bluuebunny/crossref_metadata_2025 huggingface dataset:
BIOLOGICALLY ACTIVE LUTEINIZING HORMONE (LH) IN PLASMA
Authors: Rajalakshmi M. , Robertson D. M. , Choi S. K. , Diczfalusy E.
Published: December 2008

An in vitro bioassay method for measuring LH activity was applied to male plasma. This method is based on the specific testosterone response to LH activity by interstitial cells from mouse testes. In contrast to assays conducted on female plasma, non-parallel response lines were obtained between serial dilutions of untreated male plasma and the International Reference Preparation for Human Pituitary Gonadotrophins (FSH and LH/ICSH) for bioassay (code no. 69/104). In an attempt to eliminate this source of error, which would invalidate the assays, plasma was subjected to either ether extraction or charcoal adsorption prior to assay. While ether extraction was ineffective, charcoal treatment eliminated the source of non-parallelism. Evidence is presented indicating that the inclusion of a charcoal pre-treatment step provides an assay method for LH which fulfils the recognized criteria of reliability when applied to male plasma.

An investigation of the likely causes of non-parallelism was undertaken by incubating mouse interstitial cells with various steroids and steroid sulphates at concentrations likely to be present in plasma. While most of the presumed precursors of testosterone were converted to testosterone, steroid sulphates (dehydroepiandrosterone sulphate and pregnenolone sulphate) at high concentrations as present in male plasma were the most active compounds in forming testosterone. However, the amount of testosterone produced from these precursors under controlled conditions was insufficient to account entirely for the deviation from parallelism observed with male plasma. Hence, the non-parallelism observed with untreated plasma samples cannot be entirely explained by the presence of steroidal testosterone precursors in male plasma.
REDUCED UPTAKE OF OESTRONE AND CORTICOSTERONE BY CELLS FROM CIRRHOTIC RAT LIVER
Authors: Rao Marie Luise , Rao Govind S. , Höller Michael , Breuer Heinz
Published: December 2008

The uptake of oestrone and corticosterone into isolated parenchymal cells from normal and cirrhotic rat livers has been studied. The maximal uptake of both hormones by cells from cirrhotic livers was reduced by 30 to 50 % compared to the uptake by normal cells. The affinity of the uptake systems for both hormones was similar in cells from normal and cirrhotic livers.

The activation energy for the uptake of oestrone by normal cells was 3.9 ± 0.2 kcal./mol from 0 to 40°C, whereas that for the uptake of oestrone by cells from cirrhotic rats was 3.0 ± 0.1 kcal./mol. Glucuronidation of oestrone by cells from cirrhotic livers was lower than that by cells from normal livers, but that by homogenates of the diseased tissue was not affected.

The Arrhenius plot of the uptake of corticosterone by normal cells showed a transition at 17°C; the activation energy for the uptake by normal cells was 16.0 ± 1.4 and 6.0 ± 0.7 kcal./mol from 0 to 17°C and 17 to 40°C, respectively. The activation energy for the uptake of corticosterone by cells from cirrhotic livers was 11.4 ±0.6 and 2.8 ± 0.2 kcal./mol from 0 to 17°C and 17 to 40°C, respectively. Sulfhydryl reagents reduced the uptake of both hormones by both cell preparations by 10 to 20 %; treatment of cells with β-galactosidase, phospholipase A and pronase reduced the uptake of both hormones. The results suggest that the amount of oestrone and corticosterone transported into isolated parenchymal cells from cirrhotic livers is decreased.
HIGH CORTICOSTEROID LEVELS IN PLASMA OF ADULT AND FOETAL WEDDELL SEALS (LEPTONYCHOTES WEDDELLI)
Authors: Liggins G. C. , France J. T. , Knox B. S. , Zapol W. M.
Published: December 2008

