bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of insulin-like growth factors on human foetal, adult normal and tumour pituitary function in tissue culture
Authors: Goodyer Cynthia G. , Marcovitz Sorana , Hardy Jules , Lefebvre Yves , Guyda Harvey J. , Posner Barry I. 
Published: December 2008

Abstract. To determine the direct effects of insulin-like growth factors (IGFs) on hormone release by the human pituitary gland, human foetal, adult normal and tumour pituitary tissues were maintained in culture for 2 to 4 weeks and tested with acute (3 h) exposures to different preparations of IGF peptides. Adult normal pituitaries and adenomas were tested with a semipurified preparation of IGFs, free of immunoreactive insulin, containing IGF-I and IGF-II in a ratio of approximately 1:4. Human foetal pituitaries were tested with the semipurified IGFs as well as more purified preparations of IGF-I and IGF-II. Culture media were assayed for hGH, hPrl, hACTH and hLH using specific radioimmunoassays.
Both foetal (n = 16 (No. of pituitaries), 33 (No. of observations)) and normal adult (n = 3, 16) human pituitaries cultures responded to the semipurified IGFs (2–25 ngEq/ml for foetal and 2–4 ngEq/ml for adult pituitaries) with a significant decrease in hGH release compared to basal (P < 0.01) whereas the GH-secreting pituitary tumours showed no effect when tested with from 2 to 25 ngEq/ml (n = 8, 129, ns). The effect of IGFs on human foetal somatotrope activity was dose-related for both the semipurified IGFs (2–25 ngEq/ml, n = 16, 33) and IGF-I or IGF-II (10–100 ng/ml; n = 3, 18).
hPrl release was inhibited in the normal adult (n = 2, 12; P < 0.01) but not in the foetal (n = 2, 9; ns) pituitary cultures by 2–4 ngEq/ml of the semipurified IGFs, while the Prl-secreting pituitary tumour cultures showed variable responses to 3–4 ngEq/ml of the same IGFs preparation (a) suppression: n = 1, 14, P < 0.001; b) no effect: n = 3, 28, ns). hGH release was inhibited in one of the two mixed (GH- and Prl-secreting) tumours examined (n = 1, 10, P < 0.02) and unaffected in the other (n = 1, 14, ns), while hPrl release remained unchanged in both. The IGFs did not alter release of hLH or hACTH by either foetal or normal adult pituitaries.
Conclusions: A semipurified preparation of IGFs directly inhibited hGH release by human foetal pituitaries and hGH and hPrl release by normal adult pituitaries but had no effect on hLH or hACTH secretion. Human foetal somatotropes responded to IGF-I and IGF-II in a similar dose-dependent manner suggesting that, like in the rat, both IGF peptides can have an inhibitory influence on GH secretion. GH- and/or Prl-secreting pituitary adenomas showed a predominant lack of responsiveness to the semipurified IGFs, suggesting that the sensitivity of somatotropes and lactotropes to an IGF inhibitory influence is often abnormal in the tumour state.
Thyroid glands in patients with Graves' disease are sources of thyrotropin-binding inhibitory (TBI) activity
Authors: del Carmen Arqueros Maria , Niepomniszcze Hugo , Moreno Juliàn 
Published: December 2008

Abstract. In order to investigate the main sources of production of Graves' immunoglobulins, 4 women with Graves' hyperthyroidism, which relapsed after withdrawal of methimazole (MMI) therapy, were selected for this study. The patients underwent subtotal thyroidectomy after pre-operative treatment with MMI and Lugol's solution. Seven blood samples were obtained in each patient during surgery from: 1) a peripheral vein, immediately before neck incision; 2) the carotid artery; 3) and 4) the left and right inferior thyroid veins, respectively, before manipulation of the thyroid; 5) and 6) the left and right inferior thyroid veins, respectively, after surgical handling of the gland; 7) a peripheral vein at the end of operation.
Thyrotropin-binding inhibitory (TBI) activity was measured in all samples by a radioligand method. Serum TSH was also measured in those samples.
There was a substantial increment of TBI in the thyroid veins compared with the activity in the carotid artery. The mean TBI was significantly higher after surgical handling of the thyroid lobes. The two lobes from each gland secreted differing levels of TBI, whereas the TSH concentrations were similar in all samples from each individual patients.
We conclude that at least part of the TBI activity in patients with Graves' disease comes from the lymphocytic infiltration of the glands, and that differences in antibody production between the thyroid lobes may explain the difference in TBI activity in their respective thyroid veins.
Autoimmune-resistance in Graves' disease tissues indication of a structural and functional heterogenicity
Authors: Müller-Gärtner Hans-Wilhelm , Schneider Claus , Schröder Sören 
Published: December 2008

