bluuebunny/crossref_metadata_2025_split huggingface dataset:
Age-related changes in the feedback regulation of gonadotrophin secretion in the immature and adult male rabbit
Authors: Berger M. , Jean-Faucher Ch. , De Turckheim M. , Veyssière G. , Jean CI. 
Published: December 2008

Abstract.
Male rabbits were castrated at infantile (30 days), peripubertal (60 days) and adult (7–8 months) stages. Two different doses of testosterone were injected 10 days after castration (5 injections at 12 h intervals). Plasma LH and FSH were determined by RIA 1,5 and 10 days after castration and 1 h after the last injection of testosterone. The response of both gonadotrophins to castration was age-dependent. In 30 day old castrated males LH was not significantly modified and FSH had increased only 10 days after castration. In 60 day old and adult males FSH and LH levels were increased 24 h after castration and continued to rise as time progressed. For both gonadotrophins, the response of adult males to castration was higher than that of immature animals. At all stages studied, the highest dose of testosterone (250 μg/kg body weight) depressed post-castration LH and FSH levels. Twenty-five μg of testosterone per kg body weight was effective to depress LH levels only in 30 day old males, suggesting a change in the hypothalamic-pituitary unit to the negative feedback of androgens.
These findings suggest that there are marked changes in the hypothalamic-pituitary unit around the beginning of the peripubertal stage. These changes could play a determinant role in the onset of puberty.
The incidence of occult thyroid disease associated with thyroid antibodies identified on routine autoantibody screening
Authors: Tanner A. R. , Scott-Morgan Lindsay , Mardell R. , Lloyd R. S. 
Published: December 2008

Abstract.
The presence of thyroid microsomal and/or thyroglobulin antibodies has been recorded over a 2 year period in 15000 consecutive autoimmune profile requests. Where there had been no initial clinical suspicion of thyroid diseases, 332 requests showed positive thyroid antibodies, and of these 63 (19%) had abnormal in vitro thyroid function tests (TFT). No differences were observed between the abnormal and normal groups with respect to the presence of different autoantibodies or to the age and sex distributions. Of these subjects with clinically unsuspected hypothyroidism but with abnormal TFTs, 29% were commenced on thyroxine therapy and experienced a symptomatic improvement, 25% remain well on no therapy and 9% continue on no treatment but with symptoms possibly attributable to hypothyroidism. 3% became clinically hypothyroid during a follow-up period of 2 years. 5% died of unrelated causes and there was inadequate follow-up information on the remainder. This study provides further confirmation that when thyroid antibodies, and in particlar thyroid microsomal antibody, are found unexpectedly, a significant proportion of patients will have biochemical evidence of hypothyroidism and may benefit from appropriate treatment.
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.
Equimolar concentrations of [4-14C]oestriol and [6,9-3H2]oestriol 16α-monoglucuronide were simultaneously perfused through isolated rat livers. Oestriol was hydroxylated to 2-hydroxyoestriol and 6ξ-hydroxyoestriol; 2-hydroxyoestriol was further methylated to 2-methoxyoestriol. Oxidoreduction of oestriol led to the formation of 16α-hydroxyoestrone, 16-oxooestradiol-17β and 16-epioestriol. In addition, two dehydroxylation products, namely oestrone and oestradiol-17β were found. The metabolites formed from oestriol were partly conjugated to monoglucuronides, monosulphates and sulphoglucuronides.
About 80% of the oestriol perfused was hydroxylated at C-atom 2. Most of the 2-hydroxyoestriol formed was either methylated (about 37%) or sulphated (about 55%). Only small amounts (less than 2%) of the catecholoestrogens formed were methylated as well as sulphated. The 2-hydroxyoestriol monosulphates accumulated in the liver. After their conjugation with glucuronic acid, the double conjugates formed were immediately excreted into the bile. In fact, 2-hydroxyoestriol 16α-monoglucuronide 2(3?)-monosulphate comprised by far the main biliary metabolite of [4-14C]oestriol, followed by oestriol 16α-monoglucuronide and 2-methoxyoestriol 16α-monoglucuronide.
No tritiated sulphoglucuronides were detected, thus indicating that the monosulphates are the immediate precursors of the double conjugates. [6,9-3H2]Oestriol 16α-monoglucuronide was metabolised only to a small extent. After its uptake into the liver more than 90% of this conjugate was secreted unchanged into the bile. The remaining part was hydrolysed; the oestriol liberated followed the same metabolic reactions as those found for [4-14C]oestriol. This indicates that the 16α-glucuronide of oestriol is not metabolised to any appreciable extent.
17α-Hydroxylase deficiency syndrome associated with bilateral streak gonads and impaired development of Müllerian ducts derivatives
Authors: de Gennes Jean-Luc , Jambart Sélim , Turpin Gérard , Elkik François , Roger Marc 
Published: December 2008