Pregnant and non-pregnant Weddell seals and foetuses were found to have very high plasma concentrations of corticosteroids (1–7 μmol/l) that were unaffected by stress. Cortisol comprised most of the corticosteroid in the adult but only 50 % of that in the foetus. The affinity constant (4.30–5.53 × 107 l/mol) and specificity of CBG and the MCR (4.5 l/d/kg lean body mass) in adult seals were similar to those of Man. The binding capacity of CBG (1.48–1.86 μmol/l) which is approximately three times that of Man contributed to the high plasma corticosteroid concentrations but the main factor was the cortisol turnover rate of 3670 μmol/d (1.3 g/d) which is the highest value reported in any species.
PROGESTERONE-INDEPENDENT AVIDIN INDUCTION IN CHICK TISSUES CAUSED BY TISSUE INJURY AND INFLAMMATION
Authors: Elo Heikki A. , Kulomaa Markku S. , Tuohimaa Pentti J.
Published: December 2008

Progesterone was administered to oestrogen-treated and untreated chicks, or inflammation in the abdominal cavity was caused by intestine and liver injury or intraperitoneal actinomycin D administration. Local injury to the pectoral muscle was also carried out. Chicks were killed 24–26 h after the treatment and the biotin-binding egg white protein, avidin, was assayed in a number of tissues using a [14C] biotin-binding method and radioimmunoassay. Ovalbumin was also assayed with a radioimmunoassay. Avidin was not found in the tissues of control chicks. Progesterone induced avidin only in the oviducts of oestrogen-treated chicks. After intestine and liver injury avidin was found, however, in all the tissues of oestrogen-treated and untreated chicks studied except for the brain. The concentrations were highest in the oviduct, lung, intestine and bursa of Fabricius. Actinomycin D (200 μg/kg) caused ascites and subcutaneous oedema in 40–60 % of the chicks, and avidin was found only in the tissues of these inflamed animals. Avidin production caused by the local muscular injury was restricted to the injured area. Tissue injury and inflammation did not induce ovalbumin in any tissue.

The study shows that avidin can be induced besides the oviduct also in non-oviductal chick tissues, and it is proposed that there are both progesterone-dependent and -independent avidin induction mechanisms.
EVALUATION OF THE GONADOTROPHIC RESPONSIVENESS OF THE PITUITARY TO ACUTE AND PROLONGED ADMINISTRATION OF LH/FSH-RELEASING HORMONE (LH-RH) IN NORMAL FEMALES AND MALES
Authors: Pinto Heidi , Wajchenberg Bernardo Leo , Lima Fabio Bessa , Goldman Jayme , Comaru-Schally Ana Maria , Schally Andrew V.
Published: December 2008

In normal females, the injection of 25 μg of LH-RH (acute test) induced a greater LH and FSH release from the pituitary in the mid-luteal than in the mid-follicular phase of the menstrual cycle. In normal males, the responsiveness to 25 μg LH-RH was greater than that in females at mid-follicular but not at the luteal stage. The pituitary response to the prolonged LH-RH infusion (0.21 μg/min/8 h) was similar in both phases of the cycle of the females with a decline in serum gonadotrophins after the 4th hour and was paralleled by a significant increase of plasma oestradiol levels. In males the LH, but not the FSH secretion was lower as compared to female subjects, and gonadotrophin levels did not show a fall during the infusion. The acute injection of 25 μg LH-RH at the end of a prolonged infusion induced the same response in the female subjects in both phases of the cycle. In males, the acute test following prolonged infusion produced a similar LH secretion, but a lower FSH response than in females. The comparison of the acute test alone and that preceded by a prolonged LH-RH infusion, demonstrated that, in females, the only significant differences consisted of a greater LH secretion in the former test in the mid-luteal phase. In males there was greater FSH secretion in the acute isolated test than when this test was given after the prolonged infusion.
GROWTH IMPAIRMENT WITH ELEVATED SOMATOMEDIN LEVELS IN CHILDREN WITH CHRONIC RENAL INSUFFICIENCY
Authors: Spencer E. Martin , Uthne K. O. , Arnold W. C.
Published: December 2008