Abstract. Out of 256 patients with Graves' disease and a characteristically low echogenic ultrasound appearance of the thyroid gland, 12 patients (4.7%) showed additionally one single or several intrathyroidal focal alterations with high echogenicity. Their volume was 0.2 to 7.0 cm (x̄ ± sd: 1.75 ± 2.24 cm). A common characteristic of the 12 patients was a longstanding history of Graves' disease and antithyroid treatment with thiamazol or carbimazol and a mean age of 55 ± 9 (sd) years (range 42–75 years). The foci with high echogenicity had a normal or macrofollicular histological structure (mean follicle lumen diameter 119.7 μm, as proven by histology in 4 cases) which was significantly higher than follicle lumina of the surrounding Graves' disease tissue (mean follicular lumen diameter 38.3 μm; P < 0.001). The height of follicle epithelium and the nuclei cross-section area of such foci was similar to corresponding normal tissue parameter in 5 out of 7 foci. The 99mTc-uptake of the foci amounted to 40 to 80% in comparison with Graves' disease tissue. 131-iodine autoradiography, thyroglobulin immunochemistry and 125-iodine-TSH binding analysis performed in selected cases confirmed the heterogenicity of these foci.
The data provided evidence that the foci were unresponsive to TSH-receptor mediated stimulation through Graves' immunoglobulins. It is concluded that longstanding Graves' disease can be associated with tissue foci which are in a functional sense resistant to immunogenic stimulation by TSH-receptor autoantibodies.
Gonadotropin-releasing hormone agonist inhibits physiologic ovarian follicular loss in rats
Authors: Ataya Khalid , Tadros Magdy , Ramahi Alfida 
Published: December 2008

Abstract.
To study the effect of long-term use of GnRH agonists on the number and size distribution of ovarian follicles, two experiments were performed on adult female rats. Treatment was continued for 52 days in Experiment 1 and for 229 days in Experiment 2. Every sixteenth section from one ovary of each rat was examined using a light microscope attached to a BioQuant image analysis computer system. In Experiment 3, control and previously treated rats were mated with known male breeders and the number and normalcy of the offspring evaluated. The results indicate that in rats treated with GnRH agonist: 1) the total number of follicles, the number and percentage of follicles less than 35 μm in diameter were significantly higher than in the control group; 2) the number and percentage of follicles greater than 50 μm in diameter were significantly lower than control; and 3) the number of rats that got pregnant and the litter size were not significantly different from control. We conclude that GnRH agonists inhibit the physiologic process of follicle recruitment and loss and that fertility is preserved after long-treatment administration of GnRH agonists.
Endocrine abnormalities in patients with adrenal tumours incidentally discovered on computed tomography
Authors: Virkkala Anu , Välimäki Matti , Pelkonen Risto , Huikuri Kauko , Kahri Arvi , Kivisaari Leena , Korhonen Timo , Salmi Jorma , Seppälä Pentti 
Published: December 2008

Abstract.
To determine endocrine activity of adrenal tumours incidentally discovered on CT, we examined 20 consecutive patients. They underwent thorough hormonal assessment and scintigraphic scanning with radioactive cholesterol under dexamethasone suppression (19 patients). Biochemical findings compatible with cortisol hypersecretion were detected in 5 patients. One patient had reduced reserves of cortisol secretion and one had hyporeninemic hypoaldosteronism. The scintigraphy showed no uptake in 10, unilateral uptake in 4, and bilateral uptake in 5 patients. In 3 patients the finding was unilateral on CT, but bilateral on scintigraphy. Signs of autonomous cortisol production were more common among patients who had uptake on scintigraphy. At the operation of 8 patients only benign lesions were found. During the follow-up (9 to 49 months) of the 12 unoperated patients, the tumour disappeared in one and remained unchanged in the others. No changes occurred in the biochemical findings except in one patient whose cortisol response to 1 mg of dexamethasone became abnormal. Since slight hypercortisolism or a bilateral disease often exists behind an incidentally discovered adrenal tumour, we emphasize the importance of careful assessment of cortisol metabolism and a scintigraphic scanning under dexamethasone suppression in the examination of these patients.
Insulin-like growth factor I increases glomerular filtration rate and renal plasma flow in man
Authors: Guler Hans-Peter , Eckardt Kai-U. , Zapf Jürgen , Bauer Christian , Froesch E. Rudolf 
Published: December 2008

