bluuebunny/crossref_metadata_2025_split huggingface dataset:
EFFECT OF D-Trp6-LH-RH ON THE PITUITARY-GONADAL AXIS DURING THE LUTEAL PHASE IN THE BABOON
Authors: Hagino N. , Nakamoto O. , Kunz Y. , Arimura A. , Coy D. H. , Schally A. V. 
Published: December 2008

ABSTRACT
An effect of D-Trp6-LH-RH (superactive LH-RH agonist) in the pituitary and ovarian function was examined. Four regularly cycling baboons were used for this study. After determination of control values of plasma levels of LH, oestrogen and progesterone during the entire menstrual cycle, D-Trp6-LH-RH was infused subcutaneously for 7 days during the early luteal phase in these four baboons. An infusion of D-Trp6-LH-RH increased plasma LH and oestrogen, but it failed to alter the plasma level of progesterone. From these results, it seems unlikely that 1) D-Trp6-LH-RH has a luteolytic effect, and 2) an increased ovarian oestrogen causes luteolysis in the baboon.
SUPPRESSION OF THE TSH RESPONSE TO TRH BY THYROXINE THERAPY IN DIFFERENTIATED THYROID CARCINOMA PATIENTS
Authors: Lamberg B.-A. , Rantanen Marja , Saarinen Pirkko , Liewendahl K. , Sivula A. 
Published: December 2008

ABSTRACT
Absent response of serum thyrotrophin (TSH) after stimulation with 200 μg synthetic thyrotrophin-releasing hormone (TRH) was used as a criterion of adequate suppression of TSH secretion in the treatment of thyroid carcinoma patients with thyroxine. The mean causing total suppression of the response was 223 μg of thyroxine per day. At this dose level about 40 % of the patients had serum thyroxine concentrations above the upper reference interval and only 10 % had elevated triiodothyronine concentrations. In some patients the TSH response to TRH varied between absent and low normal when tested at long intervals. The ideal dose of thyroxine is obviously slightly higher than the smallest one causing total suppression of the TSH response to TRH, i.e. about 250 μg a day. The individual dose must be found using the TRH stimulation test because serum thyroid hormone levels cannot be used as a guideline for adequate dosage. In some patients the thyroid remnant of apparently normal thyroid tissue was not totally suppressed although the thyroxine dose was definitely above the level causing suppression of the response to TRH.
ENHANCED TSH STIMULATING EFFECT OF TRH BY SULPIRIDE IN MAN
Authors: Zanoboni Alberto , Zanoboni-Muciaccia Wanda , Zanussi Carlo 
Published: December 2008

ABSTRACT
Sulpiride, a specific dopaminergic blocker, was administered im to 6 normal male volunteers (100 mg) alone or in association with L-DOPA (500 mg per os, 90 min before sulpiride) or with TRH (400 μg iv in bolus, 30 min after sulpiride) and blood samples were obtained for TSH radioimmunoassay at various intervals before and after the treatments. Sulpiride alone produced a slight increase of plasma TSH levels which was inhibited by L-DOPA pre-treatment. The previous administration of sulpiride resulted in a marked increase of the TSH response to TRH. It is suggested that dopamine and TRH may interact to modulate pituitary secretion of both TSH and prolactin, though the hypophyseal thyrotrophs and lactotrophs show a different sensitivity to the common stimulatory and inhibitory substances.
IN VIVO ANDROGEN BINDING IN RAT SKELETAL AND PERINEAL MUSCLES
Authors: Dionne France T. , Dubé Jean Y. , Lesage Renée L. , Tremblay Roland R. 
Published: December 2008

