bluuebunny/crossref_metadata_2025_split huggingface dataset:
Circadian, ultradian, and episodic gonadotropin and prolactin secretion in human pseudocyesis
Authors: Bray Mary A. , Muneyyirci-Delale Ozgul , Kofinas George D. , Reyes Francisco I. 
Published: June 2009

Abstract.
Six women with pseudocyesis were studied by 15-min blood sampling for 12 to 24 h to determine their gonadotropin and PRL secretory profiles aiming to clarify the endocrine alterations in this form of hypothalamic amenorrhea. Clinical and biochemical evidence of hyperandrogenism was found in 4 patients. Persistent hyperprolactinemia was present only in one patient. Significant circadian and ultradian periodicities were identified by time series analysis in the 12-24 h profiles of FSH, LH and PRL secretion. Pulse analysis by the Van Cauter (UL-TRA.JN) method revealed a 24-h mean LH interpulse interval of 91±21 min with a mean LH amplitude of 5.4±0.8 IU/l. There was a significantly lower pulse frequency at night than during the daytime. The mean 24-h PRL interpulse interval and pulse amplitude were 134±22 min and 9.2±1.8 IU/l, respectively. Both FSH and LH mean levels were higher during the daytime than at night, while the reverse was true for PRL values. Decreased LH pulse frequeny and amplitude emerged as the most distinctive findings. Antecedent hypothalamic-pituitary aberrations due to other endocrinopathies and the timing of the hormonal assessment (e.g. recovery phase) may explain, at least in part, the reported heterogeneity of neuroendocrinologic findings in pseudocyesis.
The effect of insulin withdrawal on intermediary metabolism in patients with diabetes secondary to chronic pancreatitis
Authors: Larsen Steen , Hilsted Jannik , Philipsen Else K. , Tronier Bente , Nielsen Meta Damkjær , Worning Helge 
Published: June 2009

Abstract.
Insulin was withdrawn from 7 patients with Type I (insulin-dependent) diabetes and 4 patients with insulin-dependent diabetes secondary to chronic pancreatitis, both groups without residual beta-cell function. Median plasma glucagon concentrations rose slightly, but significantly after withdrawal of insulin in Type I diabetic patients (from 14 (range: 11-16) to 19 (14-25) pmol/l by 6 h), but not in the patients with secondary diabetes. This was accompanied by a significantly higher increase in blood glucose concentration from 5.1 (4.9-5.7) to 15.2 (12.9-18.1) mmol/1 by 6 h in Type I diabetic patients compared with patients with secondary diabetes (from 4.9 (4.3-6.7) to 13.1 (10.9-13.5) mmol/l) (p<0.01). Beta-hydroxybutyrate increased to a similar extent in the two groups, whereas no significant increases were found in glycerol and lactate in any of the groups. Increased secretion of glucagon is not essential for the development of hyperglycemia and ketonemia in patients with diabetes secondary to chronic pancreatitis, but may augment the degree of hyperglycemia in Type I diabetic patients compared with patients having secondary diabetes.
Mitotane increases the blood levels of hormone-binding proteins
Authors: van Seters Arnoud P. , Moolenaar Abraham J. 
Published: June 2009

Abstract.
In 3 patients with adrenocortical carcinoma the effects of long-term mitotane therapy on the serum levels of three hormone-binding globulins and vitamin D-binding protein were studied. Within the first month of treatment cortisol-binding globulin increased two to three times, in close correlation with sex hormone-binding globulin. The rises in thyroxine-binding globulin and vitamin D-binding protein were considerably less. Elevated cortisol-binding protein appeared to be associated with increased binding of cortisol, whereas the binding of thyroxine and vitamin D remained below normal. Binding proteins returned to normal in 2 patients within a year after mitotane discontinuation. This phenomenon of hormone-binding protein enhancement invalidates the use of total serum hormone levels to monitor the effects of mitotane on endocrine function and could provide an explanation for the increased cortisol substitution requirement during mitotane therapy.
Clinical evaluation of new assays for determination of serum calcitonin concentrations
Authors: Weissel M. , Kainz H. , Tyl Eva , Ogunyemi E. , Woloszczuk W. 
Published: June 2009

