the AVP- and forskolin-induced increases in cellular cAMP production. These results indicate that IL-1β produces biphasic regulation of AVP-induced cellular cAMP production in renal papillary collecting tubule cells. The inhibition by IL-1β is dependent on the activation of pertussis toxin-sensitive G protein. However, the mechanism whereby the longer exposure to IL-1β enhances cAMP production remains to be determined.

San-e Ishikawa, Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical School, 3311-1 Yakushiji Minamikawachi-machi, Tochigi 329-04. Japan
Insulin-like growth factor I messenger ribonucleic acid expression in porcine thyroid follicles is regulated by thyrotropin and iodine
Authors: Hofbauer Lorenz C , Rafferzeder Michael , Janssen Onno E , Gärtner Roland
Published: December 2008

Hofbauer LC, Rafferzeder M, Janssen OE, Gartner R. Insulin-like growth factor I messenger ribonucleic acid expression in porcine thyroid follicles is regulated by thyrotropin and iodine. Eur J Endocrinol 1995;132:605–10. ISSN 0809–4643

Insulin-like growth factor I (IGF-I) has been shown to be released from thyrocytes in vitro. We investigated IGF-I mRNA expression during treatment with thyrotropin (TSH), forskolin and potassium iodide (KI) in intact porcine thyroid follicles ex vivo. Porcine thyroid follicles were prepared by collagenase digestion and cultured in the presence of TSH, forskolin or KI. After different incubation times, mRNA was isolated and examined by Northern hybridization with a porcine IGF-I cDNA probe of 405 bp in length. In untreated follicles no IGF-I mRNA was found, whereas in follicles stimulated with TSH an IGF-I mRNA of 7.0 kb was detected after 24 h, which persisted for another 24 h. Forskolin treatment mimicked the TSH effect, indicating that IGF-I mRNA expression may be stimulated by the adenylate cyclase pathway. Preincubation of the porcine follicles with KI decreased dose dependently the TSH-induced IGF-I mRNA expression, with complete inhibition at 10 μmol/l KI. These results suggest that TSH acts via the cAMP pathway to enhance IGF-I mRNA expression, which then may lead to an autocrine IGF-I stimulation. The IGF-I mRNA expression is under negative control of iodide.

Roland Gärtner, Medizinische Klinik, Ludwig Maximilians University, Ziemssenstrasse 1, 80336 München, Germany
Decreased serum testosterone and free triiodothyronine levels in healthy middle-aged men indicate an age effect at the pituitary level
Authors: Erfurth Eva Marie T , Hagmar Lars E
Published: December 2008

Erfurth EMT, Hagmar LE. Decreased serum testosterone and free triidothyronine levels in healthy middle-aged men indicate an age effect at the pituitary level. Eur J Endocrinol 1995;132:663–7. ISSN 0804–4643

In an attempt to study further the age-specific influence on the hypothalamo-pituitary–gonadal axis as well as the hypothalamo–pituitary–thyroid axis, we have now investigated young and middle-aged men, considering possible confounding factors. Both serum total testosterone, free testosterone and the total ratio of testosterone to sex-hormone binding globulin were significantly lower among middle-aged men as compared with young men (p = 0.02, p = 0.002 and p = 0.0003, respectively). In accordance with these findings there was also a decrease in the luteinizing hormone response to gonadotrophin-releasing hormone in the middle-aged men (p= 0.02). Free testosterone was correlated significantly with the luteinizing hormone response (r = 0.32, p = 0.02). Serum free triiodothyronine was significantly higher among young men as compared with middle-aged men (p = 0.002) and the thyrotrophin-releasing hormone-stimulated thyrotrophin response was also higher in the young group compared with the middle-aged group. The present results may indicate that the age effect on serum levels of testosterone and free triidothyronine is mediated at the pituitary level.

Eva Marie Erfurth, Dept. of Internal Medicine, University of Lund, S-221 85 Lund, Sweden
Serum levels of interleukin 6 and tumor necrosis factor-α in hyperthyroid patients before and after propylthiouracil treatment
Authors: Çelik Ismail , Akalin Sema , Erbaş Tomris
Published: December 2008

Çelik I, Akalin S, Erbaş T. Serum levels of interleukin 6 and tumor necrosis factor-α in hyperthyroid patients before and after propylthiouracil treatment. Eur J Endocrinol 1995;132:668–72. ISSN 0804–4643