Abstract.
We report severe 17α-hydroxylase deficiency in a 17 year-old black girl with 46,XX genotype. The diagnosis was suspected because of primary amenorrhoea, absence of sexual maturation, hypertension and hypokalaemia with renal potassium wasting. Endocrine investigation revealed low basal levels of all steroid hormones which require 17α-hydroxylation for biosynthesis (i.e. glucocorticoids, androgens and oestrogens). No increase in their basal levels was seen following adrenal stimulation, indicating a severe block. Plasma concentrations of ACTH, FSH and LH were elevated as were progesterone, 11-deoxycorticosterone and corticosterone. Plasma renin activity was suppressed and aldosterone levels were very low. After 4 months of glucocorticoid replacement therapy, aldosterone was still low, even though the suppression was otherwise effective. Our case is unusual because bilateral streak gonads and impaired development of Müllerian ducts derivatives were also present. To our knowledge, a similar case has never been reported before.
Diurnal rhythm of total and free concentrations of serum corticosterone in the rat
Authors: D'Agostino JoBeth , Vaeth Gregory F. , Henning Susan J. 
Published: December 2008

Abstract.
Daily variations in serum concentrations of total and free corticosterone and corticosteroid-binding globulin (CBG) were determined at 4 h intervals in male rats maintained on a 12:12 h light/dark cycle (lights on at 05.00 h). Total corticosterone concentrations exhibited a classical rhythm with peak values occurring at the onset of dark (17.00 h). Serum CBG concentrations displayed daily fluctuations but these appeared to be non-rhythmic in nature.
The % free corticosterone exhibited a diurnal rhythm with peak values occurring during the dark phase. When absolute concentrations of free corticosterone were calculated, the profile could be superimposed on that of total corticosterone with the zenith at the onset of the dark phase (17.00 h) and the nadir coinciding with the onset of light (05.00 h). These data suggest that the primary determinant of the rhythm in free corticosterone concentrations is the daily rhythm in total corticosterone.
Placental secretion of prolactin, ACTH and immunoreactive β-endorphin during pregnancy
Authors: Demura Reiko , Odagiri Emi , Yoshimura Masayo , Jibiki Kazuko , Adachi Tomoko , Shirota Mariko , Demura Hiroshi , Shizume Kazuo , Oouchi Hiroko 
Published: December 2008

Abstract.
The placental secretion of Prl, ACTH and immunoreactive (IR)-β-endorphin were examined in early and later pregnancy with a perfusion method and by determining tissue concentrations of these hormones. Prl was secreted mainly from decidual tissue during 5–6 h long perfusions. Tissue concentrations of Prl were also significantly higher in decidual than in trophoblastic tissues. In contrast, the tissue concentrations of hCG, hPL, ACTH and IR-β-endorphin were significantly higher in trophoblastic than in decidual tissues. Production of hCG and hPL was predominantly demonstrated in trophoblastic tissues by the perfusion method but ACTH and IR-β-endorphin were too low to be detected by perfusion.
Binding of 5α-dihydroprogesterone to proteins in human pregnancy serum
Authors: Lea Oscar A. 
Published: December 2008

Abstract.
The binding of 5α-dihydroprogesterone (DHP)1 to proteins in pregnancy serum has been investigated and compared with the binding of progesterone. Characteristic properties of the DHP-serum protein interaction were unsaturability, low affinity and poor complex stability. Fractionation of serum using a variety of protein separation techniques, revealed that DHP interacts with several proteins. At low temperature (0–4°C) albumin appeared to be the principal binding component whereas higher temperatures seemed to favour binding to β-lipoproteins and α2-macroglobulin. Binding to specific binding proteins such as the corticosteroid binding globulin (CBG) and the sex hormone-binding globulin, (SHBG) were detectable but appeared to be quantitatively unimportant.
Progesterone showed a similar multicomponent interaction but differed from DHP in the extent of binding to CBG. Binding of either hormone to the α1-acid-glycoprotein was negligible.
The present study shows that the high endogenous DHP levels present in pregnancy sera are caused by factors other than high affinity protein binding.
Correlation of the HLA-A1,B8 haplotypes with circulating autoantibodies in a family with increased incidence of autoimmune disease
Authors: Valenta Lubomir J. , Bull Robert W. , Hackel Emanuel , Bottazzo Gian Franco 
Published: December 2008

