bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of epitestosterone on gonadotrophin synthesis and secretion
Authors: Lapcik O , Perheentupa A , Bicikova M , Huhtaniemi I , Hampl R , Starka L 
Published: December 2008

Abstract
The effects of 3-week treatment with increasing doses of epitestosterone (ET) on gonadotrophin gene expression and secretion, on testosterone and 5α-dihydrotestosterone (DHT) levels, and on the weight of testes and prostates, were studied in intact adult male rats. The hormones were delivered by means of silastic capsules of different lengths filled with the steroid. One group of rats received testosterone (T) instead of ET, to compare the results with previous studies concerning the testosterone effect. The controls were given capsules with glucose only. Treatment with ET, as well as with T, significantly reduced the weights of prostates. When the data from ET-treated rats and controls were combined, a significant negative correlation (P<0·001) was found between the weight of prostates and serum ET. T, in contrast to ET, also decreased significantly the weights of testes. ET treatment caused a significant reduction of serum T levels but only an insignificant decline of DHT levels, independent of the dose. Serum and pituitary (p) luteinizing hormone (LH) levels in the ET-treated rats did not change. Pituitary mRNA contents for the βLH subunit (βLH-mRNA) showed a dose-dependent significant increase, up to 170% (P<0·01), with ET treatment. pFSH decreased with the lowest ET (2 cm) dose (P<0·05), but no change was observed with the other doses. The mRNA for the common α-subunit also increased with the ET load. In conclusion, ET acts at several sites in the regulation of gonadotrophin formation and release. It enhances the steady-state mRNA levels of both gonadotrophins in the pituitary. At the same time, ET may act directly in the pituitary by inhibition of post-transcriptional events in LH synthesis. A direct inhibitory effect of ET at the hypothalamic level is also possible. The circulating levels of both gonadotrophins are thus the result of these composite effects.
Journal of Endocrinology (1994) 143, 353–358
Influence of tumour necrosis factor-α, tumour necrosis factor-β and interferon-γ, separately and added together with interleukin-1 β, on the function of cultured human thyroid cells
Authors: Rasmussen Å K , Kayser L , Feldt-Rasmussen U , Bendtzen K 
Published: December 2008

Abstract
Interleukin (IL)-1, tumour necrosis factor (TNF)-α and interferon (IFN)-γ have been demonstrated in thyroid tissue. We have previously shown that high concentrations of IL-1 inhibit and low concentrations stimulate human thyroid cell function in vitro. In the present study, TNF-α, TNF-β and IFN-γ all inhibited thyroglobulin (Tg) and cAMP production from cultured human thyroid cells. When TNF-α was added simultaneously with IL-1 β, the highest concentration of TNF-α (106 U/l) enhanced the inhibition of Tg and cAMP induced by IL-1β (1–105 U/1). TNF-β had no influence on IL-1β-induced inhibition. IFN-γ (104 U/1) added together with IL-1β in lower concentrations (1—102 U/l) stimulated cAMP production, while at high concentrations of IL-1β (105 U/1), IFN-γ enhanced the inhibitory influence of IL-1 β on Tg production.
The hormones of the immune system, IL-1, TNF and IFN-γ, may thus contribute to the decreased thyroid function characteristic of some thyroid inflammatory diseases.
Journal of Endocrinology (1994) 143, 359–365
Differential response of neuropeptide Y, substance P and vasoactive intestinal polypeptide in the rat anterior pituitary gland to alterations in thyroid hormone status
Authors: Jones P M , Ghatei M A , Wallis S C , Bloom S R 
Published: December 2008