Contrary to the usual inhibitory role of tumor necrosis factor-α (TNF-α) thyroid metabolism, it also has specific stimulatory effects in autoimmune thyroid disorders, including induction of HLA class II antigen-presenting cell—T cell interaction. Despite high intrathyroidal concentrations, various studies were not able to demonstrate high serum levels of TNF-α in patients with Graves' disease. To investigate this discrepancy we determined TNF-α and interleukin 6 (IL-6) levels in 25 hyperthyroid patients who responded to propylthiouracil treatment (16 with Graves' disease and nine with toxic multinodular goiter) and compared them with the levels found in euthyroid patients with simple diffuse goiter (n = 15) and normal healthy controls (n = 15). Median IL-6 levels were high in both Graves' disease and toxic multinodular goiter patients before propylthiouracil treatment (23 and 26.5 pg/ml, respectively). After restoring euthyroidism there was a statistically significant decline to near-normal levels (3 and 10 pg/ml, respectively). On the other hand, median serum TNF-α levels were high only in Graves' disease patients (20 pg/ml) and could not be normalized with antithyroid medication (20 pg/ml) compared to that of controls (5 pg/ml). Tumor necrosis factor-α, but not IL-6, was found to be high in the sera of Graves' disease patients when euthyroid, which may be due to an ongoing antigen–antibody interaction, a feature of autoimmune attack. It remains to be determined whether the degree of TNF-α and/or IL-6 elevation will be a predictor of disease recurrence.

Ismail Çelik, Section of Oncology, Dept. of Medicine, Hacettepe University Institute of Oncology, Ankara 06100, Turkey
Treatment of central precocious puberty with depot leuprorelin
Authors: Carel Jean-Claude , Lahlou Najiba , Guazzarotti Laura , Joubert-Collin Maryse , Roger Marc , Colle Michel , _ _ , Chaussain Jean Louis
Published: December 2008

Carel J-C, Lahlou N, Guazzarotti L, Joubert-Collin M, Roger M. Colle M, The French Leuprorelin Trial Group, Chaussain JL. Treatment of central precocious puberty with depot leuprorelin. Eur J Endocrinol 1995;132:699–704. ISSN 0804–4643

We evaluated the pituitary and gonadal suppression in 40 girls and nine boys treated with depot leuprorelin (3.75 mg sc if body weight ≥20kg, 1.87 mg if body weight <20 kg) every 28 days for central precocious puberty. Gonadal suppression was obtained in most of the children with this dose: 3 months after initiation of the treatment, 85% of children had a peak plasma luteinizing hormone response to gonadotropin-releasing hormone <3 IU/l and the gonadal axis remained suppressed throughout the duration of the study (up to 24 months). Four patients required higher doses of leuprorelin to achieve suppression. In two girls, a cutaneous reaction to the drug was associated with incomplete suppression and the treatment had to be interrupted. Plasma leuprorelin levels tended to increase from day 3 to day 28 after injection. Residual leuprorelin levels measured 28 days after injection were stable during the first year of the study. We conclude that an initial dose of depot leuprorelin of 3.75 mg sc every 28 days is efficient in most children with central precocious puberty.

Jean-Claude Carel, INSERM U342, Hôpital Saint Vincent de Paul, 82 av Denfert Rochereau, 75014 Paris, France
Growth hormone treatment during pregnancy in a growth hormone-deficient woman
Authors: Müller Jørn , Starup Jørgen , Christiansen J Sandahl , Jøgensen Jens OL , Juul Anders , Skakkebaek Niels E
Published: December 2008

Müller J, Starup J, Christiansen JS, Jørgensen JOL, Juul A, Skakkebaek NE, Growth hormone treatment during pregnancy in a growth hormone-deficient woman. Eur J Endocrinol 1995;132:727–9. ISSN 0804–4643

Information on the course and outcome of pregnancies in growth hormone (GH)-deficient patients is sparse, and GH treatment during pregnancy in such women has not been described previously. We have studied fetal growth and serum levels of GH, insulin-like growth factor I (IGF-I) and IGF binding protein 3 (IGFBP-3) during pregnancy, as well as birth weight and hormone levels after delivery in a 2 5-year-old woman with idiopathic, isolated GH deficiency diagnosed at the age of 7 years. As part of a clinical trial, the patient was treated with 2 IU/M2 GH for a period of 5 years. At this time she became pregnant after donor insemination. The GH treatment was continued until variant GH production from the placenta was evident. Serum levels of GH, IGF-I and IGFBP-3 were measured monthly during pregnancy after 3 days off GH therapy. Abdominal ultrasound was performed five times. Hormonal levels were measured immediately after delivery and during the following days. Serum GH and IGF-I levels increased during the second half of pregnancy: serum IGFBP-3 remained constant throughout pregnancy at a normal level. Serum levels of GH fell within 1 h after delivery, and levels of IGF-I and IGFBP-3 decreased into the range of GH-deficient women 4 days after. The fetal biparietal diameter increased normally, and birthweight was 3.564kg, length 52 cm. No adverse events were recorded. We conclude that the role of GH replacement during pregnancy of GH-deficient women should be investigated further.