In children with chronic renal insufficiency serum levels of somatomedin measured by radioreceptor assay were found to be strikingly elevated and were in the same range as in acromegaly in spite of decreased growth. The serum somatomedin level was inversely correlated with renal function and children on haemodialysis had the highest values. The elevated somatomedin was most likely due to progressive destruction of the kidney, the primary catabolic site for somatomedin and other polypeptides. After successful transplantation the somatomedin values fell to slightly above normal even though growth was still impaired. Using a bioassay based on the mitogenic property of somatomedin, a lower than normal rather than an increased level was found in chronic renal insufficiency suggesting that in uraemia an inhibitor to somatomedin bioactivity was present. It is concluded that the cause of the growth failure in chronic renal insufficiency and after transplantation is not due to a lack of somatomedin, but an inhibitor to its action could be a factor. It would appear that a normal somatomedin may be necessary for normal growth, but it is not sufficient.
TRANSDUCER PROBE FOR THE MEASUREMENT OF OESTRADIOL-INDUCED CHANGES IN THE VAGINA OF OVARIECTOMIZED EWES
Authors: Borth Rudi , Benoit Henry J. , Woolever C. Allan
Published: December 2008

A modified non-invasive vaginal probe, using electronic transducers to monitor six physical variables reflecting vaginal changes, was tested in oophorectomized ewes according to a Latin-Square design allocating six treatments to six animals in a balanced time sequence. The transducers measured thermal conductance, temperature near the cervix and near the vulva, and light reflectance at 900, 660, and 565 nm. The treatments included four iv doses of oestradiol-17β (0.5, 5.0, 50, and 500 μg per 50 kg body weight) and two controls (injection vehicle, and no injection). Despite large residual variation, the results (1) show that the higher oestradiol doses produced responses of all six variables; (2) suggest improvements in future probe design; and (3) raise interesting questions on dose-response relationships deserving further study.
ENDOCRINE STUDIES AND SUCCESSFUL TREATMENT IN A PATIENT WITH TRUE HERMAPHRODITISM
Authors: Valdés Evangelina , Fernández del Castillo Carlos , Gutiérrez Raul , Larrea Fernando , Medina Martha , Pérez-Palacios Gregorio
Published: December 2008

A 12-year old, 46 XX true hermaphrodite born with genital ambiguity was studied and successfully treated. The serum LH and FSH profile resembled that of a pubertal normal individual, and LH-RH administration induced a normal LH response. Baseline testosterone serum levels were within the range for normal children. Exogenous HCG stimulation induced a significant serum testosterone increase up to values similar to those observed in normal post-pubertal males. Surgical examination disclosed the presence of bilateral ovotestis, normal Mullerian derivatives, epididymis, and vas deferens. A complete ovotestis with testicular predominance and the testicular portion of the contralateral ovotestis as well as the Wolffian derivatives, were removed. A further HCG stimulation 3 months after surgery, failed to induce serum testosterone increase. Spontaneous menarche was observed 6 months after surgery and ovulation was well documented. At present the patient has several characteristics of female sex including those of chromosome complement, gonad, internal and external genitalia, hormone levels and gender identity, thus demonstrating that treatment was successful and that reproductive function could be obtained. The finding of spontaneous ovulation following removal of the testicular portion suggests normal cyclic gonadotrophic release implying a difference between animal models and man in regard to hypothalamic virilization.
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

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

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

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

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

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

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

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

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

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

(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

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

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

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

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

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

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

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.
STUDIES ON OXYTOCIN IN THE BABOON DURING PREGNANCY AND DELIVERY
Authors: Dawood M. Yusoff , Lauersen Niels H. , Trivedi Devendra , Ylikorkala Olavi , Fuchs Fritz
Published: December 2008

