bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibition of bone resorption and lysosomal enzyme release from calvarial bones cultured for 24 hours: synergism between cyclic AMP analogues and phosphodiesterase inhibitors
Authors: Lerner Ulf 
Published: December 2008

Abstract.
The effect of N6-monobutyryl adenosine 3′,5′-cyclic monophosphate (mbcAMP), N6,O2′-dibutyryl adenosine 3′,5′-cyclic monophosphate (dbcAMP), 8-bromo adenosine 3′,5′-cyclic monophosphate (8-brcAMP), adenosine 3′,5′-cyclic monophosphate (cAMP) and two phosphodiesterase (PDE) inhibitors, theophylline and 3-isobutyl-methylxanthine (IBMX) on bone resorption was studied in an organ culture system for 24 h using half calvaria from 6–7 day old mice. The parameters studied were: the release of calcium (Ca2+), inorganic phosphate (Pi), β-glucuronidase, β-galactosidase, lactate dehydrogenase (LDH), and 45Ca from the bones to the medium. With dbcAMP, in concentrations between 5 × 10−5m and 2.5 × 10−4m, and with 8-brcAMP, in concentrations between 10−5m and 5 × 10−5m, a dose-dependent inhibitory effect on the spontaneous release of 45Ca from the explants was found. IBMX and theophylline in doses of 10−3m and 2.5 × 10−3m, respectively, inhibited the spontaneous mobilization of 45Ca, while hypoxanthine, which lacks PDE inhibitory capacity, did not affect the release of 45Ca. When cAMP or its analogues were combined with IBMX, a potentiated inhibitory effect on mineral mobilization and lysosomal enzyme release was seen. In contrast, adenosine 5′-monophosphate, 8-bromo adenosine 5′-monophosphate and sodium butyrate did not reduce the release of 45Ca when applied alone or combined with IBMX. PDE inhibitors combined with parathyroid hormone (PTH) resulted in a reduction of the PTH-stimulated bone resorption. The results provide further evidence that cAMP is not a mediator of the early stage of PTH-induced bone resorption, but on the contrary inhibits mineral mobilization and lysosomal enzyme release from cultured bones.
Prolactin, LH, FSH, GH and cortisol response to surgery and the effect of epidural analgesia
Authors: Hagen Claus , Brandt Mogens R. , Kehlet Henrik 
Published: December 2008

Abstract.
The prolactin, LH, FSH, growth hormone and cortisol responses to surgical stress were studied in female patients receiving halothane (general) anaesthesia or epidural analgesia. Plasma cortisol, prolactin, and growth hormone concentrations increased during surgery, and post-operatively in patients operated under general anaesthesia, but not in patients operated during epidural analgesia. Gonadotrophin concentrations were unchanged in the general anaesthesia group until 9 h after stimulation when levels decreased slightly. In contrast plasma gonadotrophin levels decreased immediately after the administration of epidural analgesia and during the following 9 h. It is concluded that neurogenic blockade inhibits the anterior pituitary response to surgial stress.
Somatomedin A levels in serum from healthy children and from children with growth hormone deficiency or delayed puberty
Authors: Hall Kerstin , Enberg Gösta , Ritzén Martin , Svan Håkan , Fryklund Linda , Takano Kazue 
Published: December 2008

Abstract.
Serum somatomedin A (SMA) has been determined in healthy children (n = 188) in relation to age using both a radioimmunoassay and a radioreceptor assay. The SMA levels, only 50% of adult values at birth, rise gradually with age and reach adult levels at 10 years of age. There is a significant correlation (r = 0.46, P < 0.001) between SMA determined by the two methods throughout childhood except during puberty. Immunoreactive SMA shows a marked pubertal rise in values with a peak 2 years earlier for girls than boys, which is not observed by the radioreceptor assay technique. In boys with delayed puberty the increase in immunoreactive SMA is seen first when the testes reach a size of 5 ml. Children with growth hormone deficiency (n = 30) had significantly lower levels of SMA than healthy age-matched controls. Immunoreactive SMA gives a better separation of these groups than the values obtained by radioreceptor assay.
Effect of acute hypercalcaemia on glucose tolerance and insulin release in human beings
Authors: Gedik O. , Akalin S. , Koray Zehra 
Published: December 2008