Abstract.
In order to test the clinical usefulness of new commercially available kits for determination of calcitonin serum concentrations, we investigated the family (N=10) of a patient with medullary thyroid carcinoma and bilateral pheochromocytoma including his affected son, 10 athyreotic patients, totally thyroidectomized for non-medullary thyroid cancer, and 4 normal volunteers. Pentagastrin tests were performed in all subjects. Serum calcitonin levels before and after pentagastrin were determined by 4 kits. Kits A and B are immunoradiometric assays of the sandwich-type, kits C and D are radioimmunoassays, D being the one hitherto routinely used. Our results show that the new assays (kits A, B and C) have a better diagnostic accuracy in screening for medullary thyroid cancer than the RIA (kit D), hitherto used, where basal values overlapped with normals. Although basal values of normals were mostly near the detection limit of all 4 kits, kits A and B were sensitive enough to detect stimulation of calcitonin secretion by pentagastrin in all subjects with intact thyroid glands and kit C in most of them. The lack of increase in calcitonin after pentagastrin observed by kits A, B and C in athyreotic patients suggests deficiency of secretion of this hormone. Only kit D was unable to show this deficiency.
Evidence for dopamine-related and TRH-related pituitary TSH and PRL pools in patients with prolactinoma
Authors: Hanew Kunihiko , Utsumi Atsushi , Sugawara Akira , Shimizu Yasuyuki , Yoshinaga Kaoru 
Published: June 2009

Abstract.
The sources of TSH, which was excessively released by sulpiride (dopamine D2 receptor antagonist), were studied in 15 female patients with PRL-secreting adenoma (18-43 years). Sequential 3-day administration of sulpiride (100 mg, im) was given to 12 patients with prolactinoma and 6 normal female subjects (19-24 years). Patients with prolactinoma showed much greater TSH responses than normal subjects on the first day. However, TSH responses to sulpiride disappeared on the 2nd and 3rd day in both groups. In contrast, plasma PRL responses to the 1st sulpiride administration were smaller in patients with prolactinoma than in normal subjects, and the response disappeared following the 2nd administration in both groups. When TRH (500 μg, iv) was administered 120 min after the 3rd sulpiride injection, TSH and PRL increments were not different from those before the sulpiride injection in both patients with prolactinoma (N=6) and normal subjects (N=6) Further, combined administration of sulpiride and TRH in 5 patients with prolactinoma clearly enhanced the TSH and PRL responses compared with the single administration of each agent. These results suggest that there may be two readily releasable pituitary TSH and PRL pools, i.e. one dopamine-related and the other TRH-related, in patients with prolactinoma and normal female subjects.
Intracerebral administration of insulin-like growth factor I decreases circulating growth hormone levels in the fetal pig
Authors: Spencer G. S. G. , Macdonald A. A. , Buttle H. L. , Moore L. G. , Carlyle S. S. 
Published: June 2009

Abstract.
Radioimmunoassayable IGF-I levels were measured in the cerebrospinal fluid and plasma of pig fetuses at 94 days gestational age. Mean plasma IGF-I levels were 128.5 ± 5.8 μg/l while the concentration in the cerebrospinal fluid was 25.8 ± 4.4 μg/l. The effect of intracerebroventricular administration of IGF-I on circulating GH levels was also studied in pig fetuses in utero. Eighteen pig fetuses were fitted with indwelling carotid artery and juglar vein catheters. Nine fetuses were given 1500 ng of pure IGF-I in 100 μl 0.9% saline by direct injection into a right lateral ventricle. Nine further fetuses (controls) were similarly given 100 μl of saline without IGF-I. GH levels in the control fetuses were ~200 μg/l and showed marked fluctuations with episodic intervals of about 40 min. By contrast, in the IGF-I-treated fetuses, GH levels were dramatically lowered by 20 min after IGF administration and remained low throughout the 4-h study. The episodic variations in GH were abolished and levels remained fairly constant at ca. 40 μg/l. From these results we surmise that the low levels of IGF-I in the fetus may contribute to their high GH levels. At this stage it is not possible to identify whether the IGF-I inhibition is a direct effect on the pituitary or is mediated by increased somatostatin, decreased GHRH or both.
Triiodothyronine and insulin effects on malic enzyme in hypothyroid and diabetic rats
Authors: Ortiz-Caro Javier , Jolin Trinidad 
Published: June 2009

