bluuebunny/crossref_metadata_2025_split huggingface dataset:
Desensitization of the pituitary gland induced in vivo by luteinizing hormone-releasing hormone (LRH) or by the LRH-analogue buserelin does not affect the autonomous secretion of luteinizing hormone and follicle stimulating hormone as observed in vitro
Authors: Schuiling G. A. , Moes H. , Koiter T. R. 
Published: December 2008

Abstract. Three-weeks ovariectomized rats were sc implanted with Alzet® osmotic minipumps which released either LRH or the LRH-analogue buserelin at the rate of 250 ng/h. Control rats were implanted with a silastic 'shampump'. After explantation, 6 days later, the pituitary glands of part of these rats were exposed to the maximally active LRH concentration of 1 μg/ml for a period of 6 h. using a perifusion system. In a second group of rats explantation and perifusion was done not directly, but 5 days after cessation of the I.RH pretreatment.
After 6 days in vivo pre-treatment with LRH or with buserelin the pituitary LH and FSH stores were partially depleted, the depletion after buserelin being stronger than after LRH. The pituitary glands of the first group of rats showed rates of both maximally LRH-stimulated and unstimulated (autonomous) LH- and FSH-secretion which were strongly impaired, the impairment after buserelin being stronger than after LRH. In the group with a 5 days interval between in vivo LRH/buserelin pre-treatment and explantation the pituitary LH and FSH stores were restored to the range of pre-treatment levels. Of these pituitaries the autonomous secretion of LH and FSH as well as the maximally LRH-stimulated secretion of FSH was restored to the normal level; the maximally LRH-stimulated secretion of LH, however, remained depressed, indicating that 5 days after cessation of exposure to LRH or to buserelin, and in spite of restored pituitary LH/FSH contents, the sensitivity of the LH releasing system to LRH was still subnormal.
The results suggest that the autonomous secretion of LH and FSH as well as the LRH-stimulated secretion of FSH, but not the LRH-stimulated secretion of LH may be dependent on the content of the pituitary LH and FSH stores. Furthermore, after treatment with LRH or buserelin the autonomous secretion of LH may return to a normal level when the sensitivity of the LH releasing system to LRH is still impaired: apparently, the mechanisms underlying the autonomous and the LRH-stimulated LH secretion do not influence each other.
It is discussed that in situations in which a complete suppression of the pituitary-gonadal axis is demanded (carcinomata of the breast or the prostate; precocious puberty) desensitization of the pituitary gland with super-active LRH-analogues like buserelin alone is not sufficient, as this does not affect the autonomous secretion of LH and FSH. For total suppression of gonadal activity the pituitary gland must be completely depleted with relatively large doses of analogue.
Interaction between catecholamines and prostaglandin F2α in human luteolysis
Authors: Bennegård Barbro , Dennefors Bo , Hamberger Lars 
Published: December 2008

Abstract. From each of 14 women undergoing laparotomy at different stages of the luteal phase of the cycle. the corpus luteum (CL) was excised, cut into pieces and incubated for 120 min. Incubations were performed in the absence and presence of hCG and prostaglandin F2α (PGF2α). In addition, noradrenaline (NA) was added to the incubation medium of newly formed CL, and the adrenergic blocker propranolol to incubated specimens of mid-luteal phase CL.
After incubation the tissue levels of protein and cyclic AMP (cAMP) and the media concentrations of progesterone (P) were determined.
In young CL, PGF2α did not interfere with the stimulatory effect of hCG on neither cAMP nor P formation, while in CL of the mid-luteal phase PGF2α significantly counteracted the stimulatory effect of hCG on these two parameters. In the presence of propranolol, however, this antigonadotrophic effect of PGF2α in vitro was abolished. Furthermore, when NA was added to specimens of young CL, PGF2α significantly counteracted the stimulatory effect of hCG on both cAMP and P formation.
These in vitro data show that endogenous catecholamines may regulate the antigonadotrophic, 'luteolytic' effect of PGF2α in human CL.
Effects of 1αOHD2 on bone tissue Studies of 1αOHD2 and 1αOHD3 in normal rats and in rats treated with prednisolone
Authors: Sjödén G. O.J. , Johnell O. , DeLuca H. F. , Lindgren J. U. 
Published: December 2008