Abstract.
Insulin secretion in response to an oral glucose challenge during acute hypercalcaemia was studied. Oral glucose tolerance tests (OGTT) were performed in 12 non-diabetic, non-obese human volunteers, aged 20–28 years. Blood samples were collected for calcium, glucose and insulin determination. The next day the same volunteers received a 4 h infusion of calcium gluconate (15 mg/kg/4 h) and were administered glucose 1 h after starting the infusion. Serum calcium, glucose and insulin concentrations were measured again.
Infusion of calcium gluconate resulted in an increase in serum calcium concentration of 5 mg/100 ml over 4 h. During these infusions no significant changes in glucose concentrations were noted. On the other hand, the total mean insulin concentration, expressed as the area under the 3 h glucose tolerance curve, and the insulin peak at 30 min were significantly increased during hypercalcaemia (P < 0.001).
These data indicate that acute hypercalcaemia does not affect carbohydrate tolerance but increases insulin secretion in human beings.
The effect of cyproterone acetate on serum lipids in normal men
Authors: Damgaard-Pedersen Finn , Føgh Marie 
Published: December 2008

Abstract.
In a male anti-fertility study 7 volunteers received the anti-androgen cyproterone acetate (5 or 10 mg daily) orally in a paired study. A significant reduction in serum-cholesterol and LDL-cholesterol, and a significant increase in the intravenous-fat-tolerance-test (IVFTT) was observed. Thus low doses of cyproterone acetate reduced the serum testosterone concentration and some of the atherosclerotic risk factors.
Inhibition of vasopressin secretion by a met-enkephalin (FK 33-824) in humans
Authors: Brownell Judith , del Pozo Emilio , Donatsch Peter 
Published: December 2008

Abstract.
To investigate the effect of a met-enkephalin analogue, FK 33-824, on renal handling of water, 8 subjects were given 0.5 mg im of the drug or placebo in a cross-over study. In a second trial under the same testing conditions, a 4 mg dose of naloxone iv was given to 6 subjects immediately preceding 0.5 mg FK 33-824 im. Urine and blood samples were collected at hourly intervals. Urinary vasopressin (AVP) and plasma prolactin (Prl) were assayed, and free water clearance (FWC) was calculated. Following the same protocol, a further 6 subjects received 5 IU of lysine vasopressin im 5 min preceding administration of FK 33-824.
FK 33-824 significantly (P < 0.001) increased Prl and FWC and reduced urinary concentrations of AVP (P < 0.01). Naloxone pre-treatment failed to modify significantly the latter two responses, while Prl stimulation was inhibited. Lysine vasopressin pre-treatment abolished the effect of FK 33-824 on FWC while the stimulating action on Prl was preserved.
These results indicate that in humans FK 33-824 reduces AVP secretion and that this effect is not mediated by naloxone sensitive opiate receptors.
The effect of heat exposure on blood serum levels of anterior pituitary hormones in calves, heifers and bulls
Authors: Schams D. , Stephan E. , Hooley R. D. 
Published: December 2008

Abstract.
In four experiments male and female calves, heifers and bulls were housed in a climate chamber and exposed to two weeks of hot environmental conditions (30–35°C and 60% relative humidity (RH) during the day; 25°C and 60–70% RH during the night). The animals were subjected to milder conditions (15–18°C and 70% during the day; 12–15°C and 70% during the night) during the two week period preceding and the two weeks following heat exposure. Serum prolactin increased significantly (P < 0.01) when ambient temperature was increased and decreased after reduction of temperature. No changes could be observed for GH, TSH, LH and FSH. There was a significant (P < 0.01) sex difference in GH levels (males < females) in pre-pubertal calves but this difference was not apparent in older animals.
Effect of prolactin inhibition under heat exposure on water intake and excretion of urine, sodium and potassium in bulls
Authors: Schams D. , Stephan E. , Hooley R. D. 
Published: December 2008

