bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extracellular cyclic AMP levels in osteomalacia
Authors: de Castro Jose A. Sisson , Tucci Joseph R. 
Published: December 2008

Abstract.
Plasma and urinary cyclic AMP were measured in a 62-year-old man with severe osteomalacia due to a gluten-induced enteropathy. Before therapy, plasma cyclic AMP was normal and both urinary and nephrogenous cyclic AMP were markedly increased. A calcium infusion acutely diminished the elevated iPTH and urinary cyclic AMP levels. Following a bolus infusion of PTE, there was no phosphaturia despite a somewhat exaggerated increase in cyclic AMP excretion. With appropriate therapy, serum calcium, phosphorus, alkaline phosphatase, iPTH and 25-OHD3 and urinary and nephrogenous cyclic AMP gradually returned to normal. The response to PTE infusion after normalization of serum electrolytes, iPTH, and 25-OHD3 levels was similar to that seen before therapy.
These results demonstrate that non-azotaemic malabsorptive osteomalacia is associated with elevations in urinary and nephrogenous cyclic AMP which gradually fall to normal with therapy. In contrast to studies in the vitamin D deficient rat, the maximal urinary cyclic AMP response to PTE is not diminished in the human with malabsorptive osteomalacia. The lack of a phosphaturic response to PTE depite a normal increase in urinary cyclic AMP excretion, as seen in our patient, is similar to that described in some patients with pseudohypoparathyroidism, suggesting that the response is not specific for the latter disorder. Finally, the data suggest that endogenous PTH does not modulate its renal receptors, at least in terms of cyclic AMP generation.
Plasma growth hormone and prolactin responses to TRH and arginine given before and during bromocriptine therapy to patients with acromegaly
Authors: Hanew Kunihiko , Sasaki Atsushi , Mouri Toraichi , Yoshinaga Kaoru 
Published: December 2008

Abstract.
The chronic effects of bromocriptine (CB-154) administration on pituitary somatotrophs and lactotrophs were investigated in 9 patients with acromegaly. Following therapy with CB-154 for 3 to 20 weeks, 6 of 9 cases showed a normalization of plasma GH (below 5 ng/ml) and a clinical improvement. These cases were termed 'CB-154-responders'. Plasma GH responses to TRH were observed in all cases of'CB-154-responders' before the therapy and were significantly suppressed during CB-154 therapy, although the response patterns expressed in logarithms were retained. When TRH was administered in 3 cases of acromegaly after acute administration of CB-154 and before chronic CB-154 therapy, the peak plasma GH responses were between those responses seen before and during CB-154 therapy. After iv infusion of arginine, 5 cases of 'CB-154-responders' showed an increase in plasma GH levels. These responses were also significantly suppressed during CB-154 therapy, while the response patterns were also preserved.
In these same patients, basal plasma prolactin was consistently suppressed to low levels (mean ± sem: 3.4 ± 0.9 ng/ml) in all 9 cases during CB-154 therapy and plasma prolactin responses to TRH almost disappeared after either acute or chronic administration of CB-154.
These findings demonstrate: 1) chronic CB-154 therapy in acromegalic patients gradually reduces the activity of the somatotrophs to synthesize and to release GH while it causes a rapid and marked suppression of lactotrophs; 2) the sites of action to CB-154 on the somatotrophs may be different from those to TRH and arginine (possibly GH-RF),while CB-154 and TRH appear to have a close relationship in regard to sites of action on the lactotrophs
Prolactin responses to histamine H2 receptor antagonists
Authors: Sharpe P. C. , Melvin M. A. , Mills Jane G. , Burland W. L. , Groom G. V. 
Published: December 2008

Abstract.
We have compared the effects of cimetidine and SK&F 92994, a new more potent histamine H2 receptor antagonist, on serum prolactin, and also assessed the effect of the H2 receptor agonist impromidine on the response to cimetidine. As previously reported, cimetidine 200 mg given as an iv bolus dose produced a marked rise in serum prolactin, but 50 mg and 200 mg of SK&F 92994 given by the same route had no effect. Iv infusion of impromidine 10 μg kg−1h−1 failed to modify the prolactin response to cimetidine. It is concluded that the rise in serum prolactin following iv administration of cimetidine may be due to a specific property of cimetidine. An effect mediated via histaminergic pathways within the central nervous system, although less likely, cannot be excluded.
Effects of glucocorticosteroids on prolactin and growth hormone production and characterization of the intracellular hormone receptors in rat pituitary tumour cells
Authors: Naess Oddvar , Haug Egil , Gautvik Kaare 
Published: December 2008