Abstract
We have compared the effects of thyroidectomy with those of thyroxine (T4) replacement and excess T4 treatment on neuropeptide Y (NPY) in the rat anterior pituitary, and compared these with the effects on substance P (SP) and vasoactive intestinal peptide (VIP). Thyroidectomy produced large increases in the peptide content of NPY (335 ± 58 fmol/gland vs 15 ± 4 fmol/gland in controls), SP (581 ±90 vs 199 ±32 fmol/gland) and VIP (1386 ± 395 vs 417 ± 77 fmol/gland) together with large increases in the respective prohormone encoding mRNAs, NPY 21 760%±1290%, preprotachykinin-A (PPT-A; which encodes the substance P precursor) 1744%± 190% and VIP 680% ± 129%. Thyroidectomy together with T4 replacement produced an increase in both NPY peptide (426 ±72 vs 15 ±4 fmol/gland) and mRNA content 970%±156% of controls). The peptide contents of SP and VIP were not significantly different from controls. PPT-A and VIP mRNA levels were decreased relative to controls (31%±8% and 23%± 10% respectively). In intact animals treated with excess T4 (hyperthyroid animals), SP and VIP peptide contents were significantly reduced (55 ±13 vs 199±32 fmol/gland and 226 ± 24 vs 417± fmol/gland respectively) and the SP and VIP encoding mRNAs were also decreased (8% ±3% and 11%±4% respectively). In this group there was no detectable alteration in either the peptide or mRNA content of NPY. Thus, the response of pituitary NPY to thyroid hormone manipulations cannot be explained in terms of negative feedback physiology and is different from those of SP and VIP. The results suggest that the regulation of locally produced NPY in the rat anterior pituitary is complex and may be influenced by thyroidal factors in addition to T4.
Journal of Endocrinology (1994) 143, 393–397
High plasma insulin-like growth factor-II and low lipid content in transgenic mice: measurements of lipid metabolism
Authors: Da Costa T H M , Williamson D H , Ward A , Bates P , Fisher R , Richardson L , Hill D J , Robinson I C A F , Graham C F 
Published: December 2008

Abstract
Transgenic mice were made by introducing extra copies of the mouse insulin-like growth factor-II (IGF-II) gene driven by the bovine keratin 10 promoter (BKVI). The adult plasma IGF-II levels were elevated at least three times in one line. In this line, there was a lower lipid content of both brown and white adipose depots at 2–4 months of age, and 40% less fat in the carcass at 7–9 months. The low lipid phenotype was not detected in the carcass at 2 weeks after birth. The lean characteristic was attributed to circulating IGF-II because the transgene was not expressed in fat. At 2–4 months of age, the transgenes oxidized more oral lipid, and less of this lipid was incorporated into the whole body and the epididymal fat. In contrast, the interscapular brown adipose tissue maintained lipid incorporation and lipoprotein lipase activity despite its reduced size. The altered activity of the brown adipose tissue may account for the gradual onset and persistence of the lean feature of the transgenic mice. There were no substantial changes in lipogenesis which could account for the low fat content. The plasma levels of IGF-I, insulin, glycerol, non-esterified fatty acids, triacylglycerols and glucose were not greatly changed and the pituitary GH content was within the normal range.
Journal of Endocrinology (1994) 143, 433–439
Pituitary-specific transcription factor Pit-1 in the rdw rat with growth hormone- and prolactin-deficient dwarfism
Authors: Ono M , Harigai T , Furudate S 
Published: December 2008

Abstract
The pituitary gland of the rdw rat (gene symbol: rdw) with hereditary dwarfism expresses 30–100 times less GH and prolactin (PRL) mRNA than normal controls. To clarify the features of rdw rats, TSH and the pituitary-specific transcription factor Pit-1, which is involved not only in the gene expression of GH and PRL but in somatotroph, lactotroph and thyrotroph development as well, were examined. The rdw pituitary contained about seven times more TSHβ mRNA than the normal control, whereas Pit-1 mRNA expression in rdw and control was the same. Nucleotide sequencing of PCR-amplified Pit-1 cDNA indicated that the deduced amino acid sequence of rdw Pit-1 was identical with that of the normal rat. Using an antibody against rat Pit-1 protein produced in E. coli, Western blotting analysis demonstrated the presence of the same amount of Pit-1 protein in rdw and normal rat pituitaries. The distribution of Pit-1-positive cells in the anterior pituitary was essentially the same in rdw and normal rats. It follows from these findings that the defective gene in the rdw rat is unrelated to the Pit-1 gene and the normal quantity of Pit-1 protein is insufficient to produce normal amounts of GH and PRL in the rdw pituitary. These and previous results suggest that the reduction in GH and PRL production in the rdw pituitary might be due to that in thyroid hormone production.
Journal of Endocrinology (1994) 143, 479–487
ANF(1-28) is a Potent Suppressor of Pro-opiomelanocortin (POMC) mRNA but a Weak Inhibitor of βEP-LI Release from AtT-20 Cells
Authors: Tan Tean T , Yang Zhiyu , Huang Weiqing , Lim Alan T. 
Published: December 2008