ABSTRACT
In vivo binding of [3H] testosterone2), [3H]5α-dihydrotestosterone and [3H]3α-androstanediol to cytosolic and nuclear fractions of LA/BC and thigh muscles has been studied in functionally hepatectomized castrated rats following a 1 h infusion of the labelled steroid. The identification of metabolites formed from each steroid has also been determined in tissue cytosols. In each experiment, ventral prostate was used as reference target tissue.
After [3H] testosterone and [3H]5α-dihydrotestosterone perfusions, cytosolic binding could be demonstrated in a 8–10S peak on sucrose gradient with LA/BC and ventral prostate or in the macromolecular fraction after filtration through Sephadex G-25 with thigh muscles. In both types of muscles, [3H]5α-dihydrotestosterone binding represented only one tenth of [3H] testosterone binding. This behaviour seems to be related to the high rate of 5α-dihydrotestosterone metabolism observed in these tissues; testosterone, on the contrary, was not metabolized. After [3H]3α-androstanediol perfusion, cytosolic [3H] androgen binding in LA/BC and in thigh muscles was almost non-existent. In muscles [3H]3α-androstanediol remained essentially unconverted. In ventral prostate, with every hormone studied level of cytosolic binding was comparable. It was observed that in this tissue [3H] testosterone and [3H]3α-androstanediol were metabolized into [3H]5α-dihydrotestosterone.
Androgen binding to 0.4 m KCl extracted nuclear proteins has been demonstrated in ventral prostate as a 3.5–4.5S binding peak on sucrose gradient and this with each steroid perfused. In LA/BC, only [3H] testosterone gave a well defined binding peak. In thigh muscles, levels of nuclear binding were too low to be determined.
In summary, these results suggest that rat perineal and skeletal muscles possess cytosolic androgen binding proteins similar to those found in ventral prostate. However, it appears that steroid metabolism is quite different in ventral prostate and muscles with respect to presence of 5α-reductase activity and extent of conversion of 5α-dihydrotestosterone into androstanediols. These differences may explain why, in vivo, muscles bind testosterone instead of 5α-dihydrotestosterone as in ventral prostate.
LIGHT-INDUCED RHYTHMS OF PROLACTIN SECRETION IN THE RAM AND THE EFFECT OF CRANIAL SYMPATHECTOMY
Authors: Lincoln G. A. 
Published: December 2008

ABSTRACT
Four Soay rams cranially sympathectomised by removal of the superior cervical ganglia were housed alongside 4 control rams in an artificial lighting regime of alternating 16 week periods of short days (8L: 16D) and long days (16L: 8D) for 2 years. The variations in the plasma prolactin concentration revealed that while the control animals adjusted both the short term (diurnal) and long term (seasonal) rhythms in prolactin secretion in response to the changes in daylength, the ganglionectomised rams failed to respond. These sympathectomised animals continued to show long term changes in the circulating level of prolactin however and during the periods of hypersecretion a conspicuous diurnal rhythm in the hormone concentration was apparent.
CHLORPROMAZINE INHIBITS EPISODIC GROWTH HORMONE SECRETION IN THE RAT
Authors: Wakabayashi Ichiji , Kanda Megumi , Miki Nobuyasu , Demura Reiko , Shizume Kazuo 
Published: December 2008

ABSTRACT
Effects of chlorpromazine (CPZ) on plasma GH and prolactin levels were observed in conscious rats provided with chronic indwelling right atrial cannulae. The administration of CPZ (200 μg/100 g b.w. iv) suppressed episodic plasma GH burst and resulted in significant elevations of plasma prolactin levels.
These were also observed in rats in which two types of hypothalamic deafferentation, i.e. anterior and complete, had been carried out. The data suggest that CPZ acts within the medial basal hypothalamus and inhibits episodic plasma GH secretion. In addition, it is inferred that catecholamines are involved in the generation of episodic plasma GH burst.
THE USE OF REGION SPECIFIC RADIOIMMUNOASSAYS FOR CHARACTERIZATION OF CIRCULATING CALCITONIN IN PATIENTS WITH MEDULLARY CARCINOMA OF THE THYROID GLAND
Authors: Myhre Lisbeth , Gautvik Kaare M. 
Published: December 2008

ABSTRACT
Two antisera with known region specificities have been used to characterize calcitonin immunoreactivity (iCT) in serum of patients with medullary thyroid carcinoma (MCT). Antiserum I which was raised against the synthetic hormone (1–32 amino acid residues), contained heterogeneous populations of immunoglobulins directed predominantly against carboxyterminal sequences of the hormone, but the antiserum reacted also with the amino-terminal fragment (1–10 amino acid residues). Antiserum II, which was raised against the carboxy-terminal hormone fragment (11–32 amino acid residues) reached equally well with the intact hormone and the C-terminal fragment, but showed negligible binding of the amino terminal fragment. Antiserum I measured therefore both amino-terminal and carboxy-terminal sequences of calcitonin while antiserum II measured only carboxy-terminal amino acid sequences.
In 40 patients with MCT, antiserum I measured usually the highest concentration of serum iCT suggesting the presence of non-uniform hormone immunoreactivity. The different molecular forms of circulating iCT in 7 MCT patients were explored by using antiserum I after gel filtration on Sephadex G-100. The patients who were selected on basis of iCT measurement in serum using antiserum I and II, could be divided into 3 groups which showed characteristic iCT profiles. Group 1, in which antiserum II measured a higher concentration of serum iCT, contained predominantly (60–70 %) small fragments of calcitonin immunoreactivity. On the other hand, in the sera of group 3 in which antisera I measured an equal or the highest concentrations, the dominant form of the hormone consisted of molecular sequences equal to or larger than the intact hormone (90 %). In group 2, the two antisera measured an equal amount of serum iCT and molecular forms consisting mostly of larger hormone fragments dominated (50 %). All the patients were normocalcaemic in spite of frequently grossly elevated serum iCT, and 33 out of 36 patients had normal serum immunoreactive parathyroid hormone. In conclusion: 1. Serum iCT is heterogeneous and represents peptides of quite different molecular size with no or low biological activity. 2. Most of the serum calcitonin immunoreactivity consists of peptides with carboxy-terminal amino acid sequences. 3. Most, if not all, of the amino-terminal calcitonin immunoreactivity is due to monomeric and polymeric hormonal forms.
EFFECT OF PTU ADDED TO A LOW IODINE DIET ON PEROXIDASE ACTIVITY AND OTHER PARAMETERS OF THYROID FUNCTION IN RATS
Authors: Fragu P. , Othman S. Ben , Nataf B. M. 
Published: December 2008

