bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oestrogens induce an LH surge in a prepubertal patient with 45,X gonadal dysgenesis under prolonged pulsatile LRH administration
Authors: Delemarre-van de Waal Henriette A. , Van den Brande J. L. , van Kessel H. , Schoemaker J. 
Published: December 2008

Abstract.
A nine year old prepubertal patient with 45,X gonadal dysgenesis received pulsatile LRH administration for 3 weeks, every 90 min 10 μg iv. In the first week LH and FSH levels increased from prepubertal levels into the castrate range. Under 2.5 μg ethinyloestradiol (EE) LH levelled off for 3 days, followed by an LH surge. FSH showed an ethinyloestradiol dose-dependent decrease. These data suggest that: 1) pulsatile LRH administration may help to distinguish prepubertally those Turner patients with potential ovarian function from those without; 2) oestrogens exert both a negative and positive feedback action at the pituitary level in the LRH treated human; 3) the pituitary does not need 'pubertal maturation' for developing positive feedback to oestrogens. This supports the notion that pubertal maturation is confined to suprapituitary changes.
Effects of capture and venipuncture on serum levels of prolactin, growth hormone and cortisol in outdoor compound-housed female rhesus monkeys (Macaca mulatta)
Authors: Blank Michael S. , Gordon Thomas P. , Wilson Mark E. 
Published: December 2008

Abstract.
The effects of capture and repeated venipuncture on serum levels of prolactin (Prl), growth hormone (GH) and cortisol (F) were assessed in outdoor, open compound-housed, socially-living female rhesus monkeys. In animals unaccustomed to capture, blood samples obtained soon after capture (time zero) contained relatively high concentrations of both Prl and GH (Prl>30 ng/ml, GH> 10 ng/ml) which declined dramatically over the next 60 min. Mean levels of serum Prl in capture-naive lactators (n=6) and non-lactators (n=5) were 83 ± 28 (sem) and 32 ± 11 ng/ml at time zero and fell significantly (P < 0.01) within 60 min to 28 ± 10 and 6 ± 2 ng/ml, respectively. GH levels in serum also decreased over time and the time-dependent reductions in serum Prl and GH were unaffected by intervening venipuncture or caging. In contrast, serum F rose after capture reaching peak values (330 – 515 ng/ml) 60 min later. The delayed rise in serum F could reflect the time required for pituitary trophic stimulation of the adrenals after capture. Capture-acclimated, lactating females displayed lower levels of Prl at time zero with values approximating those found at 90 min in the capture-naive group. Furthermore, capture-acclimated pregnant animals exhibited a significant rise in Prl levels after parturition in the spring. These studies suggest a non-specific, capture-related release of pituitary hormones in capture-naive, compound-housed female rhesus. However, animals that have been captured and bled repeatedly over some weeks or months show lower, physiological levels of Prl, indicating an acclimation to the procedure. Thus, outdoor-housed rhesus monkeys which have been acclimated to capture can be a useful model for studying the involvement of Prl in reproduction in this species.
Dopaminergic regulation of 18-hydroxycorticosterone and aldosterone secretion in man
Authors: Sowers James R. , Beck Frances W. J. 
Published: December 2008

Abstract.
This study was designed to investigate dopaminergic mechanisms involved in the control of corticosteroid secretion. Plasma renin activity (PRA), prolactin, cortisol, corticosterone, 11-deoxycorticosterone, 18-hydroxycorticosterone (18-OHB) and aldosterone responses to metoclopramide 10 mg iv in the presence of a vehicle or dopamine (3 μg/kg/min) infusions, or domperidone 10 mg iv were evaluated in 10 normal males. Metoclopramide, and the peripheral dopamine antagonist, domperidone both resulted in rises in serum prolactin levels. Metoclopramide, but not domperidone, resulted in parallel rises in plasma 18-OHB and aldosterone levels. Dopamine infusion markedly inhibited prolactin, 18-OHB and aldosterone responses to the central and peripheral dopamine antagonist metoclopramide. Administration of the dopamine agonist, bromocriptine, 2.5 mg three times a day for 4 days suppressed (P < 0.01) mean 24 h plasma 18-OHB levels from 22.1 ± 2.1 to 15.8 ± 1.5 ng/dl. These results suggest that dopaminergic mechanisms modulate the secretion of 18-OHB and aldosterone. The circadian rhythm of 18-OHB secretion is not dependent on dopaminergic mechanisms.
Effect of sulpiride-induced hyperprolactinaemia on catecholamine turnover and LRH concentration in the medial basal hypothalamus of rats
Authors: Chatani Fumio , Aono Toshihiro , Koike Koji , Tasaka Keiichi , Kurachi Keiichi 
Published: December 2008