Abstract.
The effect of corticosterone and dexamethasone on the production of growth hormone and prolactin was studied in rat pituitary tumour cells (GH3-cells) in culture. Corticosterone and dexamethasone caused a dose-dependent stimulation of growth hormone synthesis, and the highest concentration (10−6 mol/l) increased growth hormone levels to 250% of controls. This concentration, however, decreased prolactin synthesis to 25% of the control values.
The cytosol fractions from monolayer cultures as well as from tumours of GH3-cells were found to possess receptor molecules for glucocorticoid hormones, having a sedimentation constant close to 8 S in a salt-free buffer and 4 S in the presence of 0.5 mol/l KCL. Isoelectric point of the receptor was 5.8. Scatchard analysis showed one single class of binding sites with high affinity (Kd 2.1 ± 0.4 (sd × 10−9 mol/l). Studies on the steroid specificity revealed that dexamethasone had the highest affinity for the receptor. Corticosterone, cortisol and progesterone had also high affinity, whereas testosterone and oestradiol-17β had no significant affinity for the receptors. After in vivo administration of [3H]dexamethasone to GH3 tumour-bearing rats, radioactivity could be extracted from purified nuclei bound to 4 S macromolecules.
The presence of receptors for glucocorticosteroid hormones in the GH3-cells, suggests that these hormones may alter growth hormone and prolactin production at the anterior pituitary level.
Long-term variability in serum thyroglobulin and thyroid related hormones in healthy subjects
Authors: Feldt-Rasmussen U. , Petersen P. Hyltoft , Blaabjerg O. , Hørder M. 
Published: December 2008

Abstract.
From 5 young males and 5 young females blood was drawn under highly standardized conditions at 6 to 10 occasions during 4 months. The serum constituents thyroglobulin, thyroxine, triiodothyronine, T3-uptake test, TBG and TSH were determined, and four indices were calculated.
The biological intra-individual coefficients of variation were below 0.14 for thyroglobulin, and the inter-individual coefficients of variation ranged from zero for T3-uptake test to 0.35 for thyroglobulin.
All results were within the generally accepted reference ranges for normals. Within these ranges the calculations of indices for free thyroxine and triidothyronine according to T3-uptake test and TBG, did not significantly reduce the coefficients of variation for these serum constituents.
Thyroglobulin concentrations did not correlate to any of the measured or calculated constituents. The knowledge of these intra- and inter-individual variations of serum thyroglobulin in healthy persons is of importance for the interpretation of variations found in patients.
Decreased testicular response to acute LH-stimulation and increased intratesticular concentration of oestradiol-17β in the abdominal testes in cryptorchid rats
Authors: Damber Jan-Erik , Bergh Anders 
Published: December 2008

Abstract.
Rats were made cryptorchid, bi- or unilaterally, by cutting gubernaculum testis at birth. At 100 days of age the basal plasma testosterone concentration was smaller in bilateral cryptorchid animals as compared to unilateral cryptorchid and control rats. After acute LH-stimulation plasma testosterone concentration increased in all rats, where the highest concentrations were found in the control group. The amount of testosterone in the testis after a 30 min LH-stimulation was lower in both kinds of cryptorchid testes but higher in the scrotal testis of the unilateral cryptorchid rats, all as compared to control testis. This decreased effect of LH observed in cryptorchid animals indicates an impaired Leydig cell function in cryptorchid testis. The results also show a compensatory hyperfunction of Leydig cells in the scrotal testes of unilateral cryptorchid rats. It was also found that the intratesticular concentration of oestradiol-17β was three-fold increased in unilateral cryptorchid testes and even more in bilateral cryptorchid ones.
Pituitary hormone secretion after inhibition of L-aromatic amino acid decarboxylase activity in man
Authors: Delitala G. , Devilla L. , Pende A. 
Published: December 2008