Abstract.
Two cases of Addison's disease, two cases of scleroderma, three cases of primary hypothyroidism possibly due to Hashimoto's thyroiditis, three cases of diabetes mellitus, and two cases of ovarian failure and secondary amenorrhoea were diagnosed in a single family. In 44 members of four generations of the family including all the diseased, we have performed HLA typing and measurement of circulating autoantibodies. All diseased patients were older than 12 years, all possessed HLA B8 antigen, and all but two showed specific autoantibodies in their serum. In contrast, none of the family members without HLA B8 developed any of the autoimmune diseases in spite of the fact that in 13 of them some circulating autoantibodies were demonstrable in the serum. It is concluded that genetic factors play an essential role in the development of autoimmunity in the studied family. The individuals acquire circulating autoantibodies as they develop the disease. Environmental factors play a secondary role as evident from the age dependence. HLA typing can become an important diagnostic tool in identifying the individuals at a risk of autoimmune disease. Detection of circulating serum autoantibodies alone correlated poorly with the autoimmune disease.
Catecholamine turnover in the brain and the regulation of luteinizing hormone and corticosterone in starved male rats
Authors: Pirke K. M. , Spyra B. 
Published: December 2008

Abstract.
The effect of starvation was studied in male Wistar rats. After only 2 days of food deprivation, LH concentrations in serum are greatly suppressed, while a significant increase in plasma corticosterone occurs after 5 days' starvation. The noradrenaline and dopamine turnover in the basal hypothalamus is decreased after 2 days. The catecholamine turnover is also reduced in the preoptic area, and in the median eminence. Injection of the catecholamine precursor l-dopa (100 mg/kg) can prevent the increase of plasma corticosterone, but not the decrease of LH. The α-agonist clonidine (150 μg/kg), but neither the β-agonist salbutamol (0.5 mg/kg), nor the dopamine agonist apomorphine (1.0 mg/kg) can prevent the starvation induced corticosterone increase. The decrease of plasma LH is not influenced by the dopamine or noradrenaline agonists. From these data, it appears that a decreased activity of noradrenergic neurons may be responsible for the corticosterone increase in the plasma of starved rats.
Prl, TSH, GH and LH responses to metoclopramide and breast-feeding in normal and hyperprolactinaemic women
Authors: Andersen A. Nyboe , Tabor Ann 
Published: December 2008

Abstract.
In order to evaluate whether hyperprolactinaemic patients have an increased or decreased central dopaminergic tonus, we compared the serum Prl, TSH, GH and LH responses to metoclopramide (10 mg iv) and to breast-feeding in normal women (n = 8) and hyperprolactinaemic patients (n = 8).
Prl increments to metoclopramide were significantly (P < 0.05) impaired in hyperprolactinaemic patients. Serum TSH increased significantly after metoclopramide both in normal and hyperprolactinaemic patients (P < 0.025), but no significant differences were found between the two groups regarding TSH, GH or LH levels.
Hyperprolactinaemic pateints had no acute response to suckling while significant increments of Prl and GH (P < 0.025) occurred in normal women.
Our data indicate that the central dopaminergic tonus was not altered in hyperprolactinaemic patients, but showed regulatory dysfunction of both Prl and GH. The concept of a dopaminergic inhibition of TSH secretion was confirmed.
Testosterone inhibition of LRH-induced luteinizing hormone release by cultures of rat anterior pituitary cells: effect of inhibitors of steroid 5α reductase
Authors: Leveque N. W. , Grotjan H. E. 
Published: December 2008