Abstract. Three months old male rats were fed a diet containing 0.3% calcium and 0.5% phosphate. Prednisolone was added to the diet at a dose of 1.5 mg a day and the effect of oral treatment with 0.5 μg 1αOHD2 or 0.5 μg 1αOHD3 was studied.
After 6 weeks rats given prednisolone had a lower bone mass and bone density. The serum phosphate concentration was also lower.
Rats given 1αOHD3 had an increased serum calcium concentration even when simultaneously treated with prednisolone. 1αOHD2 did not cause hypercalcaemia.
The decrease in bone density caused by prednisolone was prevented by the administration of 1αOHD2. Rats receiving 1αOHD3 together with prednisolone still exhibited a lower bone density. Furthermore, 1αOHD3 decreased bone mass in normal rats and caused a higher mean value of osteoclasts/area whereas 1αOHD2 reduced the number of osteoclasts/area.
The study indicates that 1αOHD2 is an effective vitamin D analogue with a lower tendency to cause bone resorption.
Prolactin and growth hormone secretion in chickens: stimulation by histamine and inhibition by gamma-aminobutyric acid
Authors: Hall T. R. , Harvey S. , Chadwick A. 
Published: December 2008

Abstract. Anterior pituitary glands from chickens (Gallus domesticus) were incubated with or without single, mediobasal chicken hypothalami in medium containing histamine, alone or together with the antagonist diphenhydramine or in medium containing gamma-aminobutyric acid (GABA), alone or together with the antagonists bicuculline or picrotoxin. The release of prolactin (Prl) and growth hormone (GH) was measured by homologous radioimmunoassay.
Histamine had no direct effect on the release of either hormone but stimulated Prl (in a dose-related way) and GH release when anterior pituitary glands were co-incubated with hypothalami. Diphenhydramine also had no direct effect on Prl or GH secretion but blocked the stimulatory effect of histamine on hypothalamusinduced Prl and GH release.
When anterior pituitary glands were incubated without hypothalami, GABA, bicuculline and picrotoxin had no effect on the release of Prl or GH. However, GABA inhibited the release of both hormones in a concentration-related manner, when anterior pituitary glands were co-incubated with hypothalami. This inhibition was blocked by both bicuculline and picrotoxin.
These results suggest that histamine and GABA may be involved in controlling the secretion of Prl and GH from the avian pituitary gland, possibly by modifying the secretion of hypothalamic releasing and/or release-inhibiting hormones.
Pituitary-gonadal function in boys after high dose testosterone treatment for excessively tall stature
Authors: Brämswig J. H. , Nieschlag E. , Schellong G. 
Published: December 2008

Abstract. One hundred excessively tall boys with a height prediction of 205.32 ± 5.28 cm (mean ± sd) were treated with 500 mg testosterone oenanthate (TE) every 14 days for a period of 14.96 ± 5.29 months. Following therapy, the hypothalamo-pituitary-gonadal axis was evaluated, using a standardized GnRH-test at median time intervals of 14 days, 6 weeks, 13 weeks, 6 months and 16 months.
Basal and stimulated LH- and FSH-values were not measurable or severely suppressed in all boys 14 days after termination of therapy. Starting at 6 weeks, normalization of pituitary-gonadal function was demonstrated in 93 boys (group 1) with follow-up periods of up to 48 months.
Six boys (group 2) developed transitory hypergonadotrophic LH- and FSH-secretory patterns for up to 11 months after the last TE-injection. Testosterone and gonadotrophins were within the normal range in all 6 boys, when prospectively re-evaluated at 12 to 27 months after termination of therapy.
During TE-administration, testicular volume was reduced in some, and in most boys did not show the normal enlargement occurring during puberty. However, return to normal testicular size was seen several months after treatment.
The data suggest that no major functional alterations of the hypothalamo-pituitary-gonadal axis occur in pubertal boys after high-dose and long-term testosterone therapy for excessively tall stature.
Effects of long-term treatment with thyroxine on pituitary TSH secretion and heart action in patients with hypothyroidism
Authors: Yamauchi Keishi , Takasu Nobuyuki , Ichikawa Kazuo , Yamada Takashi , Aizawa Toru 
Published: December 2008