Abstract.
Recombinant IGF-I was infused sc at a dose of 20 μg · kg−1 · h−1 to 2 healthy subjects during a total of 79 h. Serum levels of IGF-I rose from 93 and 177 to 502 and 616 μg/l, respectively. Fasting blood glucose remained normal. During the infusion, glomerular filtration rate increased by 31% in subject No. 1 and by 32% in subject No.2. Concomitantly, renal plasma flow increased by 26% and 22%, respectively. Proximal and distal tubular reabsorption of fluid and sodium as determined by lithium clearance was elevated to a similar extent. When determined again one week after the end of the IGF-I infusion, all parameters of renal function had returned to baseline. Sodium excretion, body weight and blood pressure did not change. We conclude that IGF-I infused at pharmacological doses has marked effects on kidney function. Future studies will be necessary to define the clinical potential of recombinant IGF-I in the treatment of diseases characterized by impaired renal perfusion and filtration.
Expression of insulin-like growth factor receptors in primary human thyroid neoplasms
Authors: Yashiro Tohru , Ohba Yoshito , Murakami Hitomi , Obara Takao , Tsushima Toshio , Fujimoto Yoshihide , Shizume Kazuo , Ito Kunihiko 
Published: December 2008

Abstract.
The presence of IGF-I receptors was demonstrated in normal and neoplastic tissues of human thyroid. Binding of [125I]IGF-I to thyroid membranes was dependent on time and temperature of incubation, and maximal binding was achieved at 4°C and 18 h of incubation. [125I] IGF-I binding was dose-dependently displaced by unlabelled IGF-I; half-maximal inhibition occurred at concentrations of 10–20 μg/l. IGF-II and insulin had relative potencies of 5 and 1% compared with IGF-I. Scatchard analysis of binding data revealed a single class of IGF-I receptors with high affinity (Ka: 1.2–8.6 × 109 1/mol) in normal thyroid tissues. Affinity cross-linking and autoradiography demonstrated the type I IGF receptors. Specific binding of [125I] IGF-I in thyroid cancer tissues (9.69 ± 2.07% per 200 μg protein; mean ± sem, N = 8) was significantly (p <0.05) higher than that in the surrounding normal tissues (3.03 ± 0.35%, N = 8). In contrast, there was no difference in the binding between adenoma tissues (4.19 ± 0.53%, N = 5) and the adjacent normal tissues (2.94 ± 0.24%, N = 5). The higher IGF-I binding in cancer tissues was due to an increase in the binding capacity without any change in the affinity. The presence of IGF-I receptors suggests a possible role of IGF-I and its receptors in the growth of thyroid cancer cells.
Interleukin 1 induces new protein formation in isolated rat islets of Langerhans
Authors: Helqvist Steffen , Hansen Birgit Sehested , Johannesen Jesper , Andersen Henrik Ullits , Nielsen Jens Høiriis , Nerup Jørn 
Published: December 2008

Abstract.
It is hypothesized that interleukin 1 induces toxic free radical formation in pancreatic beta-cells leading to beta-cell degeneration and destruction. Therefore, isolated rat pancreatic islets were examined for interleukin 1 and heat shock induced proteins. After exposure to human interleukin 1β (0.015 to 10 μg/1) or heat (40°C) for up to 24 h, islets were labelled with 35S-methionine and solubilized. Islets proteins were analysed by SDS-polyacrylamide gel electrophoresis. By autoradiography it was shown that both interleukin 1 and heat exposure induced the formation of a 70 kD protein. Further, interleukin 1 induced the formation of two proteins of 32 and 80 kD, respectively, which was not seen after heat exposure. Possibly, the 70 kD protein is a member of the heat shock protein 70 family, participating in unspecific cellular defence and maybe free radical scavenging. Other candidates are the superoxide radical scavenging enzyme manganous superoxidedismutase, MHC class II molecules, and heme oxygenase.
Insulin-like growth factor I binding proteins in dairy cows, calves and bulls
Authors: Ronge Harald , Blum Jürg W. 
Published: December 2008