Abstract.
We examined the effects of T3 and insulin on the activity of hepatic mitochondrial α-glycerophosphate dehydrogenase and cytosolic malic enzyme in control, thyroidectomized, thyroidectomized food-restricted, and thyroidectomized diabetic rats. In the three untreated thyroidectomized groups, the decrease in hepatic nuclear T3 content was accompanied by a marked reduction in the levels of α-glycerophosphate dehydrogenase and malic enzyme activity. Although the levels of both enzymes were increased by a receptor-saturating dose of T3, the α-glycerophosphate dehydrogenase response in the thyroidectomized groups was almost identical to that in controls, whereas that of malic enzyme was reduced to 45-62% of control values. Insulin failed to stimulate the α-glycerophosphate dehydrogenase levels in untreated and T3-treated thyroidectomized groups, but caused an increase in malic enzyme activity by 79-130% in untreated thyroidectomized groups, and enhanced the activity of this enzyme to about twice that seen with T3 alone. These effects were independent of changes in nuclear T3 binding parameters. The data suggest that insulin may act on malic enzyme synthesis through its general stimulatory effect on protein synthesis, or by antagonizing factors that inhibit the induction of this enzyme.
Influence of interleukin 6 on the function of secondary cultures of human thyrocytes
Authors: Rasmussen Å. Krogh , Kayser L. , Bech K. , Feldt-Rasmussen U. , Perrild H. , Bendtzen K. 
Published: June 2009

Abstract.
Interleukin 6 has been suggested as second mediator of the effects of interleukin 1 in some cell systems. Interleukin 1 has previously been shown to inhibit the function of human thyrocytes in secondary cultures. We have therefore studied the influence of interleukin 6 (10−1−5·107 U/l) on the function of thyroid cells. Recombinant interleukin 6 slightly inhibited the production of cAMP, but failed to influence the production of thyroglobulin or the DNA content. Endotoxins (lipopolysaccharides from Salmonella abortus equi or Yersinia enterocolitica) had only a slightly inhibitory effect on thyroid cell functions, and the effect of interleukin 6 could not by itself be explained by endotoxin contamination. The effect of interleukin 6 did not mimick effects on thyroid cells afforded by recombinant interleukin 1α and 1β. Furthermore, antibodies to interleukin 6 were not able to inhibit the interleukin 1β-induced inhibition of thyroid cell functions. In conclusion, it is unlikely that interleukin 6 by itself mediates the biological effects of interleukin 1 on human thyroid cells.
Osmoregulation of systemic vasopressin release during long-term glucocorticoid excess: A study in dogs with hyperadrenocorticism
Authors: Biewenga Wim J. , Rijnberk Ad , Mol Jan A. 
Published: June 2009

Abstract.
In 9 dogs with pituitary-dependent hyperadrenocorticism and in 6 dogs with hyperfunctioning adrenocortical tumours, the osmoregulation of arginine vasopressin (AVP) release was investigated by iv infusion of 20% NaCl for 2 h at a rate of 0.03 ml per kg body weight. The responses were analysed in terms of sensitivity and threshold of the osmoregulation of AVP secretion. The sensitivity was normal in 6 dogs and lowered in 9. In 4 of the latter dogs there was complete absence of a response to hypertonicity. The osmotic threshold of AVP release was raised in 9 dogs and normal in 2 dogs, whereas in the four dogs without any response the term threshold was not applicable. The results were not different for dogs with pituitary-dependent hyperadrenocorticism and dogs with hyperfunctioning adrenocortical tumour. It is concluded that corticosteroid excess per se induces a marked impairment of the osmoregulation of AVP secretion. The loss of reactivity of the osmoreceptor system may contribute to the corticosteroid-induced polyuria, which is also the result of resistance to AVP in the kidney.
Enhancement by growth hormone of phorbol diester-stimulated respiratory burst in human polymorphonuclear leukocytes
Authors: Spadoni Gian Luigi , Spagnoli Anna , Cianfarani Stefano , Del Principe Domenico , Menichelli Adriana , Di Giulio Stefano , Boscherini Brunetto 
Published: June 2009

Abstract.
The oxidative metabolic burst of mononuclear and polymorphonuclear phagocytes can be stimulated to produce free oxygen radicals. Several substances can enhance this respiratory burst activity by a priming action: recently growth hormone (rat and porcine) was demonstrated to act as a priming agent on rat peritoneal and on porcine alveolar macrophages. In our study we wanted to verify whether also human GH had a similar priming action on homologous cells, in particular on polymorphonuclear leukocytes. To determine the oxidative activity of polymorphonuclear leukocytes, after stimulation with phorbol myristate acetate, a flow-cytometric assay was employed which registered the intracellular formation of highly fluorescent products as indicators for the intracellular formation of hydrogen peroxide. The incubation of phorbol myristate acetate-stimulated polymorphonuclear leukocytes with GH resulted in a time-dependent and dose-dependent increase in fluorescence, thus demonstrating that human GH enhances in vitro the oxidative metabolic burst of these cells. The action of GH appeared to be significant after 30 min of incubation, was maximal at 60 min, and decreased after 90 min. After one hour of incubation, the first significant variation of fluorescence appeared with GH at a concentration of 50 μg/l. The maximum effect was seen at 100 μg/l with no further increase. Specificity of GH action was demonstrated by the inhibition of its effect by the addition of monoclonal antibodies to GH.
Effect of diabetes mellitus on levels of atrial natriuretic hormone in plasma and the right atrium in the non-obese diabetic mouse
Authors: Yano Shuichi , Tanigawa Keiichiro , Suzuki Shusaku , Kobayashi Yuta , Shimada Toshio , Morioka Shigefumi , Kato Yuzuru , Moriyama Katsutoshi 
Published: June 2009