ABSTRACT
Controversies remain whether atrial natriuretic factor (ANF) may play a role in modulating the release of POMC derived peptides from pituitary corticotrophs. Employing AtT-20 mouse pituitary tumour cells, we report here the effects of rat ANF(1–28) and sodium nitroprusside (SNP), both of which augment cellular levels of cGMP through activating particulate and soluble guanylyl cyclases respectively, on the expression of POMC mRNA abundance. Furthermore, the cellular contents and secretion of (beta endorphin-like immunoreactivity) βEP-LI from these cultures were also examined. Whereas the abundance of POMC mRNA was found to be markedly suppressed following 4h of incubation with rANP(1–28) (0.01 to 1 μM), SNP (0.1 to 10 μM) and dibutyryl-cGMP (1 to 100 μM) in a dose related manner, only a modest reduction in the release and cell contents of βEP-LI was found in some of these cultures. It is also of interest to note that in all the cases examined, the inhibitory effect was associated with a significant suppression of cAMP levels in the cultures. Taken together, our present findings suggest that ANF may play a more important role in suppressing the production than the release of POMC related peptides from AtT-20 cells. Thus, it raises the possibility that hypothalamic ANF may likewise modulate the function of the pituitary-adrenal axis through exerting a greater effect on inhibiting the production than the secretion of pituitary ACTH.
Influence of progesterone on boar sperm capacitation
Authors: Barboni B , Mattioli M , Seren E 
Published: December 2008

Abstract
This research investigates the effect of progesterone (P4) on boar sperm capacitation. Ejaculated spermatozoa were washed and incubated under capacitating conditions with or without P4. At different times of incubation samples of sperm were exposed to solubilized zonae pellucidae (ZP) and the degree of capacitation was evaluated by the incidence of zona-induced acrosome reaction (AR). The status of the acrosome was studied by using an FITCconjugated lectin (Pisum sativum agglutinin; FITC-PSA). The effect of P4 on the fertilizing ability of semen was then evaluated in an in vitro fertilization system by exposing in vitro matured oocytes to sperm preincubated for 2 or 4 h with or without P4, under capacitating conditions. PSA staining showed that P4 does not affect the incidence of spontaneous AR. By contrast, spermatozoa incubated with P4 showed a higher percentage of AR than controls after the exposure to solubilized ZP. This enhanced reactivity to ZP suggests a direct effect of P4 on sperm capacitation. The in vitro fertilization assay was consistent with these results demonstrating a higher fertilizing ability in sperm preincubated with P4 than in controls while the steroid was without effect when added only during the fertilization step. These results demonstrate that P4 improves the fertilizing ability of boar semen essentially by facilitating the process of capacitation.
Journal of Endocrinology (1995) 144, 13–18
Measurements of chromogranin A, chromogranin B (secretogranin I), chromogranin C (secretogranin II) and pancreastatin in plasma and urine from patients with carcinoid tumours and endocrine pancreatic tumours
Authors: Stridsberg M , Öberg K , Li Q , Engström U , Lundqvist G 
Published: December 2008

Abstract
Chromogranins and/or secretogranins constitute a family of water-soluble acidic glycoproteins that are present in almost all endocrine, neuroendocrine and neuronal tissue. Antibodies against chromogranins have been widely used for immunohistochemical staining of endocrine tissue and tumours of neuroendocrine origin. Furthermore, measurements of circulating chromogranin A have been used as a reliable marker for neuroendocrine tumour growth. In this study, we describe the development of specific antibodies against chromogranin A, chromogranin B (secretogranin I), chromogranin C (secretogranin II) and pancreastatin. The antibodies were used for immunohistochemical staining of normal and neoplastic neuroendocrine tissue and development of reliable radioimmunoassays for chromogranin A, chromogranin B, chromogranin C and pancreastatin. In 44 patients with carcinoid tumours, 17 patients with sporadic endocrine pancreatic tumours and 11 patients with endocrine pancreatic tumours and the multiple endocrine neoplasia 1 syndrome, plasma measurements revealed elevated chromogranin A levels in 99%, elevated chromogranin B in 88%, elevated chromogranin C in 6% and elevated pancreastatin in 46% of the patients. Urinary measurements revealed elevated levels in 39%, 15%, 14% and 33% of the patients respectively. Gel permeation chromatography of plasma and urine showed that circulating chromogranin A, and immunoreactive fragments of chromogranin A, had a higher molecular weight distribution than the chromogranin A fragments excreted to the urine. Furthermore, it was noted that most of the patients excreting chromogranin A fragments to the urine had previously been treated with streptozotocin, a cytotoxic agent known to induce renal tubular dysfunction. The antibodies raised proved useful for immunohistochemical staining and visualised endocrine cells in pancreatic islets, adrenal medulla and the small intestine as well as in endocrine pancreatic tumours, pheochromocytoma and midgut carcinoid tumours. In conclusion, the antibodies raised were useful for both immunohistochemical staining of normal tissue and endocrine tumours as well as development of specific radioimmunoassays for plasma measurements of the different chromogranins. Furthermore, we show that plasma measurements of chromogranin A and B were superior to measurements of chromogranin C and pancreastatin and plasma measurements of the different chromogranins were more reliable as markers for tumour growth than the corresponding urine measurements.
Journal of Endocrinology (1995) 144, 49–59
A homologous radioimmunoassay for ovine insulin-like growth factor-binding protein-2: ontogenesis and the response to growth hormone, placental lactogen and insulin-like growth factor-I treatment in sheep
Authors: Gallaher B W , Breier B H , Blum W F , McCutcheon S N , Gluckman P D 
Published: December 2008