Abstract.
Six Holstein bulls were housed in a climate-chamber under constant light regimen and after two weeks of preconditioning at 15°C, 60% relative humidity RH (day) and 12°C, 60% RH (night) were subjected to two weeks of heat exposure. This involved one week at 30°C and 60% RH (day) and 25°C and 60% RH (night) and a further week at 35°C, 60% RH (day) and 30°C, 60% RH (night). Three bulls were untreated (group I) and 3 bulls were treated (group II) just before and during heat exposure with a prolactin inhibitor to study the possible physiological role of prolactin on the regulation of water, potassium and sodium.
Serum prolactin levels increased significantly (P < 0.01) in group I from the control value of 6 ng/ml to 33 and 44 ng/ml when the ambient temperature was increased (weeks 3 and 4) and then decreased to 21 and 12 ng/ml after reduction in temperature during weeks 5 and 6, respectively.
For group II prolactin values decreased under the treatment with the prolactin inhibitor to 0.5 ng/ml and remained at this level throughout the experiment. GH levels were unaffected by heat treatment or by treatment with prolactin inhibitor. There were no differences between groups I and II in respiratory rate, pulse rate and rectal temperature. Water intake increased in both groups under heat exposure but decreased significantly afterwards only in group II. Differences in urinary excretion volume and blood serum osmolality were not significant. Urinary potassium and sodium excretion were unchanged in group II but increased with heat exposure in group I. During heat exposure 2 bulls of group II lost weight despite maintaining food intake.
Role of the renin-angiotensin system in the adaptation of aldosterone biosynthesis to sodium restriction in the rat
Authors: Tarján Eva , Spät András , Balla Tamás , Székely Annamária 
Published: December 2008

Abstract.
The purpose of the present study was to evaluate the role of the renin-angiotensin system in the secretion of aldosterone during restriction of dietary sodium intake. Rats were kept on control or low-sodium diet for one week. On the 7th morning of diet osmotic minipumps filled with the angiotensin converting enzyme inhibitor (CEI) SQ 20,881, or empty pumps, were implanted subcutaneously (sc). The rats were sacrificed 23 h later. Peripheral blood was analyzed for hormones and electrolytes. Adrenal capsular tissue (z. glomerulosa) was incubated for the determination of the conversion of [3H]corticosterone to [3H]aldosterone.
Sodium depletion had no effect on plasma sodium, but it increased potassium concentration. Infusion of CEI had no significant effect on plasma electrolytes. Plasma renin activity was increased both by sodium depletion and CEI. The mean serum aldosterone level was twelve times higher in sodium depleted animals than in controls. Aldosterone level was reduced by about 60 per cent in CEI-infused animals both on control and low-sodium diet. The conversion of corticosterone to aldosterone was significantly stimulated by sodium deprivation. This effect was also inhibited by the CEI SQ 20,881.
Ontogeny of pituitary gonadotrophin hormone activity and of testicular responsiveness to gonadotrophins in foetal rabbit
Authors: Veyssiere G. , Berger M. , Jean-Faucher Ch. , de Turckheim M. , Jean Cl. 
Published: December 2008

Abstract.
Synthesis and secretion of T and DHT by 18, 19 and 20 day old foetal rabbit testes were measured (RIA) in an organ culture system (M199). It was demonstrated that synthesis and secretion in vitro of T and DHT were greater at 19 and 20 days than at 18 days. The T and DHT production could be stimulated by ovine LH at 19 and 20 days but not at 18 days. The pituitaries of 19 and 20 day old male and female foetuses (but not those of foetuses aged 18 days) stimulate synthesis and secretion of T by 20 day old testis. A gonadotrophic factor, active on testicular T production, is present in the pituitary gland of 19 day old foetuses of both sexes.
These findings indicate that the testicular responsiveness to LH and to the pituitary appears concomitantly with the pituitary gonadotrophic activity, between 19 and 20 days, just prior to the beginning of male sexual differentiation (20–25 days).
The value of an intravenous TRH test for the diagnosis of tumoural prolactinaemia
Authors: Assies J. , Schellekens A. P. M. , Touber J. L. 
Published: December 2008

