bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous perfusion of [4-14C]oestriol and [6,9-3H2]oestriol 16α-monoglucuronide through the isolated rat liver
Authors: Höller M. , Weber H. , Breuer H. 
Published: December 2008

Abstract.
The uptake of [4-14C]oestriol by the isolated perfused rat liver is 3.8 times faster as compared to that of simultaneously perfused [6,9-3H2]oestriol 16α-monoglucuronide. During perfusion the concentration of both radioactive oestrogens decreased exponentially in perfusion medium (apparent kel: 0.061 min−1 and 0.016 min−1, respectively). [6,9−3H2]Oestriol 16α-monoglucuronide was metabolized only to a small extent; more than 92% was secreted unchanged into the bile where it was highly concentrated (1800 nmol/g). In contrast [4-14C]oestriol was extensively metabolized; it was mainly hydroxylated at C-atom 2, leading to a rapid increase in the concentration of 2-hydroxyoestriol in the perfused medium. This metabolite was quickly taken up by the liver during recirculation and subsequently either methylated or sulphated. 2-Hydroxyoestriol monosulphate was glucuronated to 2-hydroxyoestriol 16α-monoglucuronide 3-sulphate, which was rapidly excreted into the bile. No double conjugate was formed when [6,9-3H2]oestriol 16α-monoglucuronide was perfused; this is additional evidence for the correctness of the assumption that monoglucuronides cannot serve as precursors of sulphoglucuronides.
Ovulation in the rabbit following intraventricular and intravenous administration of synthetic Gn-RH
Authors: Bruni J. E. , Montemurro D. G. , Clattenburg R. E. 
Published: December 2008

Abstract.
A comparison was made of the efficacy of intravenously (iv) and intraventricularly administered synthetic Gn-RH in inducing ovulation in conscious and urethane anaesthetized rabbits. Via the iv route of administration, the minimum dose of Gn-RH required to induce ovulation in all animals of the conscious group was 300 ng/kg body weight. This is in contrast to the larger systemic dose (400 ng/kg body weight) of Gn-RH required to achieve the same results in urethane anaesthetized but otherwise identically treated rabbits. This suggests that although ovulation is not blocked by an anaesthetic dose of urethane (1.25 g/kg), the ovulatory response is altered in some way by the anaesthetic. When administered intraventricularly, the minimum dose of Gn-RH required to induce ovulation in anaesthetized animals was only 100 ng/kg body weight or 25% of the equivalent systemic dose. Systemically ineffective doses of Gn-RH (≤ 200 ng/kg body weight) also induced ovulation in the anaesthetized group when administered via the third cerebral ventricle.
All animals that ovulated did so between 13 and 16 h following Gn-RH administration and the number of ova recovered paralleled the number of ruptered follicles. A graded increase in the number of ova released with dosage of Gn-RH was not observed.
In this study, the smaller effective dose requirement for intraventricularly administered decapeptide supports the view that Gn-RH in the CSF circumvents the general circulation and reaches the portal vasculature directly via the median eminence.
Oestrogens and anti-oestrogens show dissociation between early uterine vascular responses and uterotrophic effects in mice
Authors: Arvidson Nils Gunnar , Terenius Lars 
Published: December 2008

Abstract.
The structure-activity relationships of various natural and synthetic oestrogens, anti-oestrogens and some other steroid hormones with respect to early uterine albumin accumulation (EAV) was studied in spayed mice. The results were compared with the activity of these agents to produce a late anabolic response (LAR). The potency ranking order among the oestrogens with respect to EAV was found to be oestradiol-17β, > oestriol, > meso-hexoestrol, > erythro-deoxyhexoestrol, > ent-oestradiol-17β, > (-)methallenestril phenol. Generally the oestrogens were much more potent with respect to EAV than LAR. No correlation was found when the ability to promote EAV and LAR was compared.
Among other agents tested for effect on the EAV, progesterone, the synthetic progestogen, DU-41165 and the anti-hormones MER-25 and U-11100A (nafoxidine) showed no effect. However, hydrocortisone diminished EAV, while dihydrotestosterone increased EAV substantially.
Plasma prolactin concentrations during conception and the first ten weeks of human pregnancy
Authors: Lenton E. A. , Cripps K. , Sulaiman R. , Sobowale O. , Ryle M. , Cooke I. D. 
Published: December 2008

