bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence that neuronally released vasoactive intestinal polypeptide inhibits the release of serotonin from enterochromaffin cells of the guinea pig small intestine
Authors: Racké Kurt , Schwörer Harald , Agoston Denis V. , Kilbinger Heinz 
Published: June 2009

Abstract.
Isolated small intestinal segments of the guinea pig were arterially perfused and the release of serotonin (5-hydroxytryptamine) and 5-hydroxyindoleacetic acid into the portal venous effluent was determined by HPLC with electrochemical detection. Test substances were intra-arterially applied. The muscarine receptor agonist oxotremorine (1 μmol/l inhibited the release of 5-hydroxytryptamine by about 50%. In the presence of the neurotoxin tetrodotoxin, oxotremorine enhanced the release of 5-hydroxytryptamine by 145%, indicating that the inhibitory effect of oxotremorine was mediated by the release of a neurotransmitter. Exogenous vasoactive intestinal polypeptide ( 1-100 pmol/l inhibited the release of 5-hydroxytryptamine by about 50%, an effect antagonized by a specific antibody to vasoactive intestinal polypeptide. This antibody to vasoactive intestinal polypeptide, on its own, had no effect on the release of 5-hydroxytryptamine. However, it prevented the inhibitory effect of oxotremorine. In the presence of the antibody to vasoactive intestinal polypeptide, unlike in the presence of tetrodotoxin, oxotremorine did not stimulate the release of 5-hydroxytryptamine. In conclusion, activation of neuronal muscarine receptors in the guinea pig small intestine enhances the release of several neurotransmitters which can inhibit the release of 5-hydroxytryptamine. The present experiments provide good evidence that vasoactive intestinal polypeptide is one of them.
Effects of exogenous monoiodotyrosine on the serum levels of anterior pituitary hormones
Authors: Tan Stanley A. , Lewis John E. , Berk Lee S. , Wilcox R. Bruce 
Published: June 2009

Abstract.
Monoiodotyrosine is a tyrosine hydroxylase inhibitor. Ingestion of one gram monoiodotyrosine caused a 10000-fold increase of serum monoiodotyrosine from basal levels of 0.69±0.20 nmol/l to a peak of 10.6±1.7 μmol/l in women and 7.1±2.3 μmol/l in men 30 min later, and the t½ was 45 min. Monoiodotyrosine stimulated PRL to a peak of 170±51 μg/l in women and 90±6 μg/l in men 30 min after the monoiodotyrosine peak, or 60 min after the ingestion. Other anterior pituitary hormones were unchanged. Dopamine infusion or L-dopa pretreatment attenuated the monoiodotyrosine effect. TRH exaggerated the PRL peak, and chlorpromazine did not increase but prolonged the hyperprolactinemia. These results suggest that dopamine synthesis inhibition may be the mechanism of PRL stimulation.
Steroid profile in serum: increased levels of sulphated pregnenolone and pregn-5-ene-3β,20α-diol in patients with adrenocortical carcinoma
Authors: Gröndal Staffan , Curstedt Tore 
Published: June 2009

Abstract.
A serum steroid profile was determined in 11 patients with adrenocortical carcinoma, 5 with adrenocortical adenoma and 10 healthy controls. Seven of the patients with carcinoma had different forms of endocrine symptoms, and of those with adenoma 3 had Cushing's syndrome and 2 primary hyperaldosteronism. Sulphated steroids dominated in serum from both patients and controls, whereas the levels of free and glucuronated steroids were low. All patients with adrenocortical carcinoma had increased levels of sulphated pregn-5-ene-3β-ol-20-one (pregnenolone) and pregn-5-ene-3β,20α-diol compared with healthy controls and patients with adrenocortical adenoma. Serum levels of 11-deoxycortisol and/or its glucuronated metabolite tetrahydro-11-deoxycortisol were clearly elevated in 8 of the patients with carcinoma. The results are in agreement with those previously found for conjugated urinary steroids in patients with adrenocortical carcinoma. Thus, an impaired function or deficiency of 3β-hydroxysteroid dehydrogenase/Δ5-4 isomerase and in some cases also of 11β-hydroxylase could explain the findings. The sulphated pregnenolone and/or pregn-5-ene-3β,20α-diol, possibly together with free11-deoxycortisol seem to be useful for preoperative discrimination between malignant and benign adrenocortical tumours.
Unaltered pulsatile and circadian TSH release in euthyroid patients with endemic goitre
Authors: Weber Peter , Krause Ulrich , Gaffga Gabi , Brabant Georg , Manz Friedrich , Lehnert Hendrik , Schrezenmeir Jürgen , Beyer Jürgen 
Published: June 2009