Abstract.
The effect of acute administration of 200 mg benserazide, an L-aromatic amino acid decarboxylase inhibitor, on pituitary hormone secretion in humans was studied. Benserazide induced in all subjects a quick and marked increment of serum prolactin (Prl) and TSH levels: at 180 min TSH and Prl levels were still significantly higher than the baseline values. Women with normal menstrual cycles showed a Prl response to benserazide which was significantly greater than that observed in post-menopausal women and men. In another experiment six normal men received 10 mg of domperidone, a peripheral dopamine receptor blocker. The hormonal changes induced by domperidone were comparable to those obtained with benserazide.
Since domperidone and benserazide are thought not to cross the blood-brain barrier, these results suggest that dopamine regulates Prl and TSH secretion through extra blood-brain barrier structures.
Alteration of thyroid function in the early stage of subacute thyroiditis
Authors: Madeddu G. , Langer M. , Costanza C. , Casu A. R. , Arras M. L. , Campus S. 
Published: December 2008

Abstract.
Measurement of serum triiodothyronine (T3), thyroxine (T4), free triiodothyronine (FT3), free thyroxine (FT4), thyroxine-binding-globulin (TGB), antithyroglobulin antibodies (anti-hTg), thyroid 131I uptake and scanning was performed on 12 patients during the early phase of subacute thyroiditis. Serum thyrotropin (TSH) was measured during baseline conditions and following administration of synthetic thyrotropin-releasing-hormone (TRH). The stimulation with exogenous TSH was performed on 7 subjects. 131I uptake was depressed in all patients including those with solitary nodules. Free and total hormone concentrations were elevated in the three cases with diffuse gland involvement, whereas an increase of T3 alone was present in 3 patients with unilobar involvement. In the latter group and in the 2 patients with a nodular form T4, FT3 and FT4 levels were within normal limits. Interruption of the pituitary-thyroid feed-back mechanism with absence of thyrotropin response to TRH occurred in 11 patients, independent of whether thyroid hormone concentrations were elevated or normal. In one patient only with unilateral involvement, TSH responsiveness to TRH was normal while 131I uptake was not raised by exogenous TSH, indicating diffuse cellular damage. The normal values of FT3 and FT4 found in patients with normal T3 and T4 levels seem to exclude the possibility that the free hormones are responsible for the interrupted feed-back which represents the main cause of suppressed iodine uptake. However, it is possible that the pituitary-thyroid axis is responding to transient or light increases of free and total T3 and T4 still within their 'normal range'.
Incomplete separation of radioiodinated thyroid hormones in serum using specific antibodies
Authors: Perrild H. , Skovsted L. , Christensen L. Korsgaard 
Published: December 2008

Abstract.
Alkaline Sephadex G-25 columns were used to separate labelled 3,5,3',5'-thyroxine, 3,5,3'-triiodothyronine, 3,3',5'-triiodothyronine and 3,3'-diiodothyronine from the serum binding proteins followed by a quantitative elution of each hormone by coupling to its respective antibody. It is shown that although these antibodies (diluted 1:1500–1:100 000) in our radioimmunoassays are highly specific they show a high degree of non-specific binding when they are used in the concentrations necessary to get a maximal recovery of the hormones in column separating experiments.
Effect of neonatal hypothyroidism on maturation of nuclear triiodothyronine (T3) receptors in developing rat brain
Authors: Ishiguro Kazumasa , Suzuki Yukichi , Sato Tamotu 
Published: December 2008

Abstract.
Changes of nuclear T3 receptors during brain maturation were studied in normal and hypothyroid rats. In normal rats, the higher receptor concentration present in the neonatal period (0.35 ± 0.04 ng T3/mg DNA) decreased at the age of 14 days (0.25 ± 0.02 ng T3/mg DNA), and remained at this level thereafter to 35 days of age (0.25 ± 0.03 T3/mg DNA). In contrast, hypothyroid rats showed a significantly higher concentration than that found in an age-matched control group at the age of 14 days (0.38 ± 0.07 ng T3/mg DNA), and maintained this level up to 35 days of age (0.37 ± 0.03 T3/mg DNA). The binding affinity was similar in both groups and throughout maturation (mean ± sd in normal groups: 1.9 ± 0.3 × 1010m−1, in hypothyroid groups: 1.7 ± 0.2 × 1010m−1). Plasma T3 concentrations showed changes reciprocal to those in the binding capacity of T3 receptors. These results indicate that nuclear T3 receptors in rat brain mature by the age of 14 days, in association with a decrease in binding capacity, and this process seems to be T3-dependent. The physiological role of the high concentration of T3 receptors observed in neonatal and hypothyroid rat brain during development is at present not clear.
Oestrogen metabolism in adult rat's brain
Authors: Reddy Vangala V. R. , Rajan Renga , Daly Michael J. 
Published: December 2008