Abstract.
Plasma prolactin concentrations were measured daily throughout 20 cycles in which conception occurred and for several weeks during early pregnancy. Thirteen of the pregnancies were 'spontaneous' (i.e. without exogenous pharmacological stimulation) and 7 occurred during either clomiphene or bromocriptine treatment. Prolactin concentrations were fairly stable throughout the conception cycles until shortly after the time of the first missed menses. From this time concentrations rose gradually to reach a mean concentration of 1250 mU/1 60 days after ovulation. However, there were marked fluctuations from day to day within individuals and considerable variation in the magnitude of the prolactin rise between subjects. Three subjects were mildly hyperprolactinaemic and although prolactin levels remained slightly elevated throughout the study period, this did not affect the outcome of pregnancies.
Testosterone and dihydrotestosterone in amniotic fluid and foeto-placental membranes from the guinea pig
Authors: Rigaudière N. 
Published: December 2008

Abstract.
Testosterone (T) and dihydrotestosterone (DHT) in the amniotic fluid (AF) and foeto-placental membranes (FPM) (yolk-sac + amnion) from 180 male and female guinea-pig foetuses were determined by radioimmunoassay on days 28, 32, 36, 40, 44, 48, 52, 56, 60, 64 of gestation. In male foetus the evolution of androgens in the fluid is characterized by two sharp rises, the former at the time of sexual differentiation on day 32 (T = 219.1 ± 39.1 and DHT = 74.7 ± 10.0 fmol/ml) the latter, which affects only DHT, on day 52 (DHT = 68.5 ± 10.3 fmol/ml). In female foetus, AF T concentrations (mean = 36.3 fmol/ml) are comparable to the lowest T concentrations observed in male, while DHT concentrations (< 2.5 fmol/ml), are significantly lower than those observed in the male (mean = 28.9 fmol/ml) and without any overlap in the values. Thus, in guinea pig, DHT, but not testosterone allows to predict accurately the foetal sex at any stage studied. Testosterone and DHT are also present in FPM and their concentrations were comparable for male and female foetuses in most stages, values varying between 400 and 1600 fmol/g of tissue with a light predominance of DHT compared with T; in both sexes, general evolution of androgens is marked by a rapid drop between days 28 and 44 followed by a significant increase between days 44 and 64. Possible origins of androgens in AF and FPM are discussed.
2-Chloroadenosine increases calcium mobilization from mouse calvaria in vitro
Authors: Lerner Ulf , Fredholm Bertil B. 
Published: December 2008

Abstract.
The effect of 2-chloroadenosine on bone resorption and on cyclic AMP formation in murine calvarial bones in vitro was investigated. 2-Chloroadenosine increased the release of 45Ca from the cultured bones, but had no effect on dead bones, indicating that the effect is cell mediated. The adenosine analogue remained in the medium for 48 h and caused a transient stimulation of the formation of cyclic AMP. The dose-response curve for the stimulatory effect on cyclic AMP accumulation was linear up to 10−4m. The dose-response curve for 45Ca release was linear from 3 × 10−7 m to 3 × 10−5 m but then showed a decline in the response. 8-Bromo cyclic AMP inhibited the release of 45Ca in 24 h cultures. The initial stimulatory effect on bone resorption by 2-chloroadenosine may therefore not depend on cyclic AMP. The level of inosine increased during culture indicating that adenosine is formed by bone tissue.
Evaluation of Prl secretion in elderly subjects
Authors: Rolandi Ermanno , Magnani Gianni , Sannia Antonello , Barreca Tommaso 
Published: December 2008

Abstract.
Prl secretion was evaluated in 76 elderly patients (71–86 years) without endocrine disorders (38 men and 38 women) in basal conditions, after TRH, sulpiride and levodopa administration and during a 24 h period. An impaired Prl response to the administered drugs was found in the elderly women but not in the men. On the contrary, normal sleep-related serum Prl changes were found in the majority of the subjects studied. These results suggest that the pituitary gland can maintain a good Prl secretory pattern in the elderly.
Use of a single TSH-measurement after oral thyrotrophin releasing hormone: an economical and highly sensitive thyroid screening test
Authors: Platzer Rudolf , Wimpfheimer Claus , Bürgi Hans 
Published: December 2008

Abstract.
The increment of serum TSH after thyrotrophin-releasing hormone (TRH) is usually considered an extremely sensitive thyroid test, particularly useful in borderline disturbances. We evaluated 195 patients by measuring serum TSH before and 3 h after 40 mg TRH po, and by various other thyroid tests.
We found a very tight correlation between the TSH-increment and the 3 h TSH. Thus the TSH-increment can reliably be estimated from the 3 h TSH. The Mann-Whitney test confirmed that the 3 h TSH identified thyroid dysfunction as well as the TSH-increment. The basal TSH can therefore be omitted and we propose the measurement of the 3 h TSH as an initial screening test. This single measurement economically excludes the many euthyroid patients sent for thyroid evaluation from further costly tests.
The effect of starvation and refeeding with oral versus intravenous glucose on serum 3,5-, 3,3'- and 3', 5'-diiodothyronine and 3'-monoiodothyronine
Authors: Jædig Steen , Faber Jens 
Published: December 2008