Abstract.
To evaluate the pathophysiological role of TSH in goitrogenesis we investigated pulsatile TSH secretion in 11 patients with a non-toxic goitre and in 11 healthy controls. Thyroid volume was 40 ± 10 ml in the goitre group and 15 ± 4 ml in the controls as measured by ultrasound. Blood was sampled continously via an indwelling venous catheter at 10-min intervals over 24 h. Neither the mean 24-h serum TSH levels (goitre 1.1 ± 0.5 vs controls 0.9 ± 0.4 mU/l) nor the nocturnal surge of TSH were significantly different between the two groups. The average of the TSH pulse frequency (goitre 10.8 ± 3.7 vs controls 9.6 ± 3.5 pulses/24-h) and of the TSH pulse amplitude (goitre 0.4 ± 0.2 vs controls 0.3 ± 0.1 mU TSH/l as analysed by DESADE programme (detection of secretory activity by discrete deconvolution) did not differ in the two groups. Furthermore, there was no correlation between the volume of the thyroid gland and the dynamics of the TSH secretion. We conclude that our data do not suggest a relevant pathophysiological role of TSH secretion in the development of non-toxic goitre in man.
Heat stress and hydrocortisone are independent stimulators of triiodothyronine-induced growth hormone production in cultured rat somatotrophic tumour cells
Authors: Shapiro Lawrence E. , Katz Claire P. , Wasserman Susan H. S. , DeFesi Charles R. , Surks Martin I. 
Published: June 2009

Abstract.
We have reported that, in cultured GC cells, the stress of incubation at 41°C enhances thyroid hormone stimulation of growth hormone (GH) in a manner similar to the effects observed in a model of nonthyroidal disease in rats. Since glucocorticoids are potentially involved in stress responses both in vivo and in cell culture, we studied the role of glucocorticoid in the enhancement of (which are rat somatotrophic tumor cells) triiodothyronine (T3)-induced GH synthesis due to heat stress. Hydrocortisone addition increased T3-induced GH synthesis and GH mRNA content in cultured GC cells at both 37°C and 41°C. Depletion of glucocorticoid endogenous to serum supplement of the tissue culture medium did not prevent the enhancement of T3-induced GH synthesis that occurred during incubation at 41°C. The levels and affinity of glucocorticoid cytosolic receptors were not enhanced during incubation at 41°C. Lastly, no change in the sedimentation coefficient of the cytosolic glucocorticoid receptor or in its translocation into the nucleus occurred during incubation at 41°C. Thus, the enhancement of T3-induced GH production in GC cells by heat stress appeared independent of the effect of glucocorticoids and not mediated through glucocorticoid receptors.
Regulation of testicular P-450 cholesterol side-chain cleavage and P-450 C17-20 lyase/C17 hydroxylase enzymes in the neonatal and adult rat
Authors: Lu Yin , McDonough Alicia A. , Farley Robert A. , Warren Dwight W. 
Published: June 2009

Abstract.
Adult Leydig cells respond to LH or hCG with an initial stimulation of testosterone secretion followed by LH receptor down-regulation and blockade of androgen biosynthesis. In contrast, fetal Leydig cells respond with increased LH receptor number and enhanced steroidogenesis. In this study, the molecular mechanisms of high-dose hCG treatment on steroidogenesis in adult and neonatal testes (containing predominantly the fetal generation of Leydig cells) were examined using two recombinant DNA clones specific for enzymes of the rat steroidogenic pathway (P-450 cholesterol side-chain cleavage enzyme, P-450scc and P-450 17α-hydroxylase/C17-20 lyase, P-450c17). We treated adult (60 days of age) and neonatal (2 days of age) rats with a single high dose of hCG (600 IU/kg), sc. The high dose of hCG caused neonatal testicular P450scc and P450c17 mRNA levels to increase, and stimulated adult testicular P450scc mRNA levels, but caused a decrease in adult P450c17 mRNA levels. These studies suggest that high doses of hCG regulate testosterone production differently in adult and fetal Leydig cells at a pretranslational level of the P450c17 enzyme, while mRNA for P450scc is stimulated in both the adult and fetal Leydig cell.
A human TSH-secreting adenoma: Endocrine, biochemical and morphological studies. Evidence of somatostatin receptors by using quantitative autoradiography. Clinical and biological improvement by SMS 201-995 treatment
Authors: Polak Michel , Bertherat Jerome , Li Jacques Y. , Kujas Michelle , Le Dafniet Michelle , Weizani Hussein , Van Effenterre Remy , Epelbaum Jacques , Turpin Gerard 
Published: June 2009