Abstract.
In order to clarify the mechanism of hyperprolactinaemic anovulation, the medial basal hypothalamic (MBH) catecholamine (CA) turnover and LRH concentration, and the serum levels and pituitary contents of gonadotrophins and prolactin (Prl) in hyperprolactinaemic female rats were examined. Hyperprolactinaemia (HPrl) was produced by oral administration of sulpiride for 10 consecutive days; each measurement made on the sulpiride-treated rats was compared with that of control dioestrus rats. Prl, LH, FSH and LRH were determined by radioimmunoassay; CA turnover, as assessed by the accumulation of CA following monoamine oxidase inhibition, was assayed by high performance liquid chromatography with electrochemical detection. Sulpiride treatment induced (1) an increase in the serum Prl and a decrease in the serum LH, (2) an increase in the pituitary FSH and LH contents, (3) an increase in the MBH LRH concentration, and (4) an increase in the MBH dopamine (DA) turnover. These results suggest that HPrl may induce anovulation by impaired LH secretion which was caused by the suppression of LRH release due to an increase in DA turnover in the MBH.
Human pituitary chronoendocrinology: repetitive stimulation with LRH/TRH at different times of the day
Authors: Pérez-López F. R. , Legido A. , Abós M. D. , Lafarga L. 
Published: December 2008

Abstract.
To determine whether human pituitary is characterized by a circadian periodicity in response to repetitive injection of hypothalamic hormones, 8 healthy subjects were challenged iv with a triple stimulation with 50 μg of LRH and 100 μg of TRH in a single bolus at 0, 90 and 180 min, receiving the first pulse of hypothalamic hormones either at 02.00 h (02.00 h test) or at 09.00 h (09.00 h test). In addition, a placebo was injected instead of LRH/TRH to evaluate the spontaneous hormonal changes during the 02.00 h test.
The LH, FSH, Prl and TSH basal levels were similar in the two phases studied. The mean LH, FSH and TSH peaks after each injection of LRH/TRH were similar among them. The mean Prl peak responses to the third pulse of LRH/TRH, in both the 02.00 h and the 09.00 h tests, were lower (P < 0.05) than those after the first pulse of LRH/TRH. Placebo did not significantly change circulating LH, FSH, Prl or TSH during nocturnal sampling. The mean LH, FSH and Prl levels after LRH/TRH during the 02.00 h test were similar to those during the 09.00 h test. The mean TSH levels 15 min after the second and third pulses of LRH/TRH during the 02.00 h test were higher (P < 0.05) than those of the 09.00 h test.
Thus, thyrotropes responsiveness to pulsatile stimulation with LRH/TRH is greater during the night than in the morning, while LH, FSH and Prl responses remain constant at the two phases studied.
TSH unresponsiveness, a case report
Authors: Aarseth Hans Petter , Haug Egil , Raknerud Nils , Frey Harald M. 
Published: December 2008

Abstract.
A patient with congenital primary hypothyroidism is presented. His thyroid gland had a normal uptake of radioiodine which was independent of endogenous or exogenous TSH, sympathetic B-receptor blockade or prostaglandin inhibition. Infusion of dibuturylcyclic AMP increased the uptake of radioiodine and stimulated release of protein bound 131I. He had no goitre even when he did not receive thyroxine, but thyroid histology showed evidence of active epithelium in the presence of adequate substitution with thyroxine. We assume that some unknown factor other than TSH stimulates part of the glandular function in this patient, without leading to adequate formation and release of thyroid hormone.
Further support for heterogeneity of insulin response and insulin sensitivity in non-obese subjects with glucose intolerance
Authors: Ratzmann K. P. , Witt S. , Schulz B. 
Published: December 2008

Abstract.
The relationship of insulin secretion and insulin sensitivity was studied in 67 age- and body weight-matched non-obese subjects, classified as having a normal glucose tolerance or glucose intolerance (50 g oral glucose load). Insulin response was studied by means of a 2 h glucose infusion. For the determination of insulin sensitivity a 1 h priming dose-constant insulin infusion technique was used. The per cent decrease of plasma glucose level at comparable steady-state insulin levels served as a measure of body sensitivity to exogenous insulin. In patients with glucose intolerance the early (ΔIRI area 0–5 min) and late (ΔIRI area 30–120 min) insulin responses to iv glucose were significantly reduced in comparison to controls. Controls and subjects with glucose intolerance showed considerable heterogeneity of insulin responses. Patients with glucose intolerance and relative insulin deficiency were not less responsive to insulin than subjects with normal glucose tolerance. There was, however, a wide variation of insulin sensitivity within the two groups. There was a weak significant inverse correlation between insulin response to glucose and insulin sensitivity for the two groups combined and for controls and subjects with glucose intolerance separately. The results demonstrate that the majority of non-obese patients with glucose intolerance and relative insulin deficiency does not exhibit a reduced responsiveness to insulin and therefore hypoinsulinaemia but not insulin resistance is the primary defect for an abnormal glucose tolerance in these group of subjects.
Hepatic extraction of insulin after carbohydrate hyperalimentation
Authors: Olsen Margrethe E. , Faber Ole K. , Binder Christian 
Published: December 2008