ABSTRACT
The evolution of peroxidase activity was followed in relation to other parameters of thyroid function in rats when PTU was added to a low iodine diet (LID).
Ten days of PTU treatment brings about an equivalent increase in thyroid weight and iodide peroxidase activity at whatever time PTU was added to LID (10, 35, 54 and 80 days). It is shown that the effect of PTU treatment on thyroid weight and peroxidase activity is proportionately higher when PTU is added after 10 days of LID alone than after 80 days. The effect of various durations of PTU treatment was studied more closely when the addition began on day 10 of LID. On day 1 after addition of PTU thyroid weight increased significantly and no significant change was found in peroxidase activity. In contrast 5 days of PTU induced a significant elevation in enzymatic activity which is greater than that of thyroid weight. For a longer period of PTU treatment (10 days or more), the per cent increase of thyroid weight and peroxidase activity evolved parallely.
Already on day 1 of PTU treatment very rapid change were noted on T4, T3 and TSH levels; there was a decrease in T3 level (26 ± 5.6 %), while an increase in T4 level (26.4 ± 4.7 %) and TSH level (30 ± 5 %) was observed when the iodine content was still high (about 11 μg/thyroid gland). Thereafter T3 and T4 decreased and stayed at the same level after 10 days of PTU, while TSH increased rapidly and reached a plateau between 18 and 35 days. When PTU was added to LID treatment the increase in TSH was mostly due to a decrease of T3. The per cent increase in serum TSH level is always higher than that of thyroid peroxidase activity.
STUDIES ON THE ORIGIN OF ALTERED THYROID HORMONE LEVELS IN THE BLOOD OF RATS DURING COLD EXPOSURE
Authors: van Hardeveld C. , Zuidwijk M. J. , Kassenaar A. A. H. 
Published: December 2008

ABSTRACT
The effect of sympathetic activity on T4 and T3 levels in cold-exposed rats was investigated. Administration of the highest dose of propranolol (2 mg/100 g b.w.) twice daily during 4 days decreased T4 and T3 concentrations in plasma of rats living at 23°C (T4 from 46.4 ± 2.6 to 25.8 ± 5.3 nmol/l and T3 from 1.08. ± 0.6 to 0.82 ± 0.12 nmol/l). No significant effect on T4 and T3 levels (49.0 ± 11.6 and 1.48 ± 0.16 n/mol, respectively) after the administration of the same dose regimen of propranolol was observed in rats exposed to cold for 4 weeks. T4 and T3 levels in rats exposed to cold for 4 weeks were not significantly altered 1 week after sympathectomy, while remaining in the cold. However, chemical sympathectomy before cold exposure delayed the cold induced T3 elevation occurring during the first week of cold exposure (controls: from 1.16 ± 0.19 to 1.44 ± 0.29 nmol/l; sympathectomized rats: from 1.07 ± 0.12 to 1.17 ± 0.22 nmol/l). After 2 weeks of cold exposure the T3 levels of controls and sympathectomized rats were not significantly different (controls: 1.45 ± 0.12 nmol/l, sympathectomized rats: 1.38 ± 0.15 nmol/l). No effect of sympathectomy was observed on T4 levels.
These experiments show that the role of sympathetic activity in increasing T3 is not clear during cold exposure. They provide some evidence that sympathetic activity may play a role in the initiation of the process leading to increased T3 plasma levels during cold exposure.
STIMULATION OF (PRO-)INSULIN BIOSYNTHESIS AND RELEASE BY GASTRIC INHIBITORY POLYPEPTIDE IN ISOLATED ISLETS OF RAT PANCREAS
Authors: Schäfer R. , Schatz H. 
Published: December 2008