Abstract
Although insulin-like growth factor-binding protein-2 (IGFBP-2) is an abundant IGFBP in fetal and postnatal plasma, its regulation is not yet clearly understood. To address this question in sheep, we purified ovine IGFBP-2 and developed a homologous radioimmunoassay. We have studied its ontogenesis and measured serum concentrations of ovine IGFBP-2 after bovine growth hormone (bGH), ovine placental lactogen (oPL) and IGF-I treatment.
Concentrations of IGFBP-2 were high at 125 days of gestation (550 ± 15 μg/l) but fell after birth P<0·05) and plateaued after 1 year of age (340 ± 20 μg/l). In lactating ewes, bGH treatment for 7 days significantly reduced (21%; P<0·05) IGFBP-2 relative to the saline-treated group. Similarly, in neonatal lambs, bGH treatment from day 3 to day 23 of life reduced (P<0·05) IGFBP-2 by 23% relative to the saline-treated group. oPL had no effect on serum levels of IGFBP-2 in the ewe or the neonatal lamb. In well-fed yearling lambs, treatment with IGF-I reduced IGFBP-2 values by 27% (P<0·05) relative to control animals. In yearling lambs, reduced nutrition increased plasma IGFBP-2 (41%; P<0·05). However this increase was abolished by IGF-I treatment.
The changes in plasma levels of IGFBP-2 were positively related to changes in IGF-II while there was a negative relationship between circulating IGF-I and IGFBP-2 such that both IGF-I and IGF-II may play a role in the regulation of IGFBP-2 in serum.
Journal of Endocrinology (1995) 144, 75–82
Changes induced by non-enzymatic glycosylation of IGF-binding protein-3: effects on its binding properties and on its modulatory effect on IGF-I mitogenic action
Authors: Cortizo A M , Gagliardino J J 
Published: December 2008

Abstract
The aim of this study was to demonstrate the feasibility of in vitro non-enzymatic glycosylation of IGF-binding protein-3 (IGFBP-3) and whether this process affects its binding properties and its modulatory effect on IGF-I mitogenic activity. Swiss 3T3 fibroblasts were cultured and the IGFBP-3 released into the medium (CM) glycated with either labelled or unlabelled glucose. Parallel glycation studies were performed using standard human IGFBP-3. Both species of IGFBP-3 became effectively glycated in a dose-dependent manner. Glycated IGFBP-3 bound larger amounts of 125I-labelled IGF-I than its non-glycated form. According to Scatchard analysis this effect might be due to an increase in the number of binding sites of the IGFBP-3 molecule rather than to changes in its affinity constants, which remain unchanged. Preincubation of fibroblasts with CM containing IGFBP-3 for 16 h before the addition of IGF-I enhanced the stimulatory effect of the hormone on thymidine incorporation into cell DNA. This potentiation was blunted when in vitro glycated instead of non-glycated IGFBP-3 was employed. These results provide further evidence of the in vitro glycation of IGFBP-3 and demonstrate that this process affects both its binding properties and its enhancing effect on IGF-I mitogenic activity. These changes may explain, at least partially, the development of many alterations observed in poorly controlled diabetic patients.
Journal of Endocrinology (1995) 144, 119–126
ETA and ETB endothelin receptors in human myometrium characterized by the subtype selective ligands BQ123, BQ3020, FR139317 and PD151242
Authors: Bacon C R , Morrison J J , O'Reilly G , Cameron I T , Davenport A P 
Published: December 2008