Abstract.
Our objective was to measure relative amounts and distributions of serum IGF-I binding proteins and concentrations of hormones and metabolites in dairy cows during the dry period and during lactation, as well as in calves and in growing bulls. Concentrations of IGF-I were lower in cows during lactation than during the dry period. Concentrations of IGF-I, growth hormone, insulin, T3, T4 and glucose were higher in calves and bulls as compared with cows, whereas concentrations of non-esterified fatty acids, urea, protein and albumin were lower. Three different IGF-I binding protein fractions were found with apparent molecular weights of >200, 140–160 and 45–65 kD. Relative amounts of IGF-I binding proteins were similar, although great differences in hormones and metabolites were found in cows, bulls and calves. Accessible binding sites were higher in dairy cows than in calves and bulls, mainly owing to the fact that dairy cows had lower concentrations of IGF-I bound to these fractions. Additionally, we found significant negative correlations between total accessible binding sites and total IGF-I concentrations. There were significant differences in the distribution of binding proteins. In particular, there was a shift of binding ability from the 140–160 to the 45–65 kD binding sites from the end of pregnancy to early lactation. Amounts of IGF-I bound to proteins increased from lactating to dry cows and calves and were highest in bulls. IGF-I levels in the >200 kD fraction was lower in lactating than in dry cows, and lower in cows than in calves and bulls. IGF-I measured in the 140–160 kD fraction was lowest in lactating cows and comparable in dry cows, calves and bulls. Concentrations of IGF-I in the 45–65 kD fraction were lowest in cows and highest in bulls. In conclusion, there were marked differences in growing, pregnant and lactating cattle, particularly as concerns accessible protein binding and amounts of IGF-I bound to proteins.
High frequency of cancer in cold thyroid nodules occurring at young age
Authors: Belfiore Antonino , Giuffrida Dario , La Rosa Giacomo L. , Ippolito Orazio , Russo Giovanna , Fiumara Antonio , Vigneri Riccardo , Filetti Sebastiano 
Published: December 2008

Abstract.
In order to evaluate the risk of malignancy of cold thyroid nodules occurring in young as compared with adult patients, we studied a consecutive series of 2327 patients with a solitary cold thyroid nodule over a 6-year period. None of these patients had been previously irradiated in the neck or head. Fine needle aspiration of the nodule and cytologic examination were carried out in all patients and, on the basis of this evaluation and clinical examination 391 patients were selected for surgery; 109 patients were 4–20 years old and 2218 patients were older than 20 years. Malignancy was found in 11 (10.1%) and in 112 (5.0%) of cold thyroid nodules occurring in young and adult patients, respectively. The annual incidence of cold thyroid nodules in the population of the area studied was 5.2 vs 55.9 (per 105 inhabitants) in the young and in the adult group, respectively, and the annual incidence of thyroid cancer was 0.53 vs 2.82 (per 105 inhabitants) in the young and in the adult patients, respectively. The present study indicates, therefore, that in the absence of head or neck irradiation, cold thyroid nodules are much less frequent in young age, but that the malignancy rate of cold nodules occurring in young patients is 2-fold higher than in adults patients
Thyroid hormone and not growth hormone is the principle regulator of mammalian mitochondrial biogenesis
Authors: Mutvei A. , Husman B. , Andersson G. , Nelson B. D. 
Published: December 2008

Abstract.
T3 and GH have been implicated in the regulation of mitochondrial biogenesis. Since thyroid hormone promotes the synthesis of growth hormone, its control of human mitochondrial biogenesis could arise through a permissive action on GH biosynthesis. This was studied in hypophysectomized rats treated with T3 and/or human GH by the continuous infusion of hormone for 6 days from mini-infusion pumps implanted sc. Increases in mitochondrial respiration, enzyme activites, and protein synthesis were found in isolated liver mitochondria from rats receiving T3. In contrast, GH alone had no effect, nor did it increase the response to T3. Since it has been argued that mitochondrial biogenesis results from a direct interaction (binding) of GH with mitochondria, GH-specific binding sites were measured with 125I-bGH, a specific somatogenic receptor ligand, in isolated mitochondrial membranes in vitro. In addition, the intracellular endocytic uptake of 125I-bGH injected in vivo was compared in purified subcellular membrane fractions and mitochondria. No evidence in favour of specific GH interaction on mitochondrial membranes was found by either test. It is concluded that T3 exerts a direct, rather than permissive, effect on mitochondrial biogenesis, and that high affinity binding sites for GH are not present in rat liver mitochondria.
Effects of vasoactive intestinal polypeptide, TRH, and dopamine on prolactin secretion in estrogen-primed postmenopausal women
Authors: Couzinet Béatrice , Dorey François , Schaison Gilbert 
Published: December 2008