ABSTRACT
(Pro-)Insulin biosynthesis ([3H]leucine incorporation) and insulin secretion were studied in collagenase-isolated rat islets incubated for 3 hours at 1 and 2 mg/ml glucose in the presence of gastric inhibitory polypeptide (GIP). GIP augmented [3H]leucine incorporation and release of insulin at both glucose concentrations. In a second series of experiments it was found that an amino acid mixture was without influence on the insulotrophic action of GIP. Combined stimulation of insulin release by GIP and glucagon did not result in higher insulin output than observed in the presence of each substance alone.
Thus GIP, in contrast to many other gastrointestinal peptides, however similar to glucagon, enhances not only release but also biosynthesis of insulin. This insulinotrophic action can be observed already at a glucose concentration of 1 mg/ml. The results underline the outstanding role which GIP appears to play in the regulation of beta-cell function.
EFFECTS OF AN INTRAVENOUS INJECTION OF TETRACOSACTID ON PLASMA CORTICOSTEROID AND TESTOSTERONE LEVELS IN UNSTRESSED MALE RABBITS
Authors: Faulborn K. W. , Fenske M. , Pitzel L. , König A. 
Published: December 2008

ABSTRACT
Administration of tetracosactid into male rabbits, fitted with permanently indwelling jugular catheters, resulted in a rapid rise of plasma corticosteroids and plasma testosterone. Corticosteroid concentrations were significantly elevated at 40 and 60 min and testosterone concentrations 20 min after the iv injection of tetracosactid (2.5, 5.0, and 10.0 μg/kg body weight), in comparison to pre-treatment levels. Corticosteroid values in plasma were elevated as long as 120 min after tetracosactid injection. In contrast, testosterone levels were lower at 60–120 min after tetracosactid injection than corresponding pre-treatment values. However, these differences were not significant. At the doses used no tetracosactiddose-dependent corticosteroid or testosterone release could be found; apparently, testosterone release is only dependent upon basal plasma levels but not upon the dose of tetracosactid applied. From these studies it is concluded that tetracosactid may bring about an increase or decrease of testosterone concentration in plasma in the buck depending upon the length of time elapsing between injection of tetracosactid and blood withdrawal.
A PITFALL IN THE OVARIAN ASCORBIC ACID DEPLETION ASSAY (OAAD): EFFECT OF UNILATERAL OVARIECTOMY, hCG AND ASIALO-hCG
Authors: Odink J. , Brand E. C. , Van Hall E. V. 
Published: December 2008

ABSTRACT
The estimation of the effect of desialylation on the biological activity of human chorionic gonadotrophin (hCG), as determined in the ovarian ascorbic acid depletion assay (OAAD), according to the modification in which the animals are used twice, appeared to be dependent on the assay conditions. Animals which received hCG in the first assay (OAAD-1) gave higher potency estimates for hCG and asialo-hCG in the second assay (OAAD-2) than rats which received asialo-hCG in OAAD-1. The results of the experiments indicate that the ovarian sensitivity for hCG and asialo-hCG is increased after administration of hCG and unilateral ovariectomy and decreased after administration of asialo-hCG.
NEUROTRANSMITTER REGULATION OF ARGININE VASOTOCIN RELEASE FROM RAT PINEAL GLANDS IN VITRO
Authors: Sartin J. L. , Bruot B. C. , Orts R. J. 
Published: December 2008

ABSTRACT
Studies were performed to determine the effects of neurotransmitters on arginine vasotocin (AVT) release in vitro. Rat pineal glands were incubated with 10−8m or 10−6m norepinephrine (NE), dopamine (DA), serotonin (5HT), and acetylcholine (ACH) for eight h after which the concentrations of AVT in the media were determined by radioimmunoassay. With the exception of ACH, none of the neurotransmitters had a significant effect on AVT release. ACH significantly (P < 0.05) elevated AVT release in vitro at the 10−6m concentration but not at the 10−8m concentration. The data indicate that ACH may play a role in the regulation of rat pineal gland secretion of AVT in vitro.
EFFECT OF THE ACUTE ADMINISTRATION OF HALOPERIDOL AND PIMOZIDE ON PLASMA GH LEVELS IN ACROMEGALY
Authors: Carmina E. , Lo Coco R. , Lanzara P. , Jannì A. 
Published: December 2008