Abstract.
Cultures of rat anterior pituitary cells were utilized to examine the role of 5α reduction in the inhibitory action of testosterone on LRH-induced LH release. Cultures were pre-treated with steroids for 48 h and then incubated 6 h with steroids plus 5 × 10−10 m LRH, the approximate EC50 for LH and FSH release. Testosterone inhibited LRH-induced LH release with an IC50 of approximately 2 × 10−10 m. However, even relatively high concentrations of testosterone did not completely inhibit LRH-induced release. Testosterone (and dihydrotestosterone) appeared to antagonize LRH-induced LH release but did not markedly affect 48 h basal release or LH synthesis as judged by the quantity of LH released plus that remaining intracellularly. Progesterone (10−6 M) and heparin (1000 U/ml) were used as inhibitors of anterior pituitary steroid 5α reductase. Progesterone, when combined with testosterone, markedly shifted the testosterone inhibition curve to the right (approximately 340-fold) but did not shift the dihydrotestosterone inhibition curve. Heparin also slightly shifted the testosterone inhibition curve (approximately 2.4-fold) to the right. These observations support the hypothesis that the mechanism of action of testosterone on the anterior pituitary involves 5α reduction.
The influence of vasopressin on oxytocin-induced changes in urine flow in the male rat
Authors: Forshing Mary L. , Brimble M.J. , Balment R. J. 
Published: December 2008

Abstract.
Oxytocin administration in rats infused with hypotonic saline is associated with a saliuresis and altered renal water excretion. The role of vasopressin in determining the pattern of oxytocin-induced changes in urine flow was investigated in Long Evans and vasopressin-deficient Brattleboro rats, which exhibit contrasting diuretic and antidiuretic responses to oxytocin. Ethanol anaesthesia and water loading in Long Evans suppressed plasma vasopressin levels and was associated with an antidiuretic response to oxytocin. Vasopressin administration in the Brattleboro rat reversed the oxytocin-induced antidiuresis normally observed in vasopressin dificiency. These results taken with previous observations, have been interpreted as indicative that oxytocin acts as a weak agonist at the renal vasopressin receptor. When plasma vasopressin is suppressed or absent oxytocin acts as a weak antidiuretic agent, but in the presence of higher vasopressin levels a diuretic response to oxytocin is seen which follows displacement of vasopressin, the more potent antidiuretic agent, from the renal receptor.
Familial elevations of total and free thyroxine in healthy, euthyroid subjects without detectable binding protein abnormalities
Authors: Maxon Harry R. , Burman Kenneth D. , Premachandra Bhartur N. , Chen I-Wen , Burger Albert , Levy Phillip , Georges Leon P. 
Published: December 2008

Abstract.
Elevations of serum thyroxine without thyrotoxicosis or binding protein abnormalities have been documented in 8 of 13 family members, representing 4 generations. This syndrome appears to represent an elevated threshold for the amount of free thyroxine substrate required to maintain adequate T3 production form the peripheral monodeiodination of T4. It reiterates the need for a prudent re-evaluation of all clinically euthyroid patients with elevated serum thyroxine concentrations before concluding that they are indeed thyrotoxic.
Standardization of the radioreceptor assay against anti-thyrotrophin receptor antibodies in Graves' disease
Authors: de Bruin T. W. A. , Krol M. C. , van der Heide D. 
Published: December 2008

Abstract.
We studied the possibility of standardizing the radioreceptor assay for the detection of anti-thyrotrophin receptor antibodies, also called thyrotrophinbinding inhibitor immunoglobulins (TBII), to circumvent the problem of inter-assay variability in TBII index calculations. We developed a procedure for conversion of the thyrotrophin-binding inhibition caused by standard amounts (10 mg IgG/ml) of 1.6 m ammonium sulphate precipitates into thyrotrophin-equivalents, i.e. the amount of thyrotrophin required to cause the same thyrotrophin-binding inhibition. We were able to determine a normal range for thyrotrophin-binding inhibition which exhibited little inter-assay variability and was applicable to individual radioreceptor assays. The normal range, expressed in thyrotrophin-equivalents or the logarithm of μU thyrotrophin, was 2.616–3.645, which corresponds to 413–4420 μU. The thyrotrophin-binding inhibition by 1.6 m ammonium sulphate precipitates from sera of 17 untreated patients with Graves' disease was also expressed in thyrotrophin-equivalents. For 15 patients (88%) the thyrotrophin-equivalent values were above the normal range, whereas only 10 patients (59%) had a positive TBII index (using the same sample). This indicated that 5 patients had anti-thyrotrophin receptor antibodies in spite of their negative TBII index. Standardization based on the IgG content of the test samples therefore seems to be imperative. Pig serum 1.6 m ammonium sulphate precipitates, which were tested in a porcine assay system, yielded thyrotrophin-equivalent values that corresponded closely to the normal range for the human assay system, suggesting that the normal range of thyrotrophin-binding inhibition is in the same order of magnitude in porcine and human assay systems.
Enhancement of gonadotrophin induced 17,20-lyase suppression one week after human chorionic gonadotrophin priming
Authors: Smals A. G. H. , Boers G. H. J. , Roose P. H. C. , Pieters G. F. F. M. , Beex L. V. A. M. , Kloppenborg P. W. C. 
Published: December 2008