Abstract
ETA selective (BQ123, FR139317, PD151242) and ETB selective (BQ3020) ligands were used to define the binding characteristics and contractile function of endothelin receptor subtypes in human myometrium. In saturation binding assays with 10 μm-thick tissue sections [125I]endothelin-1 (ET-1) bound with a single affinity to receptors in the myometrium (Kd, 1·19±0·17 nm) and adjacent endometrium (Kd, 1·39±0·51 nm). Competition binding assays in myometrium revealed a heterogeneous population of receptors with BQ123 (Kd ETA, 1·43±0·33 nm; Kd ETB, 39·91±9·06 μm), FR139317 (Kd ETA, 2·54±0·87 nm; Kd ETB, 89·79±24·34 μm) and BQ3020 (Kd ETA, 4·57±0·58 μm; Kd ETB, 90·07±19·53 nm). The presence of these receptors in myometrium was confirmed by saturation assays with the new ETA selective ligand [125I]PD151242 (Kd, 0·93±0·08 nm Bmax 138·7±1·0 fmol/mg protein) and the ETB selective [125I]BQ3020 (Kd, 0·62±0·07; Bmax 44·5±1·1 fmol/mg protein). Reverse-transcriptase PCR assays detected mRNA encoding both receptor subtypes in myometrium.
Autoradiography with radiolabelled PD151242 and BQ3020 demonstrated that ETA receptors were the predominant subtype in the myometrium and identified a population of ETB receptors in the endometrium.
In tissue bath experiments, an ET-1-induced increase in contractility of myometrial strips was antagonized by 10 μm FR139317 but not by BQ123 at the same concentration. The ETB agonist BQ3020, which is a potent agonist in animal tissue, did not increase contractility when tested at concentrations up to 2 μm.
The results of this study suggest that ETA endothelin receptors and a smaller population of ETB receptors are found in human myometrium. ETA, but not ETB, receptors mediate myometrial contractility. The function of ETB receptors in human uterus remains to be elucidated.
Journal of Endocrinology (1995) 144, 127–134
Evidence for chromium acting as an essential trace element in insulin-dependent glucose uptake in cultured mouse myotubes
Authors: Morris B , Gray T , MacNeil S 
Published: December 2008

Abstract
Previous work from this and other laboratories has suggested that the trace element chromium plays some role in glucose homeostasis. In this study, we sought to characterise an in vitro cell culture model in which the effects of chromium on insulin-dependent glucose uptake could be studied. Mouse C2C12 myoblasts were differentiated to form myotubes in culture in chromium-replete or chromium-poor media. Chromium levels in standard media were 0·56±0·01 μg/l (mean ± s.e.m.) compared with 0·09±0·01 μg/l in chromium-poor media.
In chromium-poor media, insulin-stimulated uptake of radiolabelled glucose was reduced by almost 50% compared with that found in chromium-replete media. This decreased response could be restored by the addition of physiologically relevant (0·3 μg/l) concentrations of inorganic chromium (P<0·001). The sensitivity of these cells to insulin was reduced dramatically by a reduction in the chromium content of the medium and was again increased (P<0·001) by chromium addition. The concentrations of chromium required to restore the sensitivity to insulin were of the same order as those found physiologically; much higher concentrations of chromium could also stimulate glucose uptake in the absence of insulin but such concentrations were supra-physiological.
Journal of Endocrinology (1995) 144, 135–141
Transforming growth factor-α: receptor binding and action on DNA synthesis in the sheep mammary gland
Authors: Moorby C D , Taylor J A , Forsyth I A 
Published: December 2008

Abstract
Microsome fractions prepared from the mammary glands of non-pregnant, pregnant and lactating sheep have been used to study binding of 125I-labelled transforming growth factor-α (TGF-α). Binding was dependent on microsomal protein concentration, time and temperature. It showed the characteristics of an epidermal growth factor (EGF) receptor, being displaced by TGF-α and EGF, but not by insulin or IGF-I. The non-linear curve fitting program LIGAND was used to determine affinity and number of binding sites. A single class of high-affinity binding sites was found. The apparent dissociation constant (Kd) was similar in all physiological states (2·43±0·27 mol/l × 10−10, n=23). Numbers of binding sites were lower in late-pregnant (20 weeks) and lactating sheep (14·07± 2·45 fmol/mg protein, n=10) than in non-pregnant, 10-or 15-week pregnant sheep (43·04±5·93 fmol/mg protein, n=13).
DNA synthesis by mammary alveolar epithelial cells cultured on collagen gels was increased twofold by TGF-a (maximum response at 10 μg/l; 1·8 nmol/l) but not by EGF. Cells derived from 15- to 20-week pregnant sheep responded significantly to TGF-α on day 3 of culture, but the response was delayed to day 4–5 of culture in cells from other physiological states. Dose–response was not significantly affected. TGF-α and IGF-I produced an additive effect on DNA synthesis. Oestradiol (10−12 to 10−9 m), a potential stimulator of the TGF-α gene, did not stimulate DNA synthesis alone, or in combination with IGF-I. It is concluded that growth factors acting via the EGF receptor play a role in ruminant mammary development, but whether they mediate oestradiol effects remains unresolved.
Journal of Endocrinology (1995) 144, 165–171