Abstract.
Peripheral venous plasma insulin and C-peptide concentrations during oral glucose tolerance tests were measured in 7 normal weight non-diabetic subjects before and after 7 days of sucrose hyperalimentation. This induced a deterioration of the glucose tolerance with higher levels of glucose, insulin and C-peptide.
The C-peptide to insulin molar ratio as well as the relation between incremental areas under the plasma curves of the two peptides were used as relative measures of the hepatic insulin extraction.
Both estimates of hepatic insulin extraction were unchanged by hyperalimentation, suggesting that the induced decreases in glucose tolerance and insulin receptor function are not followed by a decrease in hepatic insulin extraction as found in obese subjects with similar changes in glucose tolerance and insulin receptor function.
The renin-angiotensin system in association with hyperreninaemic hypoaldosteronism in neoplasia induced hypercalcaemia
Authors: Sowers J. R. , Barrett J. D. 
Published: December 2008

Abstract.
The renin-angiotensin system was examined in Fischer rats at 7, 11 and 14 days after Leydig cell tumour transplantation and in age matched controls. Mean arterial blood pressure (MAP), active plasma renin and serum calcium were higher (P < 0.01) in the tumour transplant rats than in the controls at 11 days after transplantation. There was a positive correlation of both active renin and MAP with serum calcium at this time. Although inactive renin levels were elevated in the tumour transplanted rats, the ratio of inactive to active renin was decreased in comparison to controls. Plasma norepinephrine, active renin and plasma angiotensin II were higher in tumour rats at 14 days. Nevertheless, basal levels of aldosterone and MAP as well as aldosterone responses to graded infusion of angiotensin II, ACTH and KCl were decreased in the tumour rats at 14 days. Moderate hypercalcaemia (day 7 and 11), induced by Leydig cell transplantation in the Fischer rat, is associated, therefore with elevated blood pressure which appears to be related, in part, to activation of the reninangiotensin system. However, severe hypercalcaemia (day 14) was associated with hypotensive hyperreninaemic hypoaldosteronism state.
Vitamin E prolongs survival and function of porcine Leydig cells in culture
Authors: Mather J. P , Saez J. M. , Dray F. , Haour F. 
Published: December 2008

Abstract.
Vitamin E (α-tocopherol) is known to be required for testicular function but its action on specific testicular cells has not yet been studied. The present study used procine Leydig cell cultures, in a hormone-supplemented medium, to study the effect of vitamin E (vit E) on Leydig cells. It was seen that the addition of vit E to the medium led to an increase in cell survival, lengthening the life span of the cultures from 3–4 days to more than a week. The Leydig cells maintained their LH/hCG receptors and responsiveness throughout this period as evidenced by an increase in testosterone (T) and prostaglandin secretion. The hCG stimulated T levels were synergistically increased in the presence of vitamin E, while basal levels of T secretion were not changed. Other secretory products of Leydig cells are prostaglandins E2 and F2α. It was found that the addition of vit E inhibited both the basal prostaglandin levels and the stimulated levels by 90%. Maximal effects on all of these parameters were seen at 10 ng/ml vit E. It is obvious that vit E plays a critical role in maintaining porcine Leydig cells in primary cultures beyond the first 3 days. This vitamin seems to be involved both in steroidogenesis and in prostaglandin production in the Leydig cells. The exact mechanism of the action of vit E these two biosynthetic pathways remains to be determined.
Impaired prolactin response to arginine infusion and insulin hypoglycaemia in chronic renal failure
Authors: Schmitz O. , Møller J. 
Published: December 2008