Abstract.
Atrial natriuretic hormone (ANH) levels in plasma and the right atrium of non-bose diabetic mice in the decompensated diabetic state were investigated by radioimmunoassay and histological examination. Severely diabetic mice, with blood glucose levels over 33.6 mmol/l showed significantly higher hematocrit, plasma sodium and calculated plasma osmolarity than the age-matched normoglycemic mice. The plasma ANH levels in diabetic mice were significantly lower (17.5 pmol/l than those in normoglycemic mice (43.6 pmol/l). The ANH concentrations in the right atrium were 26.6 mg/g protein in the diabetic and 11.2 mg/g protein in the normoglycemic mice. The right atrium in the diabetic mice showed much wider immunohistochemical staining by anti-human ANH antiserum compared with the normoglycemic mice. An increase in the number of atrial specific granules in the diabetic mice was observed by transmission and scanning electron microscopy. Morphometrical analysis indicated that the number of granules increased to more than twice that in the normoglycemic mice. These findings indicate that plasma ANH decreases in diabetic mice. The store of right atrial ANH may be increased to compensate for the marked dehydration in severe diabetes.
The role of histamine in the neuroendocrine regulation of pituitary hormone secretion
Authors: Knigge Ulrich , Warberg Jørgen 
Published: June 2009

Abstract.
The neurotransmitter histamine participates in the neuroendocrine regulation of pituitary hormone secretion by an indirect action at a hypothalamic level where histaminergic neurons are abundant. The effect of histamine is caused by activation of postsynaptic H1- or H2-receptors. Histamine stimulates the secretion of ACTH, β-endorphin (mediated by CRH and AVP), α-MSH (mediated by dopamine and peripheral catecholamines), and PRL (mediated by dopamine, serotonin and AVP), and participates in the stress-induced release of these hormones and possibly in the suckling- and estrogen-induced PRL release. The release of GH and TSH is predominantly inhibited by histamine; however, uncertainty exists regarding its role and the hypothalamic factors involved. Histamine increases the secretion of LH in females (mediated by GnRH), and may be involved in the mediation of the estrogen-induced LH surge. AVP and oxytocin are stimulated by histamine, probably by an effect in the supraoptic and paraventricular nuclei of the hypothalamus.
Comparison of acid ethanol extraction and acid gel filtration prior to IGF-I and IGF-II radioimmunoassays: Improvement of determinations in acid ethanol extracts by the use of truncated IGF-I as radioligand
Authors: Bang Peter , Eriksson Ulla , Sara Vicki , Wivall Inga-Lena , Hall Kerstin 
Published: June 2009

Abstract.
Insulin-like growth factor binding proteins interfere in the IGF-I and -II radioimmunoassays. In an attempt to overcome this problem, we have compared the use of truncated IGF-I, with reduced IGFBP affinity, and IGF-I as radioligands for IGF-I RIA measurements in serum separated by acid gel filtration or acid ethanol extraction followed by cryo-precipitation. With truncated IGF-I as radioligand the IGF-I measurements in acid gel filtrates and acid ethanol extracts were significantly correlated in healthy subjects (N=42, r=0.91, p<0.001) and in patients with acromegaly (N=10, r=0.85, p<0.01), GH deficiency (N=10, r=0.88, p<0.001) or Type I diabetes mellitus (N=10, r=0.90, p<0.001). In contrast, the IGF-I concentrations in acid ethanol extracts determined with IGF-I as radioligand did not correlate with those in acid gel filtrates using truncated IGF-I radioligand in patients with acromegaly (r=0.61, NS) or GH deficiency (r=0.46, NS). In the latter group the mean IGF-I concentrations measured in acid ethanol extracts were erroneously elevated by 112%. Low-affinity antibodies used for IGF-II RIA determinations failed to give reliable results in acid ethanol extracts from patients with Type I diabetes mellitus or GH deficiency. In conclusion, erroneously high IGF-I concentrations owing to binding of the radioligand to IGFBPs not completely removed by acid ethanol extraction can be avoided by the use of truncated IGF-I as radioligand.
Predominant intraepithelial localization of primed T cells and immunoglobulin-producing lymphocytes in Graves' disease
Authors: Paschke R. , Brückner N. , Schmeidl R. , Pfiester P. , Usadel K. H. 
Published: June 2009