Abstract.
The effect of complete fasting on the serum concentrations of the iodothyronines 3,5-diiodothyronine (3,5-T2), 3,3'-T2, 3', 5'-T2 and 3'-monoiodothyronine (3'-T1) was evaluated. Fourteen obese women underwent a complete fasting for 4 days. Caloric restriction resulted in the following serum hormone levels (before vs 3. day): T4: 103 vs 109 nmol/l (NS), T3: 1.83 vs 1.24 nmol/1 (P < 0.01), rT3: 0.276 vs 0.407 nmol/l (P < 0.01), 3.5-T2: 70 vs 70 pmol/l (NS), 3.3'-T2: 42 vs 39 pmol/l (P < 0.01), 3',5'-T2: 63 vs 93 pmol/l (P < 0.01), and 3'-T1 60 vs 116 pmol/l (P < 0.01). All subjects were refed with 200 g (800 kcal, 3350 kJ) d-glucose per day in divided doses for 2 days. Refeeding tended to normalize the changed iodothyronine concentrations and there was no difference whether the glucose was administered by the oral (n = 7) or the intravenous route.
It can be concluded that starvation in man is accompanied by profound changes in peripheral metabolism of the T2's and 3'-T1. There seems to be no qualitative difference of the effect on the thyroid hormone metabolism of d-glucose administered by the oral or the intravenous route.
Propranolol does not inhibit sulphonylurea-stimulated insulin secretion in patients with non-insulin dependent diabetes mellitus
Authors: Groop Leif , Tötterman Karl Johan 
Published: December 2008

Abstract.
In a double-blind cross-over trial we compared the effects of placebo and propranolol on iv tolbutamide and oral glipizide-stimulated insulin secretion in 10 noninsulin dependent diabetics. The patients were randomly allocated for 2 weeks treatment with placebo and propranolol 80 mg twice daily. At the end of each period an iv tolbutamide test and an oral glipizide-glucose-test were performed.
Tolbutamide-stimulated insulin secretion was not affected by propranolol. There was no change in blood glucose levels during the iv tolbutamide test (IVTT), which excluded an effect of blood glucose on insulin secretion.
During the oral glipizide-glucose challenge propranolol decreased blood glucose at 60 min (P < 0.01) and increased C-peptide at 0 min (P < 0.01) and 30 min (P < 0.05) compared with placebo.
In contrast to earlier results obtained in animals and healthy subjects propranolol does not inhibit insulin- or C-peptide responses to sulphonylurea in patients with non-insulin dependent diabetes mellitus.
Therapeutic effect of tolbutamide in non-insulin dependent diabetes mellitus (NIDDM). Relation to beta-cell function
Authors: Damsgaard Else M. , Faber Ole , Frøland Anders , Iversen Steffen 
Published: December 2008

Abstract.
The therapeutic effect of tolbutamide (1.5 g daily) in a random sample of patients with non-insulin dependent diabetes mellitus (NIDDM), was studied in a controlled, double-blind cross-over trial of 13 women and 6 men, aged 40–65 years and of 85–155% ideal body weight. The trial comprised C-peptide determinations during a standard carbohydrate rich meal followed by four periods of 3 months in which alternating tolbutamide and placebo were given.
From the beginning to the end of the treatment periods fasting blood glucose was reduced from 11.9 ± 1.1 (mean ± sem) to 10.0 ± 0.8 mmol/l (P < 0.025), glycohaemoglobin from 12.8% ± 0.7 to 11.3% ± 0.5 (P < 0.02) with a close correlation between fasting blood glucose and glycohaemoglobin (r = 0.87, P < 0.001). The observations during the first 3 months of study was not included in the calculations. Fasting C-peptide and fasting insulin concentrations were not significantly altered by tolbutamide treatment.
The effect of tolbutamide was inversely correlated to the C-peptide response to the standard test meal at the start of the trial (r = 0.76, P < 0.001), so that patients with the most pronounced beta-cell failure had the greatest therapeutical effect. The beta-cell response to the test meal could not identify patients, whose fasting blood glucose would be normalized by tolbutamide treatment.
Development of preovulatory follicles and oocytes during the oestrous cycle of mature and aged rats
Authors: Peluso J. J. , Hutz R. , England-Charlesworth C. 
Published: December 2008