Abstract. The effects of thyroxine (T4) treatment on pituitary thyrotroph cells and on the heart were studied in 68 female patients with hypothyroidism. During the initial 12 months of T4 treatment, relatively small doses of T4 (1.3 μg/kg) normalized serum T4, triiodothyronine (T3), TSH and lipid concentrations in mild hypothyroidism, while moderate doses of T4 (1.7–2.0 μg/kg) normalized serum T4, T3 and lipid concentrations but not serum TSH levels or the volume of sella turcica in moderate and severe hypothyroidism; however, serum TSH levels and the volume of sella turcica returned to normal with continuation of these doses of T4.
Systolic time intervals (ET/PEP) can discriminate between euthyroid and hyperthyroid states and agree well with serum TSH levels. However, ET/PEP was unequivocally elevated in about 40% of treated hypothyroid patients with normal serum T3, T4 and TSH levels which had been maintained over 48–54 months. Since the reciprocal relationship between free T4 and TSH levels was maintained in all treated patients, elevated ET/PEP with normal TSH levels indicates that the heart is more sensitive to thyroid hormones than the pituitary thyrotroph in 40% of treated hypothyroid patients.
During T4 treatment in patients with hypothyroidism, ET/PEP should be followed and T4 doses adjusted to maintain normal ET/PEP rather than normal serum TSH levels, especially in older patients in whom T4 may aggravate angina pectoris or provoke myocardial infarction.
Demonstration and characterization of immunoreactive methionine-enkephalin, leucine-enkephalin, methionine-enkephalin-Arg6-Gly7-Leu8 and methionine-enkephalin-Arg6-Phe7 in human phaeochromocytoma
Authors: Youshimasa Takaaki , Nakao Kazuwa , Sakamoto Makoto , Suda Mitsuaki , Morii Narito , Ikeda Yoshio , Ishihara Takashi , Manno Masataka , Hamada Satoshi , Shimbo Shinichiro , Mori Toru , Yoshimi Teruya , Matsukura Shigeru , Imura Hiroo 
Published: December 2008

Abstract. To elucidate whether or not human phaeochromocytoma contains methionine-enkephalin-Arg6-Gly7-Leu8 (Met-enkephalin-Arg-Gly-Leu) and methionine-enkephalin-Arg6-Phe7 (Met-enkephalin-Arg-Phe) together with methionine-enkephalin (Met-enkephalin) and leucine-enkephalin (Leu-enkephalin), all of which are known to exist in the same precursor molecule (preproenkephalin A), we examined extracts from 16 phaeochromocytomas using high performance liquid chromatography (HPLC) and gel exclusion chromatography coupled with radioimmunoassays (RIAs) for these four opioid peptides. Met-enkephalin-Arg-Gly-Leu-like immunoreactivity (-LI) and Met-enkephalin-Arg-Phe-LI existed together with Met-enkephalin-LI and Leu-enkephalin-LI in 16 phaeochromocytomas. There was a wide variation in contents of Met-enkephalin-LI, Leu-enkephalin-LI, Met-enkephalin-Arg-Gly-Leu-LI and Met-enkephalin-Arg-Phe-LI. Significant positive correlations were observed among the contents of these four opioid peptides in 16 phaeochromocytomas. HPLC and gel exclusion chromatography followed by the RIAs showed the presence of Met-enkephalin, Leu-enkephalin, Met-enkephalin-Arg-Gly-Leu and Met-enkephalin-Arg-Phe together with their high molecular weight forms, which existed in variable amounts. Molar ratios of the contents of these four opioid peptides determined after HPLC varies from case to case.
These results indicate the co-existence of Met-enkephalin, Leu-enkephalin, Met-enkephalin-Arg-Gly-Leu and Met-enkephalin-Arg-Phe in human phaeochromocytomas, suggesting the preservation of amino acid sequences of these four opioid peptides even in neoplastic tissues. Evidence for some abnormalities in the posttranslational processing of preproenkephalin A to these four opioid peptides was obtained in certain phaeochromocytomas.
Cyclophenil, a non-steroidal compound with a higher central than peripheral oestrogenic activity: study of its effects on uterine growth and on some central parameters in castrated female rats
Authors: Celotti F. , Avogadri N. , Melcangi R. C. , Milani S. , Negri-Cesi P. 
Published: December 2008

Abstract. The oestrogenic activity of cyclophenil, a non-steroidal compound which has structural analogies with both stilbene and triphenylethylene, has been reevaluated utilizing both central and peripheral parameters. The central parameters considered were LH, FSH, prolactin secretion and two enzymatic systems known to be oestrogen-sensitive: hypophyseal 5α-reductase and hypothalamic aromatase. The uterine growth test was used to determine oestrogenic peripheral activity.
The compound was administered at various doses in comparison with oestradiol benzoate (EB) to long-term castrated female rats.
Cyclophenil has an activity 1/8110 times that of EB on uterine growth, and 1/1660 and 1/550 times that of EB in inhibiting LH and FSH. respectively. The hypophyseal 5α-reductase(expressed as DHT formation) was inhibited 1710 times less by cyclophenil than by EB. The other parameters considered were unsuitable to provide a statistically reliable estimate of the potency ratios between the two compounds.
The data show that cyclophenil is an oestrogenic compound with peculiar characteristics. This substance is more effective in expressing its oestrogenic activity in central structures than in the peripheral ones.
Successful treatment with sodium valproate of a patient with Cushing's disease and gross enlargement of the pituitary
Authors: Koppeschaar Hans P. F. , Croughs Ronald J. M. , van 't Verlaat Johanna W. , Hendriks Martin J. , Arts Cor J. M. , Thijssen Jos H. H. , Schwarz Frits 
Published: December 2008

