bluuebunny/crossref_metadata_2025_split huggingface dataset:
INFLUENCE OF PSORALEN ON MELATONIN FORMATION IN RAT PINEAL GLAND IN ORGAN CULTURE
Authors: Bäckström Maria , Wetterberg Lennart 
Published: December 2008

ABSTRACT
8-Methoxypsoralen (10−4 m) added to the medium of rat pineal glands in organ culture induces a five-fold increase of 14C-labelled N-acetylserotonin and melatonin formation when serotonin is used as 14C-labelled precursor. Addition of d-amphetamine (10−5 m) to pineal glands also results in an increase of N-acetylserotonin and melatonin formation. This increase is enhanced by the addition of 8-methoxypsoralen (10−5 m). In pineal glands pre-incubated for 24 h 8-methoxypsoralen (10−4 m) caused an increased production of N-acetylserotonin and melatonin. This indicates that the effect of 8-methoxypsoralen is mediated through a post-synaptic event and not by release of noradrenaline or blocked re-uptake of amines to nerve terminals in the pineal gland. Further studies of the clinical significance of the effect of psoralen on pineal gland metabolism seems warranted.
THE EFFECT OF 2-BROMO-α-ERGOCRYPTINE AND 2-CHLORO-α-METHYLERGOLINE-8β-ACETONITRILE (LERGOTRILE MESYLATE) ON THE PROLACTIN SECRETION OF THE EWE
Authors: Hooley R. D. , Fell L. R. , Findlay J. K. 
Published: December 2008

ABSTRACT
The effects of two ergot alkaloids, 2-bromo-α-ergocryptine methane-sulphonate (CB154, Sandoz) and lergotrile mesylate (LM, E. Lilly & Co.), on the basal secretion of prolactin and on the prolactin response to TRH or the milking stimulus was investigated in the sheep. Both CB154 (c. 0.5 mg/kg) and LM (c. 0.75 mg/kg) markedly reduced basal levels of prolactin and inhibited the TRH-induced prolactin release in ewes in the mid-luteal phase of the oestrous cycle. Both compounds also suppressed basal levels of prolactin in lactating ewes and inhibited the prolactin response to the milking stimulus in lactating ewes.
VASOPRESSIN TEST: DIAGNOSTIC INACCURACY IN EVALUATION OF HYPOTHALAMIC-PITUITARY-ADRENOCORTICAL AXIS
Authors: Leisti Seppo , Perheentupa Jaakko 
Published: December 2008

ABSTRACT
An im vasopressin test was given to 141 children and adolescents, 52 with normal HPA axis and 89 with evident or suspected defect of the axis, and repeated in 36 cases, to establish criteria of a normal response, and to examine the accuracy and precision of the responses. Comparisons were made with the responses to the 2-h ACTH, insulin and 3-h metyrapone test.
The distributions of plasma cortisol levels and increments were positively skew, and a log transformation was made for appropriate statistical analysis. Maximal plasma cortisol level was positively and maximal increment negatively correlated with the basal level. In precision, the maximal level was superior to the maximal increment. Hence, a normal result was best defined by an area around the regression of maximal level on basal level in the normal series. The best single index of the response was the maximal level. A useful new method was introduced for quantitative comparison of plasma cortisol responses to different tests.
The vasopressin test result was frequently normal in patients who, according to repeated insulin tests were ACTH-deficient. Furthermore, the 10 patients with organic expansive hypothalamic lesions had a mean vasopressin response, that was greater relative to the insulin response than that of the reference series. However, 3 of 21 patients with organic non-expansive hypothalamic disease gave a subnormal vasopressin response but a normal insulin response. Moreover, in isolated GH deficiency and after prednisone medication the mean vasopressin response was lower relative to the insulin response than in the reference series. Thus, this test is not reliable in screening for, or in anatomical diagnoses of ACTH deficiency.
EFFECTS OF SEX STEROIDS ON GROWTH HORMONE PRODUCTION IN CULTURED RAT PITUITARY CELLS
Authors: Haug E. , Gautvik K. M. 
Published: December 2008

ABSTRACT
Monolayer cultures of rat pituitary tumour cells (GH3) were used to study the effects of different sex steroids on growth hormone (GH) production expressed as the amount of extracellular hormone which accumulated during 24 h. The hormone was measured with a sensitive and specific radioimmunoassay.
Oestradiol-17β (10−12 mol/l—10−6 mol/l) caused a dose-dependent decrease in GH production with the maximum effect (30 % of controls) at 10−10 mol/l. After the cessation of treatment with oestradiol-17β (10−8 mol/l for 7 days), control levels of GH were obtained within 11 days, after a transient augmentation of production. Progesterone (10−11–10−6 mol/l) caused a dose-dependent stimulation of GH production, and the maximum effect (160 % of controls) was observed at 10−6 mol/l. Testosterone (10−6 mol/l) decreased the production of GH to 70 % of control values, whereas 5α-dihydrotestosterone (DHT) had no effect. Cell growth was not affected by any of the sex steroids. Corticosterone (10−6 mol/l) increased GH production to about 400 % of control values, and this effect was inhibited by oestradiol-17β (10−6 mol/l). The hypothalamic peptides, thyrotrophin releasing hormone (TRH) and somatostatin, that both depressed GH production did not significantly inhibit the stimulatory effect of corticosterone. When used in combination, the effects of oestradiol-17β (10−6 mol/l) and TRH (3 × 10−7 mol/l) were additive which was not the case for the combination oestradiol-17β (10−6 mol/l) and testosterone (10−6 mol/l).
These results suggest different mechanisms of action of peptide and steroid hormones on GH production in the GH3 cells. If the properties of the GH3 cells reflect those of normal somatotrophs the sex steroids may alter GH production at the pituitary level, an influence that may be further modulated by corticoids, TRH and somatostatin.
RADIOIMMUNOASSAY OF THYROTROPHIN-RELEASING HORMONE (TRH) IN NORMAL SUBJECTS, IN ABNORMAL THYROID STATES AND UNDER CATECHOLAMINERGIC INFLUENCES
Authors: Lombardi G. , Panza N. , Cei S. , Cosimato F. , Minozzi M. 
Published: December 2008