Abstract.
It has been proposed that intrathyroidal lymphocytes, localized in specific anatomical sites might have distinct, pathophysiologically relevant functions in Graves' disease. However, most studies of intrathyroidal lymphocytes were restricted to two lymphocyte locations and used semiquantitative methods. Therefore we used seven anatomically different lymphoid compartments to classify and evaluate by quantitative representative methods the total intrathyroidal lymphocytic infiltration and the staining indexes for immunoglobulin-producing plasmocytes and primed T cells (CD45RO), which provide maximum help to pokeweed mitogen-stimulated immunoglobulin synthesis in 36 thyroid glands from patients with Graves' disease. We found only 3.4% of all intrathyroidal lymphocytes intraepithelially. However, only intraepithelial lymphocytes showed a significantly higher staining index for primed T cells compared with several other compartments. There was also a high staining index for immunoglobulin-producing lymphocytes in this compartment. Kappa- and lambda-positive plasmocytes were found in a polyclonal distribution (kappa:lambda=64.1: 35.9) in all compartments. This increased incidence of CD45RO-positive T lymphocytes and of immunoglobulin-producing lymphocytes among the intraepithelial lymphocytes suggests a distinct pathophysiological function of lymphocytes in peripolesis in Graves' disease. Furthermore, there is a polyclonal intrathyroidal immunoglobulin synthesis.
Insulin resistance, but normal basal rates of glucose production in patients with newly diagnosed mild diabetes mellitus
Authors: Hother-Nielsen Ole , Beck-Nielsen Henning 
Published: June 2009

Abstract.
Fasting hyperglycemia in Type II (non-insulin-dependent) diabetes has been suggested to be due to hepatic overproduction of glucose and reduced glucose clearance. We studied 22 patients (10 lean and 12 obese) with newly diagnosed mild diabetes mellitus (fasting plasma glucose <15 mmol/l, urine ketone bodies <1 mmol/l), and two age- and weight-matched groups of non-diabetic control subjects. Glucose turnover rates and sensitivity to insulin were determined using adjusted primed-continuous [3-3H]glucose infusion and the hyperinsulinemic euglycemic clamp technique. Insulin-stimulated glucose utilization was reduced in both diabetic groups (lean patients: 313±35 vs 531±22 mg·m−2·min−1, p<0.01;obesepatients:311±28vs453±26mg·m−2·min−1, p<0.01). Basal plasma glucose concentrations decreased 0.43±0.05 mmol/l per h (p<0.01). Glucose production rates were smaller than glucose utilization rates (lean patients: 87±3 vs 94±3 mg·m−2·min−1, p<0.01; obese patients: 79±5 vs 88±5 mg·m−2 ·min−1, p<0.01), were not correlated to basal glucose or insulin concentrations, and were not different from normal (lean controls: 87±4 mg·−2·min−1; obese controls: 80±5 mg·m−2·min−1). These results suggest that the basal state in the diabetic patients is a compensated condition where glucose turnover rates are maintained near normal despite defects in insulin sensitivity.
Sleep deprivation reduces LH secretion in men independently of melatonin
Authors: Strassman RickJ. , Qualls Clifford R. , Lisansky E.Jonathan , Peake Glenn T. 
Published: June 2009

Abstract.
Melatonin affects gonadal function in nonprimate mammals. Confirmatory data in man are not available. We assessed melatonin's acute effects on luteinizing hormone secretion in 17 normal men. We studied these men in conditions of sleep in the dark, and sleep deprivation in bright light, dim light, and bright light combined with a physiologically relevant infusion of melatonin, while measuring blood levels of immunoreactive LH every 20 min for 7 h. We compared overnight LH secretion, and LH pulse frequency, amplitude, length, interval and area under the curve using a modification of the PULSAR peak identification program, among the four treatments. Areas under the curve for peaks in all three conditions of sleep deprivation were lower than in normal sleep. The presence or absence of melatonin had no additional effect. We conclude that acute suppression of melatonin does not affect LH pulse parameters in normal man, but that sleep deprivation may reduce the amount of LH secreted per pulse.