Abstract.
An invasive TSH-secreting adenoma inducing mild hyperthyroidism was diagnosed in a 16-year-old male. Initial surgical treatment led to a temporary clinical and biological improvement. Recurrence of the thyrotoxicosis was treated with the somatostatin analogue, SMS 201-995 (octreotide) with normalization of the serum thyroid hormone levels with a dose of 200 μg per day. With immunoelectron microscopy, the tumour cells appeared poorly granulated with small secretory granules located at the periphery of the cells; only part of those were immunoreactive with an anti-TSHβ monoclonal antibody. No specific TRH binding site was found in a tumour membrane preparation. By quantitative autoradiography, somatostatin specific binding sites were as numerous in the TSH-secreting tumour as in control GH-secreting tumours. Binding kinetics and guanosine triphosphate dependency of the binding were equivalent in the TSH and GH tumours tested. Although all of the tumour cells displayed the same ultrastructural features, some were non-immunoreactive, suggesting that they could secrete an altered form of TSH. The absence of TRH receptors in the tumour cells is in accordance with previous reports on this type of tumour. We confirm the efficiency of octreotide treatment in this case of neoplastic TSH inappropriate secretion. The therapeutic effect of octreotide goes along with the presence of a high density of guanine nucleotide-dependent somatostatin binding sites in the tumour cells.
Effects of cytidine 5'-diphosphocholine administration on basal and growth hormone-releasing hormone-induced growth hormone secretion in elderly subjects
Authors: Ceda Gian Paolo , Ceresini Graziano , Denti Licia , Magnani Dario , Marchini Lorenzo , Valenti Giorgio , Hoffman Andrew R. 
Published: June 2009

Abstract.
The basal and GH-releasing hormone-stimulated secretion of GH declines in the elderly. We tested the ability of cytidine 5'-diphosphocholine, a drug used in the treatment of stroke and Parkinson's disease, to alter GH secretion in 11 healthy elderly volunteers, aged 69-84. Each subject received an iv infusion of 2 g of cytidine 5'-diphosphocholine or normal saline. GHRH and TRH were also administered during cytidine 5'diphosphocholine infusions. The infusion of cytidine 5'-diphosphocholine induced a 4-fold (p<0.05) increase in serum GH levels over basal values. A small increase in GH was seen after GHRH administration. However, the addition of GHRH to the cytidine 5'-diphosphocholine infusion resulted in a GH response which was significantly greater than that seen after GHRH alone; the integrated concentration of GH was more than 2-fold greater in the cytidine 5'-diphosphocholine treated group (706.85± 185.1 vs 248.9±61.4 μg · l−1 · (120 min)−1; p=0.01). The PRL and TSH responses to TRH were not significantly affected by cytidine 5'-diphosphocholine infusion, indicating that dopaminergic mechanisms are not involved. These studies demonstrate that cytidine 5'-diphosphocholine can enhance basal and GHRH-stimulated GH release in the elderly, but the mechanism of action of the drug remains unclear.
Bone mass in totally thyroidectomized patients. Role of calcitonin deficiency and exogenous thyroid treatment
Authors: Gonzalez Diana C. , Mautalen Carlos A. , Correa Pedro H. , El Tamer Elias , El Tamer Sara 
Published: June 2009

Abstract.
Calcitonin has an uncertain role in the preservation of bone mass. Since surgical thyroidectomy abolishes the calcitonin secretion in response to calcium, the bone mineral density at the radius shaft and lumbar spine was measured in 60 patients (5 men, 16 premenopausal, 34 postmenopausal euparathyroid and 5 postmenopausal hypoparathyroid women) who had undergone near total thyroidectomy for thyroid cancer 8.4±0.7 years before the study. All patients were maintained on suppressive doses of thyroid hormones. Bone mineral density values of the radius shaft (expressed as Z-score) of 34 postmenopausal euparathyroid women was significantly below the normal average (mean ± sem = −0.59 ±0.2; p=0.01). Bone mineral density of the lumbar spine was also below the normal average although the difference only approached statistical significance (−0.36±0.2; 0.05 <p<0.1). The bone mineral density of neither the radius nor the spine differed from normal levels in the premenopausal women and the postmenopausal hypoparathyroid women. Unexpectedly, the bone mineral density of the spine was significantly increased in the 5 thyroidectomized men. The results indicate that thyroidectomized women have a diminished bone mass after the menopause only if parathyroid function is normal. Since the patients were receiving thyroid hormone at suppressive doses, the present study is not able to separate the relative contributions of calcitonin deficit and exogenous thyroid on bone mass loss.
Calf and forearm blood flow in patients with primary hyperparathyroidism and in control subjects
Authors: Broulik P. D. , Spáĉil J. 
Published: June 2009