Abstract.
The plasma Prl response to 200 μg TRH iv was evaluated in 6 hyperprolactinaemic women without radiological evidence of a pituitary tumour (group I), in 15 hyperprolactinaemic women with dubious (group II) and in 17 normo- or hyperprolactinaemic women with clear (group III) radiological abnormalities, in 18 normoor hyperprolactinaemic men with clear radiological abnormalities (group IV), and in 4 women and 3 men with hyperprolactinaemia and sellar destruction who had been treated in the past for pituitary adenoma (group V). The responses were compared with those obtained in a control group of 83 (42 women, 41 men) normoprolactinaemic healthy individuals. The Prl response was defined as a ratio (R2): the 20 min value minus the 0 min value, divided by the 0 min value.
The median R2 values were: female controls 5.1, male controls 3.1, group I 0.1, group II 0.2, group III 0.3, group IV 0.55, group V females 0.45 and males 0.
It is concluded that 1) subjects suspected of harbouring a microprolactinoma (groups I and II) demonstrate absent or attenuated responses similar to those found in patients with definite prolactinomas and 2) a value of plasma Prl 20 min after 200 μg TRH iv greater than 3.5 times the basal level (R2 > 2.5) rules out the presence of a prolactinoma.
The clinical and biochemical features in 26 patients with prolactinoma before and after transsphenoidal microresection
Authors: Samaan Naguib A. , Elhaj George E. , Leavens Milam E. , Franklin Robert R. 
Published: December 2008

Abstract.
Twenty-six women, 16 to 40 years of age, with amenorrhoea with or without galactorrhoea and abnormal pituitary fossa tomogram were studied before and after transsphenoidal resection of their pituitary adenomas. The immunoreactive serum prolactin (Prl) was abnormally high both before and after intravenous (iv) administration of thyrotrophin-releasing hormone (TRH) but the rise was blunted. The serum Prl level returned to normal post-operatively in 20 patients, but the subnormal rise after TRH persisted in 23 patients. The basal serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were normal before and after surgery. The peak serum level of LH after administration of the luteinizing hormone-releasing hormone (LRH) was normal but the peak FSH was significantly high before surgery (P < 0.001) and returned to normal post-operatively. Plasma oestradiol (Oe2) was significantly low compared to that after surgery (P < 0.001). Plasma testosterone (T) was significantly higher before surgery than that found in normal women (P < 0.001) and the level fell post-operatively. Plasma androstenedione (A) was higher before surgery than found in normals, but the difference was not significant (P < 0.2).
Post-operatively, 23 patients regained their normal menses. Three of these 23 patients continued to have high serum Prl but the serum Oe2 returned to normal. Sixteen of 20 patients who desired pregnancy became pregnant post-operatively. None of the patients required hormonal replacement after surgery.
These data indicate that the measurement of LH or FSH at basal and after LRH stimulation, may not be of significant prognostic importance compared with serum Prl and plasma Oe2. Regular menses and pregnancy can occur in some patients in spite of moderately high serum Prl but normal plasma Oe2 levels.
Surgical resection of prolactinoma has low morbidity with a high incidence of success resulting in return of normal menses and fertility. The persistent subnormal rise of Prl after TRH post-operatively in the majority of the patients suggests that long-term follow-up for evidence of recurrence is indicated.
Precocious and delayed puberty. Studies of FSH and LH production and metabolism
Authors: Raiti Salvatore , Maclaren Noel K. , Akesode F. A. 
Published: December 2008

Abstract.
We measured the production rates and metabolic clearance, disappearance and excretion rates of FSH and LH as well as plasma testosterone and Δ4androstenedione in males with precocious and delayed puberty. In precocious puberty, we found modestly elevated FSH production early in puberty, reaching adult levels by midpuberty and remaining constant thereafter. LH production was low early in puberty, reached high levels at midpuberty and then fell. The plasma testosterone concentrations paralleled the changes in LH. This suggests that moderate FSH production is achieved by early puberty and adult levels are reached by midpuberty. On the other hand LH production is low early in puberty, reaches high levels by midpuberty and then falls again towards the end of puberty.
Constitutional delay in sexual development probably consists of several syndromes due either to a delay in LH production or to FSH production or to both. One patient with hypogonadotrophic hypogonadism was also studied. He showed relatively normal LH production but very low FSH production.
Urinary excretion of catecholamines in healthy subjects in relation to body growth
Authors: Parra A. , del Angel A. Ramírez , Cervantes C. , Sánchez M. 
Published: December 2008