Abstract.
In vitro incubation of pituitary, hypothalamus and cerebral cortex with [3H]oestrogens revealed that the oestrogens are actively metabolized by these tissues. The covalent binding of oestrone and oestradiol to acid precipitable proteins was observed. Pituitary from male rats exhibited higher covalent binding of oestrogens than females. The 2-hydroxylation was found to be greater than 16-hydroxylation. Furthermore, male pituitary exhibited higher 2-hydroxylation of oestrogens than females. No such sexual dimorphism was observed in 16-hydroxylation. C17-reduction was found to be greater than oxidation in these tissues. Furthermore, the C17-reduction in pituitary and hypothalamus from females was greater than males, which is in contradistinction to protein binding and 2-hydroxylation of oestrogens. In both male and female animals the pituitary was metabolically more active than hypothalamus and cortex. In addition, oestradiol was hydroxylated more than oestrone either at 2- or 16-positions. These results indicate that in central nervous system and pituitary the oestrogens are metabolized preferentially by 2-hydroxylation pathway and it is suggested that the in situ metabolism of oestrogens in neuroendocrine tissues may be important in the control of oestrogen effects on neuroendocrine function and sex behaviour.
Parathyroid hormone response to hypocalcaemia following hypercalcaemia
Authors: Blum J. W. , Kunz P. , Rodriguez S. M. , Fischer J. A. 
Published: December 2008

Abstract.
Experiments were designed to study the ability of calcium infusions to suppress parathyroid hormone (PTH) responses to hypocalcaemia, induced by iv infusions of ethylene-glycol-bis(β-aminoethylether)N,N′-tetraacetate (EGTA). When plasma calcium (Ca) was raised for 60 min to levels higher then 2.6 mmol/l, PTH responses to a subsequent fall of Ca due to EGTA infusions for 7 min were significantly reduced (P < 0.02) or abolished when compared to PTH responses during 7-min EGTA infusions in normocalcaemic animals. CaCl2 infusions lasting for 10 min only, however, did not cause a significant reduction of PTH responses to subsequent 7-min EGTA infusions. The results demonstrate, that raised Ca reduced PTH available for immediate release. This effect was time-dependent, since it was only seen, when CaCl2 was infused for more than 10 min prior to the administration of EGTA.
Follicular development in the neonatal mouse ovary; effect of epidermal growth factor
Authors: Lintern-Moore S. , Moore G. P. M. , Panaretto B. A. , Robertson D. 
Published: December 2008

Abstract.
The growth of the ovary has been studied in the mouse after administration of epidermal growth factor (EGF). Newborn females injected daily with EGF for the first 5 days of life showed a retardation of ovarian development. The number of follicles in the resting pool (small follicles) was significantly greater than in control animals and there were fewer growing follicles at more advanced stages of development (types 3b and 4). The percentage of mitotic figures in the follicular and surface epithelia of the ovary and the epithelium of the extraovarian rete was also significantly reduced after EGF. The results indicate that EGF may inhibit rather than promote the growth of follicles in the neonatal mouse ovary in vivo.
Influence of sex hormone binding globulin and serum albumin on the conversion of androstenedione to testosterone by human erythrocytes
Authors: Egloff M. , Savouré N. , Tardivel-Lacombe J. , Massart C. , Nicol M. , Degrelle H. 
Published: December 2008

Abstract.
The influence of human serum albumin and sex hormone binding globulin (SHBG) on the enzymic conversion of androstenedione to testosterone in human erythrocytes was investigated in vitro. Total plasma and albumin delayed the conversion rate of androstenedione, while SHBG increased it markedly. The effect of SHBG was largely abolished by heating to 60°C for 1 h and by saturating its binding sites by DHT. The effect of both proteins was found to be related to their concentration. It appears that the binding sites of albumin provide a mechanism for retarding androstenedione uptake by the erythrocytes and that the high binding affinity of SHBG for testosterone facilitates the diffusion of this steroid out of the cell and thus, displaces the chemical equilibrium within the cell.
Radioimmunoassay of 6α-methyl-17α-acetoxyprogesterone (MAP) in plasma of sheep during and after oral administration
Authors: Sletholt Kjersti 
Published: December 2008