Abstract. Transfrontal hypophysectomy was performed in a patient with Cushing's disease and gross enlargement of the pituitary. Despite some reduction of cortisol production active Cushing's syndrome remained due to the presence of a tumour remnant. Medical treatment with the GABA-transaminase inhibitor sodium valproate induced hypocorticism necessitating corticosteroid substitution therapy. Nine months after sodium valproate withdrawal hypercorticism was documented. Re-institution of sodium valproate treatment induced hypocorticism again.
As sodium valproate is known to induce a decrease of plasma ACTH in Nelson's syndrome, it is proposed that large tumours present at the time of diagnosis and those appearing after adrenalectomy may represent the spectrum of a single disorder. A prospective trial to study the effects of sodium valproate and other neurotransmitter modulating agents on the size and endocrine function of ACTH secreting macroadenomas is urgently needed.
Thyroid stimulating immunoglobulins in Graves' disease with goitre growth, low thyroxine and increasing triiodothyronine during PTU treatment
Authors: Hegedüs Laszlo , Hansen Jens M. , Bech Karine , Kampmann Jens P. , Jensen Keld , Andersen Elo , Hansen Palle , Karstrup Steen , Bliddal Henning 
Published: December 2008

Abstract. In 50 consecutive patients with Graves' disease treated with PTU, 7 (group 1) developed increasing goitre in spite of unmeasurable TSH. Thyroid variables were compared with those from 10 controls with an ordinary response to PTU (group 2). Serum T4 decreased in group 1 from 246 ± 47 nmol/l (mean ± sd) to 40 ± 9 nmol/l after 6 weeks of PTU treatment and continued to be below the normal range during the next 4 months. In group 2 serum T4 decreased from 190 ± 35 to 88 ± 47 nmol/l and stayed in the normal range. Serum T3 was normalized in both groups after 6 weeks but increased to values above the normal range in group 1 after that time. In spite of unmeasurable TSH during the 6 months of treatment in group 1, thyroid volume, determined ultrasonically, increased significantly from 60 ± 29 to 93 ± 68 ml (P < 0.05), but was unaltered in group 2 about 25 ml.
Thyroid stimulating antibodies (TSAb) measured by adenylate cyclase activation (normal below 109%) decreased in group 2 from 117 ± 23 to 90 ± 17% (P <0.01) (6 months of therapy), but increased significantly in group 1, from 201 ± 47% to a maximum value of 234 ± 69% (P < 0.05). TSH binding inhibitory immunoglobulins (TBII) (given as per cent inhibition, normal below 26%) decreased in group 2 from 43 ± 29 to 29 ± 27% (P < 0.05) but were unaltered high in group 1,66 ± 25% before therapy and 57 ± 26% after 6 months of therapy. A positive correlation was found between thyroid volume and TSAb and TBII levels (P < 0.05, P < 0.05) before treatment as well as during the treatment period of 6 months. In 5 of 7 patients of group 1 either 131I therapy or subtotal thyroidectomy were necessary to control the disease.
It is proposed that TSAb and TBII remaining abnormal in this subgroup of patients with Graves' disease, might in part explain the unusual response to PTU-treatment.
Impairment of adrenergic-induced proopiomelanocortin-related peptide release in heroin addicts
Authors: Facchinetti Fabio , Volpe Annibale , Nappi Giuseppe , Petraglia Felice , Genazzani Andrea R. 
Published: December 2008