Abstract.
Using a venous occlusion air-filled plethysmograph we measured the blood flow in the limbs in 10 patients with established primary hyperparathyroidism and control subjects. The patients had highly raised ionized calcium and immunoreactive parathormone levels, and the diagnosis was verified at operation. In all patients resting blood flow values in the limbs were increased compared with control subjects. Peak blood flow after 5 min of ischemia was also increased, however, not significantly. This clinical study supports previous studies on a vasoactive effect of parathormone.
Intact parathyroid hormone concentration and cyclic AMP metabolism in thyroid disease
Authors: Fraser W. D. , Logue F. C. , MacRitchie K. , Wilson R. M. , Gray H. W. , Beastall G. H. , O'Reilly D. StJ. 
Published: June 2009

Abstract.
In 35 thyrotoxic patients and 35 patients receiving thyroxine replacement therapy mean serum intact parathyroid hormone concentrations were lower than in euthyroid normal volunteer controls. In 20 hypothyroid patients intact PTH was increased relative to euthyroid controls. Mean serum adjusted calcium was increased in thyrotoxic patients relative to euthyroid controls and in 8 toxic patients with elevated serum adjusted calcium (>2.60 mmol/l) intact PTH was below the assay detection limit (<0.5 pmol/l). Indices of PTH activity were consistent with intact PTH measurements in thyrotoxic patients with nephrogenous cyclic adenosine monophosphate lower, tubular maximum reabsorption of phosphate higher, and urinary calcium creatinine ratio higher than controls. In hypothyroid patients these indices of PTH activity suggest relative end organ resistance to PTH with nephrogenous cyclic adenosine monophosphate similar, tubular maximum reabsorption of phosphate similar, and calcium creatinine ratio lower than in controls. In treated hypothyroid patients nephrogenous cyclic adenosine monophosphate was higher, tubular maximum reabsorption of phosphate similar, and calcium creatinine ratio higher than in controls. These results are compatible with the hypothesis that thyroid status modifies the renal responses to PTH (1-84).
HLA-DR3 and variations of the T cell receptor β gene in Graves' disease
Authors: Schifferdecker Ekkehard , Manfras Burkhard , Kühnl Peter , Holzberger Gerhard , Boehm Bernhard O. 
Published: June 2009

Abstract.
The association of Graves' disease with two allelic forms of the T cell receptor β-chain gene (Bgl II restriction fragments 9.2/10.0 kb) was analysed in Caucasians suffering from Graves' disease (N=54), randomly selected controls (N=68), and HLA-DR3 homozygous typing control subjects (N=12). While gene frequencies did not vary in the latter two groups, a significant reduction of 9.2 kb homozygosity was observed in patients with Graves' disease (11 vs 32%, x2=7.68, p<0.01, RR=0.26). The excess of the 9.2/10.0 kb heterozygosity in patients, which is restricted to the DR3-positive individuals, did not reach significance. The increase in heterozygosity of genomic T cell receptor β-chain polymorphisms may be attributed to the role the β-chain plays in autoantigen recognition in Graves' disease.
Immunoreactive insulin-like growth factor binding protein-3 in the culture of human luteinized granulosa cells
Authors: Hamori Miklos , Blum Werner F. , Török Attila , Stehle Ralph , Waibel Eberhard , Cledon Philippe , Ranke Michael B. 
Published: June 2009

Abstract.
Granulosa cells from human preovulatory follicles were cultured under serum-free conditions to investigate the presence of immunoreactive insulin-like growth factor binding protein-3 (IGFBP-3). IGFBP-3 levels were measured by a radioimmunoassay developed against the acid-stable subunit of the protein. The antiserum had no cross-reactivity to the low molecular weight GH-independent IGFBP-1. Granulosa luteal cells exhibited a continuous release of IGFBP-3 into the culture medium during the whole time (6 days) of the incubation. A dose-dependent increase in IGFBP-3 was observed when the cells were treated by dibutyryl cAMP. Cycloheximide suppressed almost completely both the basal and the stimulated production of IGFBP-3. The smallest effective dose of dibutyryl cAMP enhancing the progesterone release was lower than that for IGFBP-3. The different time course of IGFBP-3 and progesterone secretion to dibutyryl cAMP treatment, as well as the failure of progesterone to elicit IGFBP-3 increase alone, do not support the participation of progesterone in the IGFBP-3 production of granulosa cells. It is concluded that 1. immunoreactive IGFGBP-3 is produced by cultured granulosa luteal cells; 2. its synthesis is regulated by physiological intracellular mechanisms.
Beneficial effects of GH replacement therapy in adults
Authors: Christiansen Jens Sandahl , Jørgensen Jens Otto Lunde 
Published: June 2009