Abstract.
The percentage of viable granulosa cells and the viability of the oocyte of each antral follicle on each day of the oestrous cycle of mature and aged rats was determined by trypan blue exclusion and fluorescein diacetate assays, respectively. In mature rats, the number of mid-sized follicles (350–550 μm in diameter) increased from oestrus through di-oestrus. The percentage of viable granulosa cells increased in only mid-sized follicles which contained a viable oocyte. On pro-oestrus, two types of preovulatory follicles (> 550 μm in diameter) were observed in the mature pro-oestrous rat: those with a high granulosa cell viability (> 60%) and a viable oocyte and those with a lower percentage of viable granulosa cells (< 50%) and a non-viable oocyte. This suggests that in mature rats only viable oocytes would be ovulated since presumably, only those preovulatory follicles with a high percentage of viable granulosa cells are able to ovulate.
In aged rats, preovulatory-sized follicles were present on each day of the cycle. The percentage of viable granulosa cells within those preovulatory-sized follicles with nonviable oocytes increased on met-oestrus, decreased on di-oestrus and increased by pro-oestrus. This pattern resulted in the development of 3 to 4 preovulatory follicles per ovary with all preovulatory-sized follicles possessing a high percentage of viable granulosa cells regardless of the functional state of the oocyte. It is proposed that in aged rats, all the preovulatory follicles would ovulate but many of the ovulated oocytes would be defective. This mechanism would account for the lower fertility of these older animals.
The aging Leydig cell: VI. Response of testosterone precursors to gonadotrophin in men
Authors: Murono E. P. , Nankin H. R. , Lin T. , Osterman J. 
Published: December 2008

Abstract.
The effects of a single im injection of human chorionic gonadotrophin (hCG) on circulating testosterone precursor levels at 0, 1–6, 24, 48 and 72 h were examined in normal young adults (mean age 34 years) and normal aged men (mean age 74 years). Basal 08.30–09.00 h concentrations of androstenedione and dehydroepiandrosterone were lower in aged men while progesterone levels were not significantly different from young men. A significant biphasic increase of circulating progesterone was observed in young men, characterized by an early peak at 2 h (33% above basal) and a secondary peak at 24 h (49% above basal). In old men there were no increases in circulating progesterone levels following hCG treatment during the early (1–6 h) or late (24–72 h) periods. There were not discernable increases in circulating dehydroepiandrosterone levels following hCG administration in both groups of men. Androstenedione levels in young men did not change during the first 6 h following hCG but increased significantly at 48 and 72 h, while in old men there was a small peak at 4 h (which was not statistically significant) and a secondary significant rise at 48 and 72 h. However, early and late stimulated absolute levels for androstenedione were lower in the aged population. Thus, there are differences in precursor concentrations in the basal state and in response to hCG in aged men.
Effect of various drugs on the binding of thyrotrophin to thyroid plasma membranes
Authors: Baba Yasuto , Nakao Yoshinobu , Kishihara Michizo , Kobayashi Nobuhisa , Kimoto Hiroyuki , Matsukura Shigeru , Fujita Takuo , Kuma Kanji 
Published: December 2008

Abstract.
Effects of enzyme inhibitors and membraneactive drugs on the binding of 125I-labelled thyroidstimulating hormone (TSH) to human thyroid membranes and membrane adenylate cyclase (AC) activity were studied. FOY®, a synthetic polyvalent proteolytic enzyme inhibitor, Trasylol®, α- and β-adrenergic blocking agents, tranquilizers, anti-histamines and polyene antibiotics enchanced TSH binding in a dose-dependent manner, whereas selective enzyme inhibitors and adrenergic stimulating agents had no effect. Both propranolol and FOY inhibited basal and TSH stimulated AC activity of thyroid membranes. FOY, as well as propranolol was found to have protective effects on hypotonic erythrocyte lysis. These results suggest that propranolol and FOY increased TSH binding by the same mechanism, probably the so-called membrane-stabilizing effects. Although the detailed mechanisms underlying the increased TSH binding by these drugs remain unknown, they may change the membrane structure, thereby enhancing the TSH receptor affinity.
Effects of somatostatin on parathyroid hormone levels and on responses of parathyroid hormone to β-adrenergic agonists and hypocalcaemia
Authors: Blum J. W. , Fischer J. A. 
Published: December 2008