Jørn Müller, Department of Growth and Reproduction, GR 5064, Rigshospitalet, 9 Blegdamsvej, DK-2100 Copenhagen ø, Denmark
Long-lasting effects of Triac and thyroxine on the control of thyrotropin and hepatic deiodinase type I
Authors: Juge-Aubry Cristiana E , Morin Odette , Pernin Agnés T , Liang Hong , Philippe Jacques , Burger Albert G
Published: December 2008

Juge-Aubry CE, Morin 0, Pernin AT, Liang H, Phillipe J, Burger AG. Long-lasting effects of Triac and thyroxine on the control of thyrotropin and hepatic deiodinase type I. Eur J Endocrinol 1995;132:751–8.

The purpose of this study was to investigate the relation between the serum levels of thyroid hormones and their biological effects. For this purpose, hypothyroid rats were studied after stopping treatment with a long-acting thyroid hormone, thyroxine (T4) and a short-acting one, triiodothyroacetic acid (Triac). Based on preliminary experiments with different doses of T4 and Triac, hypothyroid rats (N= 84) received over 6 days' injections of lOnmol Triac or 2 nmol T4/100 g body wt per day. Biological effects of Triac and T4 were measured in the pituitary, liver and kidney up to 8 days after stopping treatment. With Triac, serum thyrotropin (TSH) levels were inhibited completely 6 h after injection, yet after 24 h they were 4.9 ± 1.8 μ/l (hypothyroid 14.5 ± 0.8 μg/l). The rapid changes in serum TSH levels were followed by a more gradual increase in serum TSH levels were followed by a more gradual increase in serum TSH, which was similar to that after T4 injection. Even 8 days after Triac treatment, serum TSH levels did not reach the hypothyroid control levels. Changes in β-TSH mRNA levels also showed a prolonged inhibition after both treatments and a slow return to hypothyroid values, which was not complete 8 days after stopping treatment. A second parameter was hepatic 5′-deiodinase type I (5′D-I), The 6-day treatment with Triac had a markedly stronger effect on 5′D-I enzyme activity and mRNA levels than treatment with T4. Again, the effect disappeared slowly because hepatic activity was still above control levels 8 days after treatment. The mRNA levels of spot 14 also were higher with Triac. However, 4 days after stopping treatment with both hormones, mRNA levels had returned to hypothyroid values. These data suggest that at the pituitary level one can distinguish between rapid and slower effects. For 5′D-I activity, however, the effects are longlasting and there is no apparent difference in the duration of the effects between Triac or T4. They last much longer than the injected hormone. Our results show that even for parameters closely controlled by thyroid hormones, the expression and duration of thyroid hormone effects vary markedly, not only from organ to organ TSH/5′D-I but also within the same organ, depending on the parameters (5′D-I/ spot 14).

Cristiana E Juge-Aubry, Thyroid Unit, Hôpital Cantonal Universitaire, 1211 Geneva 14, Switzerland
Follicle-stimulating hormone–testosterone interaction in modulating steroidogenesis in bovine granulosa cells. I. Effect on progesterone production
Authors: Grasselli Francesca , Basini Giuseppina , Bussolati Simona , Tamanini Carlo
Published: December 2008

Grasselli F, Basini G, Bussolati S, Tamanini C. Follicle-stimulating hormone–testosterone interaction in modulating steroidogenesis in bovine granulosa cells. I. Effect on progesterone production. Eur J Endocrinol 1995;132:759–64. ISSN 0804–4643

The aim of this study was to investigate the effects of testosterone on basal and follicle-stimulating hormone (FSH)-induced progesterone production by cultured bovine granulosa cells. Granulosa cells were isolated from small (< 5 mm) and large (>8 mm) follicles and cultured for 48 h in 1 ml of Medium-199 with different concentrations of FSH (0.1, 1, 10 and 35 mg/l). In addition, the combined effects of different amounts of testosterone (1 nmol–10 μmol) and 1 mg/l FSH for 48 h on progesterone production by granulosa cells of both groups of follicles were studied; progesterone production during the subsequent 24-h incubation period was evaluated in the absence of hormones. In a third experiment, granulosa cells were treated with 500 μg of dibutyryl-cAMP and 10 μmol of testosterone for 48 h. At the end of each incubation period, the progesterone content in the culture media was determined by a validated radioimmunoassay. Basal progesterone release during the 48-h incubation period was higher in granulosa cells from small as compared to cells from large follicles; in both groups of cells, progesterone production was stimulated maximally by 1 mg/l FSH. The treatment with 10 μmol of testosterone induced a decrease of progesterone production in both groups of cells, while lower amounts exerted an inhibitory effect only in cells from large follicles. Furthermore, 10 μmol of testosterone inhibited FSH-induced progesterone release, while lower dosages were ineffective. Dibutyryl-cAMP stimulated significantly the progesterone output by granulosa cells of both groups and testosterone was effective in suppressing this increase. Our data demonstrate that testosterone plays an important role in regulating progesterone production by granulosa cells in that it inhibits (at high dosages) both basal and FSH-induced progesterone output. These data also suggest that the site of inhibition is distal to cAMP formation.

Carlo Tamanini, Istituto di Fisiologia Veterinaria. Via del Taglio 8, 43100 Parma, Italy
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