Abstract.
Growth hormone deficiency in adults is associated with psychosocial maladjustment, reduced muscle strength, and reduced exercise capacity. Body composition is significantly altered, with increased fat and decreased muscle volume as compared with healthy subjects. Kidney function is subnormal. Epidemiological data suggest premature mortality owing to cardiovascular disease in hypopituitary patients. Short-term GH treatment trials have shown improved psychosocial performance, normalization of body composition, increased muscle strength, improved exercise capacity, increased cardiac performance, and normalization of kidney function. Thus GH replacement therapy in GH-deficient adults exhibits potential long-term beneficial effects. A number of important questions have to be addressed before long-term GH replacement therapy in GH-deficient adults can be considered on a routine basis.
Heterogeneity of human luteinizing hormone. Hydrophobic interaction chromatographic fractionation of some preparations
Authors: van Ginkel Leendert A. , Somers Harry H. J. , Loeber J. Gerard 
Published: June 2009

Abstract.
The heterogeneity of human luteinizing hormone was investigated with high performance hydrophobic interaction chromatography on a TSK phenyl-5PW column using an ammonium sulphate gradient. Recovery of individual subunits, expressed as immunochemical activity, was in the order of 90%. Recovery of the intact hormone was less, approximately 25%. The technique appeared to be independent of the charge heterogeneity of the individual subunits. Each component as obtained by hydrophobic interaction chromatography showed considerable charge heterogeneity when studied by subsequent isoelectric focusing. Nontheless, all chromatography fractions derived from either subunit showed the same collection of isoelectric values, quantitatively only differences for the β-subunits could be detected. Heterogeneity of the individual subunits was clearly demonstrated after incubation of the preparations at 37 or 56°C. The heterogeneity of the β-subunit observed after incubation at 56°C was different to the heterogeneity after incubation at 37°C. After incubation at 56°C, an additional component, with a longer retention time, developed directly from the intact molecule. The component is unstable and is transformed to one of the components detected also after incubation at 37°C. Based on these results the existence of two populations of intact LH molecules with respect to their thermal stability is hypothesized.
Endocrine and metabolic effects of life-long food restriction in rats
Authors: Stokkan Karl-Arne , Reiter Russel J. , Vaughan Mary K. , Nonaka Keico O. , Lerchl Alexander 
Published: June 2009

Abstract.
The effects of chronic (40%) food restriction from 6 weeks of age were studied in 28-month-old male Fischer-344 rats; the results were compared with ad libitum-fed, old and young male rats at 28 and 3 months of age, respectively. Pituitary luteinizing hormone was similar in all old rats and was significantly lower than in young rats. In old ad libitum-fed, but not in food-restricted rats, serum levels of LH, testosterone and T4 were significantly lower than in young rats. Serum levels of T3 did not differ between young and old rats. Type-II 5'-deiodinase activity in brown adipose tissue was similar in both groups of old animals and was significantly depressed as compared with that in young rats. Serum levels of triglycerides were significantly depressed in food-restricted rats, but were significantly increased in ad libitum-fed rats as compared with young rats. Both groups of old rats had significantly elevated serum levels of cholesterol over that in young rats, but the level was significantly lower in food-restricted as compared to ad libitum-fed animals. The results are consistent with the notion that life-long food restriction tends to preserve the activity of many metabolic functions.
Oxytocin influences preovulatory follicular development and advances ovulation in rats
Authors: Robinson Gillian , Evans John J. 
Published: June 2009

Abstract.
Oxytocin has been shown to advance gonadotropin secretion in pro-estrus rats. The effects that oxytocin-induced changes have on the ovary were investigated in this study. Oxytocin administered to rats at proestrus 09.00 h, 10.00 h and 11.00 h advanced follicular growth, progesterone secretion, and the time of ovulation. However, both treated and control groups of rats ovulated similar numbers of oocytes and the oocytes released were of similar fertility. Because oxytocin has been shown to induce early LH and FSH release the effects of oxytocin administration on the ovary were possibly an indirect action involving the pituitary. The results of this investigation indicate that exogenous oxytocin alters, the timing but not the fertility of periovulatory events.