Abstract.
Plasma concentrations of MAP during and after oral administration were measured by a radioimmunoassay technique capable of detecting 2 pg of MAP in 0.1 ml of unextracted plasma. Four ewes were individually subjected to treatment with 50 mg MAP orally per day in 10 days. The maximum plasma concentrations of MAP during the treatment varied considerably among the 4 ewes, the highest recorded was 3.5 ng/ml and the lowest 2.1 ng/ml.
The plasma level of MAP declined to a non-detectable level 5 days after the last administrations in 2 ewes, in the other 2 ewes the level was non-detectable after 6 and 7 days, respectively.
Effect of human growth hormone on the distribution of amino acids between plasma and erythrocytes in pituitary dwarfism
Authors: Uchigata Yasuko , Sato Tamotu 
Published: December 2008

Abstract.
To examine the effects of human growth hormone (hGH) on amino acid (AA) transport across the erythrocyte membrane, simultaneous determinations of 14 acidic and neutral AA concentrations in red cells and in plasma, and of gamma-glutamyltranspeptidase (GGTP) activity in red cell membrane were performed in 10 patients with pituitary dwarfism before and/or after hGH therapy. Blood samples were obtained at 0, 1, and 2 h after 4 IU of hGH injection. As AA concentrations in red cells showed wide fluctuations physiologically, samples from 5 normal children at the same intervals served as control. AA distribution was expressed as the concentration ratio of red cell to plasma (R/P). Aspartate and glutamate (group I AAs) showed great intracellular fluctuation concomitantly, which did not appear to be associated with hGH administration. R/P values of most of AAs were significantly decreased in untreated patients (P < 0.01–0.001 vs control), and changes after hGH were very small. In contrast, GH-treated patients exhibited large variance of changes in R/P of threonine, serine, glycine and alanine (group II AAs) at 2 h after hGH loading. However, R/P ratio of cystine, valine, methionine, isoleucine, leucine, tyrosine and phenylalanine (group III AAs) remained low or further depressed by hGH therapy. GGTP activity was also reduced in the untreated patients, while GH-treated patients revealed normal or supranormal GGTP activities. Between GGTP activity and integrated R/P of group II and III AAs, a statistically significant correlation was noted (r = 0.766, P < 0.001). These results suggest that physiologically a dynamic equilibrium exists between AAs in red cells and those in plasma, the transport system of which appears to be different in each group of AAs. hGH seems to exert promoting effects on the shift of AAs across the red cell membrane, at least in part by the activation of gammaglutamyl cycle.
Kinins in relation to renin activity in renal and inferior caval veins in normal individuals and patients with primary aldosteronism
Authors: Hulthén Lennart , Jonsson Kjell , Lecerof Harry , Hökfelt Bernt 
Published: December 2008

Abstract.
Blood kinin concentration and plasma renin activity (PRA) were determined in the renal veins and in the inferior caval vein (ICV) below the level of the renal veins in 9 normal individuals (5 men and 4 women) and 7 patients with primary aldosteronism (3 men and 4 women).
PRA in the renal veins and ICV was significantly lower and plasma aldosterone concentration in ICV significantly higher in the patients as compared to the normals. Kinin concentration in the renal veins and ICV did not differ significantly between the patients and the normals (0.31 ± 0.04 (mean ± sem) vs 0.45 ± 0.03 and 0.27 ± 0.05 vs 0.45 ± 0.06 μg/l, respectively).
In the normal individuals kinin concentration and PRA were inversely related in the left renal vein (r = −0.80; P < 0.02), whereas this relation did not reach statistical significance in the right renal vein (r = −0.60; P < 0.10). Kinin concentration in both renal veins was positively correlated to kinin concentration in ICV (r = 0.73; P < 0.05 and r = 0.83; P < 0.02 for the right and left renal vein, respectively).
These results indicate that intrarenal kinin formation and renin release are inversely related in normal subjects. Furthermore, they suggest that one and the same enzyme, possibly renal kallikrein, may be implicated in the kinin formation in the systemic as well as in the renal circulation. Intrarenal kinin formation seems not to be increased in primary aldosteronism.