Abstract.
The elevated level of circulating prolactin present in the majority of uraemic patients on chronic haemodialysis is primarily due to hypothalamic pituitary dysfunction. So far this defect has been illustrated by demonstration of a blunted prolactin response to TRH and failure of l-dopa to suppress prolactin levels. In the present study two powerful prolactin and growth hormone stimuli, namely iv arginine infusion and insulin hypoglycaemia were applied in a group of uraemic patients on chronic haemodialysis and in age matched control subjects. The prolactin increments to arginine infusion (4.4 ± 1.2 ng/ml vs 17.6 ± 4.6 ng/ml, mean ± se) and to insulin hypoglycaemia (7.9 ± 1.7 ng/ml vs 31.5 ± 5.4 ng/ml) were significantly suppressed in the uraemic patients compared to the controls (P < 0.05). In contradistinction the growth hormone rise provoked by the tests were similar in the two groups.
Our results provide further insight into the hypothalamic pituitary derangement in uraemic patients and confirm the presumption of an insensitivity of the lactotrophs to stimulation in uraemic patients.
Thyroid function in goitrous subjects with thyroxine binding globulin deficiency
Authors: Callan F. P. , Duffy M.J. , Duffy G.J. , Farrell R.J. , McKenna T.J. 
Published: December 2008

Abstract.
The co-existence of thyroxine binding globulin (TBG) deficiency and euthyroid goitre in the same family raised the possibility that the disorders might be related. However, although both disorders co-existed in some members of the family, other members had either but not both conditions. These observations exclude the possibility that goitre development was solely due to alterations in thyroid activity brought about by TBG deficiency. It is possible, however, that the defect in protein binding might have enhanced goitre development in predisposed individuals as the two largest goitres occurred in TBG deficient subjects. Of the conventional parameters used to assess thyroid hormone levels in TBG deficient subjects, only the free triiodothyronine index consistently reflected the euthyroid status of these patients as established by clinical examination and TSH levels.
Recovery of thyroid function with a decreased titre of antimicrosomal antibody in a hypothyroid man with Hashimoto's thyroiditis
Authors: Yamamoto Makiko , Kaise Kazuro , Kitaoka Hirofumi , Yoshida Katsumi , Kaise Nobuko , Fukazawa Hiroshi , Sakurada Toshiro , Saito Shintaro , Yoshinaga Kaoru 
Published: December 2008

Abstract.
A 36 year old man with a diffuse goitre, signs of mild hypothyroidism, strikingly low levels of T4 (0.9 μg/dl) and T3 (24 ng/dl), elevated TSH (140 μU/ml) and elevated microsomal haemagglutination antibody (MCHA, 1:409 600), subsequently became non-goitrous and euthyroid with a decreased titre of antimicrosomal antibody without any medication. At the time of surgical biopsy, serum levels of T4 and T3 had risen to the normal range (4.6 μg/dl and 73 ng/dl, respectively), serum TSH had decreased to 30 μU/ml and the titre of MCHA to 1:25 600. Thyroid specimens showed Hashimoto's thyroiditis. The activity of thyroid peroxidase (TPO) was normal. The latest examination, 1 year and 3 months after initial evaluation, showed that the patient remained euthyroid with no goitre, that serum thyroid hormones were within the normal range (T4 7.7 μg/dl and T3 97 ng/dl), and that TSH was not detectable. The titre of MCHA decreased strikingly to 1:400.
HLA antigens in a family with both parents and several siblings affected by Graves' disease
Authors: Castañer M. Fernández , Potau M. Angel , Reus J. Cabrer , Ercilla M. G. 
Published: December 2008

Abstract.
A family with autoimmune thyroid disease is described. Four members had Graves' disease and 3 had diffuse goitres. Both parents (second cousins) carry the HLA haplotype: HLA Aw24, Bw39(w6), Cw-, DR3, MT2. Only females with this haplotype show thyroid symptoms. These findings emphasize the involvement of HLA linked genes in susceptibility to Graves' disease.
The effect of hyperglucagonaemia on blood glucose concentrations and on insulin requirements during fasting in insulin dependent diabetes mellitus
Authors: Clarke W. L. , Melton T. W. , Bright G. M. 
Published: December 2008

Abstract.
The effect of sustained hyperglucagonaemia on blood glucose concentrations and on insulin requirements was evaluated in 6 fasting insulin dependent diabetic subjects whose blood glucose concentrations were being controlled with a closed loop insulin infusion system. Subjects were iv infused initially with either saline or glucagon and subsequently with the other infusate. All determinations were performed following the period during which transient increases in glucagon stimulated glucose production have been reported to occur.
Plasma glucagon concentrations were significantly higher during the glucagon study period (491±65 vs 70±13 pg/ml ± sd, P<0.001) as were blood glucose concentrations(104 ± 2 vs 84 ± 7 mg/ml ± sd, P<0.001) and insulin requirements (3.5 to 36.5 vs 0 to 2.3 mU/kg/h, P<0.05). Sustained hyperglucagonaemia continues to have an effect on glucose homeostasis for at least 2 h following the initiation of a continuous infusion.
Glucose- and arginine-induced insulin and glucagon responses from the isolated perfused pancreas of the BB-Wistar diabetic rat. Evidence for selective impairment of glucose regulation
Authors: Grill V. , Herberg L. 
Published: December 2008