ABSTRACT
In 11 untreated acromegalic patients the plasma GH levels were determined after the acute administration of bromocriptine, haloperidol, pimozide (only in 8 patients) and of placebo. A 50 % or more suppression of the basal GH levels was arbitrarily defined as a positive response. Six patients displayed a positive response to bromocriptine. Five patients displayed a negative response to bromocriptine. Of these, 4 responded to both antidopaminergic drugs.
We conclude that the acute administration of antidopaminergic drugs reduces the GH secretion in some bromocriptine-insensitive acromegalic patients. Therapeutical implications will require further studies.
ANGIOTENSIN II AND K CHALLENGE FOLLOWING PROLONGED ACTH ADMINISTRATION TO NORMAL SUBJECTS
Authors: Kraiem Z. , Rosenthal T. , Rotzak R. , Lunenfeld B. 
Published: December 2008

ABSTRACT
Twelve healthy male volunteers on a normal Na and K intake and ambulatory received ACTH (40 IU, im) twice daily for 5 days followed by 2 days of angiotensin II (5–13 ng/kg body weight/min for 60 min) or oral K citrate (30 mEq./h×3). A discordance in the aldosterone-stimulating and pressor responses of angiotensin II was unmasked with only the latter response being positive following ACTH-induced refractoriness. K loading was a much more potent natriuretic stimulus than angiotensin II treatment. In contrast to angiotensin II, K could selectively enhance aldosterone secretion by overcoming the inhibition in secretion of the mineralocorticoid induced by prolonged ACTH exposure.
POLY-MALEIC ACID ANHYDRIDE (PMA) COUPLED CORTISOL ANTIBODY IN ROUTINE DETERMINATION OF URINARY FREE CORTISOL
Authors: Nielsen Jan 
Published: December 2008

ABSTRACT
Antibodies against cortisol-21-hemisuccinate conjugated to bovine serum albumin was raised in rabbits and conjugated with poly-maleic acid anhydride. The conjugate was used in a solid phase radioimmunoassay to measure the urinary excretion of unconjugated cortisol.
Cortisol was extracted with methylene chloride, the extract purified by chromatography on Sephadex LH-20, and the cortisol content measured with the radioimmunoassay.
The intra-assay variation of the method was 6 per cent and the interassay variation 10 per cent.
In 95 normal adult persons the excretion of free cortisol was 11–70, mean 30 μg/24 h.
No sex or age difference was found.
In 8 children aged 7–14 years the excretion was 8–46 μg/24 h.
GONADOTROPHINS DURING SECOND TRIMESTER OF PREGNANCY: I. LH AND hCG LEVELS IN MATERNAL SERUM AND AMNIOTIC FLUID AND THEIR RELATIONSHIP TO THE SEX OF THE FOETUS
Authors: Dattatreyamurty B. , Sheth A. R. , Purandare T. V. , Companiwalla R. , Krishna U. 
Published: December 2008

ABSTRACT
Luteinizing hormone and chorionic gonadotrophin levels were selectively measured by using radioimmunoassays in 98 maternal sera and 116 amniotic fluid samples obtained during 10–20 weeks of pregnancy. Levels of hCG in serum were clearly high during 10–14 weeks and thereafter declined gradually. In contrast, serum concentrations of LH during 10–20 weeks were either unmeasurable (< 1 ng/ml) or lower than those observed during the luteal phase of the menstrual cycle suggesting a decreased responsiveness of pituitary and/or a higher clearance rate for LH during this period of pregnancy. Neither LH nor hCG levels in maternal sera showed significant differences between male and female foetus bearers. A striking similarity was observed between maternal serum and amniotic fluid hCG patterns, despite hCG levels in maternal sera being always higher (1.5–26.9 fold). On the other hand amniotic fluid concentrations of LH became elevated following 12 weeks of gestation while maternal serum LH continued to be at low levels until 20 weeks. Furthermore a sexual dichotomy was observed in amniotic fluid LH concentrations but not in hCG levels during 14–20 weeks of pregnancy, with significantly lower LH levels in male foetus bearers than in female foetus bearers. Of interest is the clear demarcation in LH levels at 16 weeks of gestation. This sequential pattern of change in the concentrations of amniotic fluid LH is similar to those patterns reported by other investigators for foetal serum and pituitary LH during 10–20 weeks of gestation suggesting that the foetus may be the source of the increased levels of LH in amniotic fluid following 12 weeks of pregnancy.