Oxytocin was determined by radioimmunoassay in pregnant baboons throughout gestation, in the foetus at caesarean section, and after oxytocin infusion into the mother and foetus. Serial maternal plasma oxytocin in 6 baboons during pregnancy showed a significant correlation between the gestational age and maternal plasma oxytocin concentrations with a correlation coefficient of r = 0.3185 and P < 0.005. Seventy-one out of 75 plasma samples (94.7 %) during pregnancy had detectable levels of oxytocin. Uterine vein plasma had higher oxytocin concentrations than maternal plasma and amniotic fluid (18.6 ± 4.6 pg/ml; mean ± se) but lower than umbilical, jugular vein and cardiac blood from the foetus. Foetal pituitary gland contained 5.4–26.1 μg oxytocin/g. Regular uterine contractions were established with iv oxytocin of 4–20 mU/min and the plasma oxytocin measured showed a significant correlation with the uterine activity achieved (r = 0.64, P < 0.001). The disappearance of plasma oxytocin at 179 days gestation gave an apparent half-life of 1.1 and 1.7 min in 2 baboons with a late half-life of 9.9 and 17.3 min, respectively. In one baboon at 171 days gestation, the apparent half-life of oxytocin was 9.9 min. The metabolic clearance rates were calculated to be 3.1, 3.2 and 11.7 ml/kg/min, respectively. The production rates were 97, 74, 390 pg/kg/min, respectively. Oxytocin injected into the umbilical vessel near term showed an increase in oxytocin concentration in maternal and uterine vein plasma and amniotic fluid, suggesting that oxytocin can cross the placenta from the foetal to the maternal side. Our findings indicate that in the baboon (1) oxytocin is present throughout pregnancy, (2) uterine activity can be correlated with plasma oxytocin during oxytocin infusion, (3) foetal circulation has higher oxytocin concentration than maternal blood and (4) oxytocin probably can cross the placenta from the foetus to the mother.
LH AND TESTOSTERONE RELEASE IN DEVELOPING BULLS FOLLOWING LH-RH TREATMENT. EFFECT OF GONADECTOMY AND CHRONIC TESTOSTERONE PROPIONATE PRE-TREATMENT.
Authors: Lacroix A. , Pelletier J.
Published: December 2008

LH and testosterone release after LH-RH treatment was studied in male calves from 1 week to 8 months of age. Total LH release, LH peak values and duration of the discharge increased from 1 week to 4 months of age by 406, 453 and 110 %, respectively. Significant decreases of 54, 48 and 24 % were observed at 6 months of age compared to 4 months of age. This was followed by steep increases in those variables of 344, 129 and 69 % at 8 months compared to 4 months. A testosterone response following an LH increase was first seen at 4 months of age when a weak discharge occurred in 2 out of 5 calves. In older calves strong and LH-correlated testosterone responses were always observed.

In a second experiment the LH response to LH-RH was studied in 6 months old calves castrated 2 months previously. The total LH response was 61 % greater than in intact controls. When animals were castrated and pre-treated briefly with testosterone propionate the response was increased by 183 % and the time to reach the LH peak was increased by 360 % From these and other results a synthesis of endocrine events during the first year of life is proposed. In particular it seems that the period between 4 and 8 months of age is crucial since interactions between steroid feedback and pituitary sensitivity to LH-RH change and eventually reach an equilibrium.
INHIBITORY EFFECT OF DIBUTYRYL CYCLIC AMP ON THE RELEASE OF CALCIUM, INORGANIC PHOSPHATE AND LYSOSOMAL ENZYMES FROM CALVARIAL BONES CULTURED FOR 24 HOURS
Authors: Lerner U. , Gustafson G. T.
Published: December 2008

The effect of N6,O2′-dibutyryl adenosine 3′,5′-cyclic-monophosphate (dbcAMP) on the mobilization of calcium (Ca2 +), inorganic phosphate (Pi) and lysosomal enzymes was studied in a bone culture system for 24 h using half calvaria from 6–7 day-old mice. DbcAMP inhibited spontaneous as well as parathyroid hormone-stimulated mineral mobilization. DbcAMP in a concentration of 5 × 10−4m also reduced the activities of β-glucuronidase, β-galactosidase and acid phosphatase found in the media while the activities of lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase were not affected. It is concluded that cAMP is not a stimulator but an inhibitor of bone resorption within the culture period studied (24 h) and that the cyclic nucleotide might interfere with release processes involved in bone resorption.
COMPARISON OF AVIDIN INDUCTION IN THE DIFFERENTIATED AND UNDIFFERENTIATED CHICK OVIDUCT BY PROGESTERONE, ACTINOMYCIN D AND OVIDUCTAL INJURY
Authors: Elo Heikki A.
Published: December 2008

Various oestrogen (diethylstilboestrol, DES) pre-treatments were carried out on chicks and the production of avidin in the oviduct was induced by progesterone, actinomycin D or oviductal injury.

Avidin induction was dose-dependent at doses between 5 mg and 40 mg progesterone/kg or 50 μg and 300 μg actinomycin D/kg respectively. The induction by oviductal injury correlated with the magnitude of tissue injury. First signs of avidin induction were seen at 4 h after oviductal injury, 12 h after progesterone or 12–16 h after actinomycin D administration. Actinomycin D (200 μg/kg), when administered after progesterone injection, did not increase avidin induction by progesterone, this indicating that avidin induction by actinomycin D is not a "superinduction" effect.