Abstract.
To investigate whether preferential responsiveness of residual B-cells is a feature of a diabetic state we compared insulin-releasing effects of glucose and arginine in perfused pancreases from moderately diabetic BB-Wistar rats. BB-rats were hyperglycaemic and insulin-dependent but possessed some insulin reserves (6 per cent of pancreatic content of control Wistar rats). Glucose (27.7 mm) failed to release insulin from diabetic pancreases while, conversely, arginine (8 mm) evoked a several-fold increase in insulin secretion. Ratios between responses from diabetic and normal pancreases were 0.01 and 0.29, respectively, when glucose or arginine were used as stimuli. This difference was significant (P < 0.05, Wilcoxon test). Glucose furthermore failed to exert a time-dependent (= priming) effect on arginine induced insulin secretion in the diabetic animals. Also A-cell responsiveness to glucose (acute and priming effects) were lost in BB-rats. It is concluded that selective loss of glucose effects on B- and A-cell secretion are associated with the diabetic state of the BB-Wistar rats.
Enhancement of corticosterone release by repeated injections of ACTH in the dexamethasone pre-treated rat
Authors: Murakami Noboru , Takahashi Kiyohisa 
Published: December 2008

Abstract.
To examine the possibility that pulsatile secretion of adrenocorticotrophic hormone (ACTH) enhances the responsiveness of the adrenal, the blood corticosterone response to repeated injections of ACTH was determined in the dexamethasone-nembutal pre-treated rat. Treatment with dexamethasone (100 μg/100 g body weight) at 13.00 h for 2 days decreased corticosterone levels and completely abolished these daily variations in both the blood and adrenal. Under these conditions, four or five successive iv injections of 0.2 or 2 mIU ACTH were given at ½ or 1 h intervals. Blood samples were taken immediately before and at frequent intervals after injection. A significant increase of blood corticosterone levels was observed 10 min after the second injection of 0.2 mIU ACTH. Further increases in blood corticosterone levels were observed after the subsequent injections. In addition, repeated injections of 2 mIU ACTH augmented the responsiveness of the adrenal to ACTH. The second or the third injections of 2 mIU ACTH produced a greater increase in adrenal corticosterone content than did the first ACTH injection.
These results suggest that when ACTH acts on the adrenal gland in a pulsatile fashion, the steroidogenic response of the adrenal to ACTH increases markedly.
Induction of puberty by prolonged pulsatile LRH administration
Authors: Delemarre-van de Waal Henriette A. , Schoemaker J. 
Published: December 2008

Abstract.
Pubertal maturation was induced in a 17.7 year old hypogonadotrophic boy by pulsatile LRH treatment. LRH was administered in three periods. During period one 20 μg LRH pulses were given iv 16 times per day for 10 weeks; during period two 2 μg LRH pulses iv 16 times per day for 12 weeks. During period three 2 μg LRH pulses 16 times per day were given sc for 13 weeks. Treatment was interrupted for 6 weeks between period one and two.
Rapid initiation of pubertal maturation was evidenced by an increase of penile length and testicular volume as well as by growth of pubic hair. After 21 weeks of treatment spermatozoa were observed in the ejaculate. Gonadotrophin levels increased from prepubertal values into the supranormal range in the beginning of period one, spontaneously declining to normal adult levels. A rapid increment of testicular volume during period one was also evidence for overstimulation.
During period two gonadotrophin levels were in the normal range.
Testosterone levels were normal during period one and two albeit higher during period one. We conclude that 1) pulsatile LRH treatment with 2 μg per pulse iv 16 times per day is an adequate and feasible way to induce puberty in hypogonadotrophic males with an intact pituitary. 2) Under pulsatile LRH treatment spermatogenesis takes place more rapidly than during normal puberty. 3) Testicular hormones exert a negative feedback action at the pituitary in the LRH treated hypogonadotrophic male. 4) The supranormal levels of LH and FSH during the first weeks of treatment may be caused by a delayed reaction of the testicles to gonadotrophin stimulation rather than to an overdose of LRH. 5) No evidence was found of a direct inhibitory action of LRH on testicular function.