Abstract.
The daily urinary excretion of dopamine (DA), noradrenaline (NA) and adrenaline (A) was investigated in 43 clinically healthy males and 37 females, aged 13 days to 37.5 years. There was a progressive increase in the daily output of each catecholamine (μg/24 h) with increasing age (P < 0.025 to < 0.001), and the opposite was seen when values were expressed as μg/g creatinine (P < 0.05 to < 0.025). However, when values were expressed as μg/m2/24 h no significant differences were disclosed among the different age groups, except for a transient rise in DA excretion in the group 1.0–4.9 years. A significant linear correlation was observed between chronological age and urinary DA (r = 0.814, P < 0.05), NA (r = 0.837, P < 0.05) and A (r = 0.839, P < 0.05), and also between body weight and each one of the catecholamines (DA: r = 0.731, P < 0.05; NA: r = 0.839, P < 0.05; A: r = 0.720, P < 0.05). However, a quadratic correlation existed between height and DA (r = 0.759, P < 0.05), NA (r = 0.853, P < 0.05) and A (r = 0.814, P < 0.05). Each one of these models could explain up to 73% of the observed variability. It is suggested that: a) the most convenient form to express the daily urinary excretion of catecholamines is as μg/m2/24 h; b) the excretion of these compounds increased at a faster rate approximately after 130.0—135.0 cm of height; c) this height-related greater increase in the output of catecholamines occurs simultaneously with previously reported increases in haemoglobin and haematocrit and significant changes in plasma concentrations of thyroid hormones; d) although the mechanisms involved in these changes remain to be clarified, it is interesting to note that they occur at a time when oxygen requirements are greater consecutive to the rapid increase of lean body tissues.
Thyrotroph cell adenoma of the human pituitary gland associated with primary hypothyroidism: clinical and morphological features
Authors: Katz Michael S. , Gregerman Robert I. , Horvath Eva , Kovacs Kalman , Ezrin Calvin 
Published: December 2008

Abstract.
The morphological features of a pituitary adenoma resected from a 39-year-old woman with hypothyroidism have been investigated. Hypothyroidism followed radioactive iodine treatment of pre-existing hyperthyroidism, presumably Graves' disease. Blood TSH was low during a euthyroid interval and was elevated above normal with the onset of hypothyroidism. The presence of a small amount of TSH was demonstrated in the tumour by radioimmunoassay. By conventional histology the tumour was a chromophobe adenoma. Some fine secretory granules stained with aldehyde thionin but were negative with PAS and contained no immunoreactive TSH. By light and electron microscopy, the tumour cells differed from thyroid deficiency cells. They were small and angular, containing numerous microtubules and small spherical secretory granules, oriented mainly along the plasma membranes. The tumour was considered to represent a thyrotroph cell adenoma, arising from protracted overstimulation secondary to chronic thyroid hormone deficiency.
Biosynthesis of 16α,17α-epoxy-oestratrienol in rat liver microsomes
Authors: Siekmann L. , Thull P. , Breuer H. 
Published: December 2008

Abstract.
After incubation of 1,3,5(10),16-oestratetraenol, a 16-dehydrosteroid, with rat liver microsomes, 16α,17α-epoxy-oestratrienol was isolated as metabolite. The compound was detected by the use of mass fragmentography after purification of the incubation extract by thin-layer chromatography. Since the epoxide is rapidly hydrolysed by a hepatic epoxide hydratase, only very small concentrations of this metabolite were present in the incubation extract. When styrene oxide was added to the incubation mixture as inhibitor of the epoxide hydratase, the yield of the steroid epoxide increased considerably. Final identification of the oestrogen epoxide was performed by recording mass spectra and by comparison with authentic reference material.
Biosynthesis of 16α,17α-epoxy-4-androsten-3-one in rat liver microsomes
Authors: Disse B. , Siekmann L. , Breuer H. 
Published: December 2008

Abstract.
4,16-Androstadien-3-one was incubated with the microsomal fraction of male rat liver in the presence of a NADPH generating system and oxygen. The metabolites formed were extracted from the incubation medium and purified by thin-layer chromatography (tic). Final identification was performed by combined gas liquid chromatography-mass spectrometry. Incubation of 4,16-androstadien-3-one resulted in the formation of a non-polar metabolite which proved to be 16α,17α-epoxy-4-androsten-3-one. This epoxide is a shortlived intermediate which is rapidly hydrolysed by the microsomal epoxide hydratase to 16β,17α-dihydroxy-4-androsten-3-one. In order to increase the amounts of epoxide in the incubation mixtures, styrene oxide which is a potent inhibitor of the epoxide hydratase was added. Under these conditions, up to 8% of the 16-dehydro-steroid incubated was transferred to the 16α,17α-epoxy-compound.