Abstract.
A single injection of 1500 IU of human chorionic gonadotrophin (hCG) in normal men, induced a block in the conversion of 17-hydroxyprogesterone (17-OHP) to testosterone (T) which reached its maximum 24 h after hCG loading. One week after hCG administration both basal 17-OHP (3.8 ± 0.6 vs 5.1 ± 0.5 nmol/l, P < 0.02) and T levels (15.1 ± 1.7 vs 18.5 ± 2.3 nmol/l, P < 0.05) were about 20% lower than before hCG exposure. The ratio 17-OHP to T (0.29 ± 0.04 vs 0.31 ± 0.04, P > 0.10) was however similar, suggesting recovery from the prior 17,20-lyase suppression at a lower overall capacity of T synthesis.
hCG administration one week after the priming dose elicited an increase in the ratio 17-OHP to T, which was about twice as high as after the first hCG injection.
Together the data suggest: 1) suppression of testicular steroidogenesis proximal to 17-OHP one week after hCG priming, 2) enhanced hCG induced 17,20-lyase suppression one week after hCG exposure.
Instant growth inhibition by low dose oestrogens in excessively tall boys
Authors: van den Bosch John S. G. , Smals Anthony G. H. , Pieters Gerlach F. F. M. , Valk Ignace M. , Kloppenborg Peter W. C. 
Published: December 2008

Abstract.
A major problem in the androgen treatment of escessive height in boys is acceleration of growth velocity especially in the early stages of therapy. Oestrogen treatment in tall girls, in contrast, instantly decelerates growth velocity, probably by its plasma somatomedin lowering effect. As oestrogen administration in male subjects causes a similar somatomedin depression and immediate growth inhibition is also wanted in the treatment of excessive height in boys, the effect of short-term low dose oestrogen therapy (ethinyloestradiol, Ee, Lynoral®, 0.050 mg daily) on growth was studied in 10 constitutionally tall boys.
During oestrogen therapy three week ulnar growth rate (TUG-rate) dropped instantly from 0.84 ± 0.42 to 0.33 ± 0.27 mm (P < 0.02) within 6 weeks. Three week body growth rate also changed significantly from 0.48 ± 0.23 to 0.12 ± 0.37 cm during oestrogen loading (P < 0.05). The magnitude of the latter changes, however, allows only evaluation of the whole group, whereas changes in TUG-rates far exceeded the limits of confidence in most individual boys.
Growth deceleration during Ee was accompanied by a significant decrease in serum alkaline phosphatase activities (from 299 ± 72 U/l before to 240 ± 79 U/l during Ee, P < 0.01), plasma calcium (from 2.45 ± 0.06 to 2.35 ± 0.05 mmol/l during Ee, P < 0.05) and plasma testosterone levels (from 392 ± 128 ng/100 ml before to 27 ± 7 ng/100 ml during Ee, P < 0.005). Within 2 months after stopping Ee administration plasma testosterone levels were normal again (432 ± 282 ng/100 ml).
Testicular size was not affected. Mild reversible gynaecomastia, however, was present in all boys.
The results demonstrate an instant growth decelerating effect of low dose oestrogen administration in tall boys reminiscent to the findings in tall girls under the same low dose regimen. Furthermore these data provide a theoretical base for combining androgens and oestrogens in the early stages of treatment of excessive height in boys in order to antagonize the initial growth accelerating effect of androgens alone.
Hyperprolactinaemia and breast disease as evaluated by xeromammography
Authors: Calhaz-Jorge C. , Cunha C. , Nunes M. C. P. , Sobrinho L. G. 
Published: December 2008

Abstract.
This report compares the xeromammographic patterns of 35 patients with hyperprolactinaemia and 70 (age-matched) normoprolactinaemic controls. It is shown that nulliparous patients have less frequent mammary dysplasia and more patterns of involution than the nulliparous controls. The groups of parous patients and parous controls were similar to each other and both had more involutions and less dysplasia than the nulliparous controls. Hyperprolactinaemia in parous women is not associated with any changes in the xeromammographic breast patterns as compared to parous controls. The changes described in hyperprolactinaemic patients can be understood in terms of their low oestrogenic activity.