Abstract.
Prolactin secretion is influenced by at least three important hypothalamic neurotransmitters: TRH, vasoactive intestinal polypeptide and dopamine. The purpose of this study was to determine whether, in estradiol-primed postmenopausal women, the PRL response to TRH, vasoactive intestinal polypeptide, and dopamine differed. Ten postmenopausal women were studied during treatment with estradiol benzoate at a dose of 0.625 mg per day during 15 days. TRH (200 μg iv), saline infusion, vasoactive intestinal polypeptide (75 μg infused iv during 15 min), coadministration of vasoactive intestinal polypeptide and TRH, and dopamine (4 μg · kg−1 · min−1 iv for 3 h) were administered for 5 consecutive days before and during the last 5 days of estradiol benzoate treatment. Before estradiol benzoate administration, the PRL response to TRH was significantly greater than that of vasoactive intestinal polypeptide. Estradiol benzoate treatment increased significantly the PRL release induced by TRH (p < 0.01), but did not modify the response to vasoactive intestinal polypeptide. At the end of estradiol benzoate treatment, the maximal increase in PRL after the combined (vasoactive intestinal polypeptide + TRH) test was greater than that obtained with TRH alone and occurred earlier (p < 0.04). Dopamine suppressed PRL secretion to a similar extent after estradiol benzoate treatment. Thus: 1) in postmenopausal women, estrogens act as stimulators of PRL release; 2) estrogens are able to increase TRH-stimulated PRL secretion but not the response to vasoactive intestinal polypeptide and to reveal the additive effect of TRH and vasoactive intestinal polypeptide; 3) estradiol does not modify the effectiveness of dopamine as an inhibitor of PRL secretion; 4) these results suggest different intracellular mechanisms of the action of TRH, vasoactive intestinal polypeptide and dopamine on PRL secretion.
Heterogeneity of pituitary adenoma cell subpopulations from acromegalic patients obtained by Percoll density gradient centrifugation
Authors: Hofland Leo J. , van Koetsveld Peter M. , Verleun Theo M. , Lamberts Steven W. J. 
Published: December 2008

Abstract.
Pituitary adenoma cells from 6 acromegalic patients were separated on continuous Percoll density gradients according to differences in their density. Two adenomas produced GH only in culture, the other 4 adenomas produced either GH and PRL (one adenoma) or GH and α-subunit (one adenoma) or GH, PRL and α-subunit (2 adenomas). The cell subpopulations obtained by this technique differed in the amount of hormone production per 105 cells: GH release decreased from the low density fractions to the higher density fractions in 5 of 6 adenomas. Intracellular GH levels completely followed this profile. In the mixed GH/α-subunit adenomas the α-subunit profile completely paralleled the GH profile, whereas in the mixed GH/PRL adenomas the PRL profile showed a pattern different from that of GH (and α-subunit). In neither of the adenomas did we find any differences between the subpopulations with respect to the responsiveness of GH, PRL or α-subunit release to GHRH, TRH and the somatostatin analogue SMS 201-995. Conclusions: 1. Within pituitary adenomas from acromegalic patients heterogeneity exists with respect to hormone production per cell. 2. The cell subpopulations obtained by density gradient centrifugation are not different in their responsiveness to SMS 201-995, GHRH or TRH. 3. Because GH and α-subunit release by the fractions from the mixed GH/α-subunit secreting adenomas were completely parallel, further evidence for co-release of GH and α-subunit by the same tumoural cells is provided.
Expression and function of protein kinase C isozymes
Authors: Huang Kuo-Ping , Huang Freesia L. , Nakabayashi Hiroki , Yoshida Yasuyoshi 
Published: December 2008

Abstract.
Three protein kinase C (PKC) isozymes, type I, II, and III, have been identified as the major Ca2+/phospholipid-stimulated protein kinases in the various animal tissues. Based on the immunochemical analysis it was demonstrated that PKC I was encoded by γ cDNA, PKC II by the alternatively spliced βI and βII cDNAs, and PKC III by α cDNA. The expression of these enzymes appears to be tissue-specific and developmentally regulated. The central nervous system expresses high level of all three isozymes and the peripheral tissues mainly PKC II and III. During brain development, the expression of PKC I appears to follow the progress of synaptogenesis, whereas PKC II and III increase progressively from fetus up to 2–3 weeks of age. The level of PKC I in adult brain is highest in the cerebellum, hippocampus, amygdala, and cerebral cortex especially in those cortical regions being important for visual information processing and storage. The role of PKC II and III in cellular regulation was investigated by treatment of rat basophilic leukemia cells with the phorbol ester, phorbol 12-myristate 13-acetate. This phorbol ester caused a faster degradation of PKC II than III, indicating a differential down-regulation of these two enzymes by this compound. The results presented in this study support the contention that each species of PKC has a distinct function in the regulation of a variety of cellular processes.