Abstract.
Experiments were designed to study the effect of exogenous somatostatin (S) on basal levels or parathyroid hormone (PTH) and on PTH responses to isoproterenol (ISO), adrenaline (A) or ethyleneglycol-bis (β-aminoethylether) N,N'-tetraacetate (EGTA) in cattle. During S infusions (6.11 nmol injected iv as a bolus and 0.82 nmol/kg/min infused iv for 30 or 60 min) plasma levels of PTH and calcium (Ca) did not change, whereas concentrations of immunoreactive insulin (IRI) decreased significantly (P < 0.01). In response to ISO (0.09 nmol/kg/min) or EGTA (5.6 μmol/kg/min, depressing plasma Ca by 0.27 nmol/l) PTH levels were similarly increased (P < 0.05) both in the absence and presence of S. On the other hand, S supressed IRI responses to ISO. During 60-min infusions of EGTA (3.15 μmol/kg/min) plasma Ca fell to significantly lower levels (P < 0.01) during simultaneous infusions of S than in the absence of exogenous S, while the magnitude of PTH responses was similar. The results do not support a role of somatostatin on basal PTH levels and on PTH responses to β-adrenergic agonists or hypocalcaemia under conditions, in which S markedly lowers IRI levels and IRI responses to ISO. However, S apparently reduces Ca mobilisation during abrupt hypocalcaemia.
Ontogeny of circulating gastrin and pancreatic polypeptide in the foetal sheep
Authors: Shulkes Arthur , Hardy Kenneth J. 
Published: December 2008

Abstract.
Hypoacidity and hypergastrinaemia are reported in the newborn human. To investigate the ontogeny of gastrin, plasma gastrin concentrations were measured in chronically cannulated foetal sheep from 100 days gestation to term (145 days) and up to 16 days following delivery. Plasma pancreatic polypeptide (PP) concentrations were measured as a marker of vagal activity. Compared with adult values, foetal plasma gastrin concentration was low at 101–105 days, being 7 ± 1 pmol/l (mean ± sem) but was greater than adult values from 130 days gestation and increased to 47 ± 5 at 141–145 days, and 90 ± 13 at 1–5 days post-partum. Maternal plasma gastrin levels during these periods ranged between 21 and 29 pmol/l and was not related to gestational age. Similarly, maternal plasma PP levels, which varied between 220 and 400 pmol/1, did not correlate with gestational age and did not differ significantly from non-pregnant sheep. Foetal plasma PP was low, 20 ± 3 at 101–105 days, rose to 92 ± 17 at 141–145 days, and increased to adult levels in the first week post-partum. Basal foetal and maternal plasma PP were inhibited by iv atropine injection. The increase in plasma PP may represent a maturity of vagal influence. Gastrin and PP have a trophic action on the gastro-intestinal tract, so the observation of significant levels of circulating gastrin and PP in the foetus suggests that they may be involved in maturation of the gastro-intestinal tract.
ACTH suppression after oral administration of cortisone in Addisonian and adrenalectomized patients
Authors: Aanderud Sylvi , Myking Ole Langeland , Bassøe Hans H. 
Published: December 2008

Abstract.
Plasma cortisol and the corresponding ACTH concentrations were determined before, and for 6 h following a single oral dose of 25 mg cortisone acetate in 7 patients with Addison's disease, 6 patients adrenalectomized for Cushing's disease and 1 patient adrenalectomized for congenital adrenal hyperplasia. The basal plasma cortisol concentrations 12 h after an evening dose of cortisone acetate 12.5 mg were below 100 nmol/l, and the corresponding ACTH concentrations were markedly elevated in all the patients. Great interindividual variations were found in cortisol peak concentrations (Cmax) and the time to peak values, but without significant differences between the two patient groups. The maximal ACTH suppression occurred within 60–330 min after the cortisol Cmax. and was not significantly different in the two groups. The suppressed plasma ACTH concentrations were considerably above normal in 3 of the patients with Addison's disease and in 4 of the 6 patients adrenalectomized for Cushing's disease, including 2 patients with Nelson's syndrome.
A similar degree of impaired ACTH suppression in patients with Addison's disease as in adrenalectomized patients suggests the occurrence of a secondary hypothalamic-pituitary dysfunction with ACTH hypersecretion in Addison's disease. The adequacy of the commonly used adrenocortical replacement therapy and its possible relation to the impaired ACTH suppression is discussed.
Demonstration of γ-trace in normal endocrine cells of the adrenal medulla and in phaeochromocytoma
Authors: Löfberg H. , Nilsson K. E. , Strömblad L.-G. , Lasson Å. , Olsson S.-O. 
Published: December 2008

Abstract.
γ-Trace was demonstrated by the immunohistochemical peroxidase/anti-peroxidase technique to occur in normal chromaffin cells of the adrenal medulla from African green monkey, capuchin monkey and beagle dog and in the cells of a norepinephrine-producing human phaeochromocytoma. The presence of γ-trace in the endocrine epithelial cells of the adrenal medulla suggests that γ-trace might be related to the neuroendocrine system.