Evidence is presented here that the mechanism of avidin induction by oviductal injury and actinomycin D differs from that by progesterone. The differentiation of the oviduct caused by DES treatment was necessary for the induction by progesterone, whereas actinomycin D and oviductal injury also induced avidin in the undifferentiated or poorly differentiated oviduct. Simultaneous DES stimulation potentiated induction by progesterone but not by actinomycin D or oviductal injury. Furthermore, single prior DES stimulation increased avidin induction in the differentiated oviduct of DES-withdrawn chicks caused by progesterone but not that by actinomycin D or oviductal injury.
A POSSIBLE ROLE OF CORPORA LUTEA WITH REGARD TO OESTROGEN-INDUCED CHANGES IN PITUITARY RESPONSIVENESS TO LH-RH
Authors: Schuiling G. A. , Pols-Valkhof N. , Koiter T. R.
Published: December 2008

The effect of oestradiol benzoate (OeB; 3 μg sc) on LH-RH-induced LH-secretory responses was investigated in: (1) long-term ovariectomized (OVX) rats; (2) intact (i.e. sham-OVX) and 24 h-OVX persistent oestrous (PO) rats (intact PO rats do not possess corpora lutea); (3) intact and 24 h-OVX cyclic (dioestrous) rats (intact cyclic rats possess "not-activated" corpora lutea), and (4) intact and 24 h-OVX phase-2-pseudo-pregnant (phase-2-PSP) rats (phase 2 of PSP lasts from day 2 to day 10. Experiments were performed on days 7-8. Intact phase-2-PSP rats possess "activated" corpora lutea).

A "positive" effect of OeB was observed in: (1) long-term OVX rats; (2) intact and 24 h-OVX PO rats; (3) 24 h-OVX cyclic rats and (4) 24 h-OVX phase-2-PSP rats. In intact cyclic and phase-2-PSP rats OeB was completely ineffective.

From these observations it is concluded that only in the absence of corpora lutea OeB can exert a "positive" effect on LH-RH-induced LH-secretory responses. Ovariectomy alone, however, may have a negative impact on LH-RH-induced LH-secretory responses. This holds for PO- and phase-3-PSP rats (phase 3 of PSP begins once the corpora lutea come to lysis, i.e. on or shortly before day 10, and lasts until the end of PSP), but not for phase-2-PSP rats. In cyclic rats, on the other hand, ovariectomy performed on dioestrus-1 "only" interferes with the normal development of pituitary responsiveness to LH-RH and this can be nullified by OeB.

Our observations suggest that (1) relatively long-acting products of corpora lutea "stabilize" (phase-2-PSP rats), c.q. limit the (almost certainly oestrogen-dependent) development of pituitary responsiveness to LH-RH (cyclic and phase-3-PSP rats); (2) in ovariectomized rats the influence of these products vanishes and that (3) this results in a situation in which OeB can become effective. It is also suggested that in the course of the ovulatory cycle and phase 3 of PSP a similar disappearance of corpora luteal products occurs "spontaneously" as a result of the process of luteolysis with as a consequence that the pituitary responsiveness to LH-RH, under the influence of endogenous oestrogens, develops continuously until, on pro-oestrus, an LH-surge occurs.

Evidence is presented that the corpora luteal products, postulated in this paper, are not identical to progesterone.
TWENTY-FOUR HOUR SLEEP-WAKE PATTERN OF PLASMA LH IN PATIENTS WITH ANOREXIA NERVOSA
Authors: Pirke Karl M. , Fichter Manfred M. , Lund Raimar , Doerr Peter
Published: December 2008