Abstract. The effects of iv stimulation with clonidine on plasma levels of β-lipotropin (β-LPH), β-endorphin (β-EP), cortisol, growth hormone (GH) and adrenocorticotrophic hormone (ACTH) were tested in a group of 10 healthy volunteers and in 8 heroin abusers.
Hormones were measured either by direct radioimmunoassay (RIA) (GH, cortisol) or after plasma extraction and Sephadex G-75 column chromatography (β-LPH and β-EP) or by immunoradiometric assay (IRMA) (ACTH). Plasma levels of GH increased in a similar fashion in the two groups. In the controls, clonidine induced release of β-LPH and β-EP after 30 min (from 8.9 ± 1.0 to 19.1 ± 4.6 fmol/ml, P < 0.01 and from 8.1 ± 0.6 to 17.9 ± 4.6, P < 0.01) and of ACTH after 60 min (from 12.1 ± 1.8 to 18.1 ± 1.8, P < 0.05) while in addicts β-EP but not β-LPH showed a significant increase (from 8.5 ± 0.7 to 19.8 ± 4.2, P < 0.05), 90 min after the injection.
In heroin addicts, plasma cortisol levels decreased continuously after clonidine stimulation while in controls they showed a biphasic pattern, decreasing until the 60th min (from 135.2 ± 30.4 ng/ml to 74.0 ± 13.3, P < 0.05) and regaining basal levels 1 h later (122.0 ± 24.8, P < 0.05 vs 60th min value).
These data demonstrate the existence in human beings of noradrenergic control of proopiomelanocortin (POMC)-related peptides and indicate that chronic opiate abuse greatly interferes with this control.
Clonidine-induced release of plasma β-EP may be of importance with regard to its therapeutic effects in detoxification.
Hyperglycaemic effect of glucagon administered intracerebroventricularly in the rat
Authors: Marubashi Seijiro , Tominaga Makoto , Katagiri Tadashi , Yamatani Keiichi , Yawata Yoshikazu , Hara Masao , Sasaki Hideo 
Published: December 2008

Abstract. The intracerebroventricular (icv) administration of 100 ng glucagon resulted in more prolonged and pronounced elevations of plasma glucose levels than the intravenous injection of 100 ng glucagon. Insignificant changes in plasma IRI and IRG levels after icv glucagon administration contrasted to marked increases in both IRI and IRG levels after the iv injection.
Icv glucagon-induced hyperglycaemia was completely prevented by the prior administration of atropine, phentolamine or hexamethonium, and partially inhibited by bilateral adrenalectomy, but not by propranolol pretreatment. These findings suggested that the hyperglycaemic effect is brought about through cholinergic and α-adrenergic neural pathways and partly via the adrenal medulla.
Effect of iodide treatment on iodine concentration and volume of endemic non-toxic goitre in childhood
Authors: Leisner B. , Henrich B. , Knorr D. , Kantlehner R. 
Published: December 2008

Abstract. In a total of 195 children and adolescents of both sex (mean age 12.9, range 5–17 years) with endemic non-toxic goitre the thyroidal iodine concentration (IC) was determined using X-ray fluorescent scanning on admission and during iodine (100 μg daily) and l-thyroxine (3 μg/kg body weight daily) treatment respectively. Additionally the thyroid volume was measured sonographically in a longitudinal study including 46 patients before and after 4–8 months of iodine supplementation (100 μg daily).
The IC was 305 ± 144 μg/g. It compared well with that of adult goitre patients (288 ± 109 μg/g) and was significantly inferior to the value of normal controls (389 ± 170 μg/g). Under l-thyroxine therapy the IC further decreased (243 ± 144 μg/g), whereas patients receiving iodide showed an increase of the IC (570 ± 197 μg/g). The mean TSH level fell from 2.3 ± 0.9 μU/ml to 1.4 ± 0.6 μU/ml. The average T4/TBG (thyroxine binding globulin) ratio showed a slight increase which, however, was not significant.
The mean goitre volume decreased by 40%.
It was evidenced that iodide is useful not only in the prophylaxis of non-toxic goitre but also as a more physiologic treatment than thyroid hormones, at least for young subjects with simple diffuse goitres.
Prolonged ACTH infusion suppresses aldosterone secretion in spite of high renin activity
Authors: Oelkers W. , Harendt H. , Exner P. 
Published: December 2008

Abstract. Five normal young males on a low sodium diet received iv ACTH (1–24) infusions (10 IU/24 h) for 100 h in addition to diuretics. The aim of the study was to find out whether the biphasic effect of ACHT on aldosterone (initial stimulation followed by 'esacpe') could be prevented by keeping plasma renin activity (PRA) at a fairly constant high level. PRA was around 20 ng/kg/min before and towards the end of the ACTH infusion. Plasma aldosterone and aldosterone excretion rates were, nevertheless, only transiently stimulated, but the first was relatively more suppressed than the latter at the end of the ACTH infusion. Plasma 18-OH-corticosterone followed the same pattern. Even on the last infusion day, aldosterone and 18-OH-corticosterone levels were still higher than in normal ambulatory sodium-replete men. The fasciculata steroids cortisol, 11-deoxycorticosterone and corticosterone were continuously stimulated by ACTH.
It is concluded that the biphasic response of zona glomerulosa steroids to ACTH is basically independent of renin and angiotensin II. However, the marked suppression of aldosterone secretion observed in sodium-replete individuals during prolonged ACTH treatment was not seen in this study. Angiotensin II or a different factor associated with sodium depletion may, therefore, partly protect the zona glomerulosa from adverse effects of ACTH observed in the sodium-repelete state.