The 24-h sleep-wake pattern of plasma LH was studied in 18 patients with severe weight loss. Sixteen patients had anorexia nervosa, one suffered from schizophrenia and one had a gastric ulcer. The age of the patients ranged from 13 to 31 years. Seventeen women and one boy participated in the study. Their weight ranged from 51 to 73 % of the ideal body weight (IBW) at the first 24-h study which was at one week after admission to the hospital. Blood was taken through an indwelling venous catheter every 30 min. The patients' weight increased under behavioural therapy and they were re-studied when they had gained approximately 10 % IBW and again prior to release from the psychiatric ward. The LH patterns were classified as infantile, pubertal or adult. All patients except for two had an iniantile pattern at the first study. Except for the two patients who had no anorexia nervosa, all developed a pubertal and/or an adult pattern. All patients whose weight was below 69 % IBW had an infantile LH pattern. Adult patterns were only seen when the body weight was greater than 80 % IBW. The increase of the average 24-h LH values was slower the older the patients were and the longer they had been anorectic.
TIAPRIDE-INDUCED CHRONIC HYPERPROLACTINAEMIA: INTERFERENCE WITH THE HUMAN MENSTRUAL CYCLE
Authors: L'Hermite M. , Michaux-Duchêne A. , Robyn C.
Published: December 2008

Four regularly menstruating volunteers were submitted to an oral treatment, for 3 consecutive cycles and starting on the first day of a cycle, with tiapride at daily doses ranging from 1 × 100 mg to 2 × 100 mg. The first and the last cycle under treatment, as well as a prior control cycle, were thoroughly studied by means of daily measurements of blood concentrations of LH, FSH, prolactin (PRL), oestradiol and progesterone. Tiapride, a benzamide derivative with dopaminergic blocking activity at the level of the lactotrophes, increased mean PRL secretion in each subject but a permanent hyperprolactinaemia above 700 μU/ml was attained only in one subject.

Despite these widely fluctuating PRL levels in most subjects, the resulting overall hyperprolactinaemia induced in all cases a progressive deterioration of the function of the corpus luteum: 5 cycles showed luteal phases reduced by 2–5 days, one cycle was characterized by some slight luteinisation but questionable ovulation and the 2 remaining cycles were anovulatory. The interruption of drug intake one week after the onset of menses led thereafter to a cycle with a likely inadequate luteal phase but of normal length. It is concluded that even a non-permanent hyperprolactinaemia can impair the normal function of the hypothalamo-pituitaryovarian axis, as well as exhibit some effects in a cycle consecutive to the normalization of PRL.

With the exception of the impaired luteal progesterone secretion, the pooled hormonal data from the short luteal phase cycles under tiaprideinduced hyperprolactinaemia exhibit very little significant differences, as compared to the corresponding values in the control cycles. Some delay in the onset of follicular maturation, however, should be assumed since the follicular phase had been lengthened by 1 to 31 days in 5 of the 6 cycles with luteinisation during treatment.

The present results are compatible with a double impact – both at the ovarian and the hypothalamo-pituitary levels – of hyperprolactinaemia in its mechanisms of impaired function of the hypothalamo-pituitary ovarian axis.
INTERACTION OF [125I]LH-RH AND OTHER OLIGOPEPTIDES WITH PLASMA MEMBRANES OF RAT ANTERIOR PITUITARIES
Authors: Baumann Rudolf , Kuhl Herbert
Published: December 2008

The specific binding of [125I]LH-RH to isolated plasma membranes of rat pituitaries was investigated. The binding process was found to be highly specific, temperature-dependent and saturable. The dissociation constant as calculated by three different methods was approximately 1.3 · 10−8 m, indicating a single type of binding sites. Maximal binding capacity was 1 · 10−12 moles/mg protein (=2 ng LH-RH/pituitary gland), and the number of binding sites was calculated to be 6 · 1011 per mg membrane protein (= 1 · 1010 binding sites/pituitary gland). When diluted with icecold buffer the dissociation of specifically bound LH-RH occurred very rapidly (half-life 3.17 min) with a rate constant of 0.219 min−1. The dissociation process followed first-order kinetics.

Specificity of binding was demonstrated by dose-dependent competition of unlabelled LH-RH, the highly potent analogue D-glutamine-(cyclohexyl)6-LH-RH-nonapeptide-ethylamide and the fragment of an analogue (6-D-Ser(TBu))-LH-RH-(3-9)-heptapeptide-ethylamide with the binding [125I]LH-RH, while angiotensin I, II, oxytocin and bacitracin did not compete. The affinities of LH-RH and the analogue to the binding sites of the pituitary plasma membranes were not consistent with the respective biological activities.