ABSTRACT
Plasma TRH was determined by radioimmunoassay in normal and abnormal thyroid state. In euthyroid adult subjects, the plasma TRH level were 31.9 ± 11 pg/ml (mean ± sd). No significant differences were observed with regard to sex, pregnancy or age, except for the acute increase in newborn infants. The plasma TRH levels evaluated in abnormal thyroid states were found significantly (P < 0.001) increased in hyperthyroidism (49.1 ± 14 pg/ml) and decreased in hypothyroidism (22.1 ± 6 pg/ml). Nor were any significant differences observed in simple goitre, pituitary adenoma and empty sella. Lastly, plasma TRH and TSH levels were also evaluated after acute administration of L-dopa, 2-Br-α-ergocriptine and chlorpromazine in normal and hypothyroid subjects. Contemporaneous modifications of plasma TRH and TSH levels (decreased after L-dopa and 2-Br-α-ergocriptine, increased after chlorpromazine) were observed in hypothyroidism.
The results indicate that plasma TSH modifications at birth as well as under catecholaminergic influences are at least partially mediated by variations of TRH secretion. Moreover, the inverse plasma TRH and TSH modifications in abnormal thyroid states agree with different feedback effects at the hypothalamic (positive) and pituitary (negative) level. It is possible that the significance of the positive feedback at the hypothalamic levels can be interpreted when taking into account the extra-pituitary effects of TRH.
OPPOSITE VARIATIONS IN SERUM T3 AND REVERSE T3 DURING PROPYLTHIOURACIL TREATMENT OF THYROTOXICOSIS
Authors: Laurberg Peter , Weeke Jørgen 
Published: December 2008

ABSTRACT
Blood samples for determination of serum total and free reverse triiodothyronine (rT3), triiodothyronine (T3) and thyroxine (T4) were obtained daily in 6 previously untreated thyrotoxic patients during periods of propylthiourazil (PTU) (600 mg per day) or methimazol (MMI) (45 mg per day) administration.
PTU induced about 60 per cent increase in both total and free serum rT3. This was accompanied by a rapid decrease in serum T3 and a more gradual decline in serum T4. MMI administration to untreated patients was followed by a gradual parallel decrease in rT3, T3 and T4. Turn from PTU to MMI produced a rapid decrease in serum rT3 and increase in serum T3 in all 6 patients. The relative variations in the free and total concentrations of iodothyronines were practically identical.
The increase in serum rT3 after PTU is most likely explained either by enhanced deiodination of T4 to rT3 or by an inhibitory effect of PTU on rT3 degradation.
THE TEST OF OVERLOADING OF L-DIIODOTYROSINE (DIT) IN THE SCREENING OF IODOTYROSINE DEHALOGENASE DEFICIENCY
Authors: Codaccioni J. L. , Rinaldi J. P. , Bismuth J. 
Published: December 2008

ABSTRACT
The hereditary nature of goitrous hypothyroidism due to the iodotyrosine dehalogenase deficiency (IDD) has been suspected. In order to demonstrate a partial deficiency in the relatives and parents of the patients we studied, using urinary elimination, the peripheral deiodination of labelled L-diiodotyrosine (DIT). The usual procedure consists of a standard test which was performed by iv injection of a tracer dose of radioactive DIT. In order to increase the sensitivity of the method we used a test of overloading, carried out by iv administration of 20 to 25 mg of highly purified [127I]L-DIT labelled with 50 μCi of 125I in adults and a lower dose in children. After injection the quantity of non-deiodinated DIT was measured in urinary samples at intervals of 0 to 2, 2 to 6 and 6 to 24 h. In 15 normal subjects the urinary elimination of DIT in 6 h varied from 1.9 to 23.9% of the injected dose. In 8 goitrous hypothyroid patients, 52 to 79.9 % was eliminated, most of the excretion occurring during the first 2 h. In 22 relatives of the patients it was 6.9 to 43 % of the dose, and in one of the patient's relatives who was clinically normal it was 70.9 %.
A statistically study showed that the most significant characteristic was the percentage of DIT excreted during the first 2 h. Elimination in the normal group was 11.4% (sd 5.8) while that of the parents and relatives of goitrous hypothyroid patients was 20.4 % (sd 12.5). Thus the 2 groups are statistically different but with a poor P-value (P < 0.05). Discriminant analysis permitted classification of each relative with respect to the control group: among 23 parents and relatives, 15 differed from the controls and were suspected of representing a partial IDD. The latter can be considered as heterozygotes, and according to the results of the proposed DIT overloading test the transmission of congenital IDD is determined as an autosomal recessive trait. However, in one family, the hypothesis of the variable expressivity of a genetic dominant trait must be considered.
STEROID METABOLISM IN THE PERFUSED HUMAN PLACENTA
Authors: Wolf Alfred S. , Musch Klaus A. , Speidel Werner , Strecker Jürgen R. , Lauritzen Christian 
Published: December 2008

ABSTRACT
A new model for the perfusion of human term-placentas has been developed for studies on the placental biogenesis of C-18 and C-19 steroids. For viability criteria, the glucose- and oxygen-consumption, regional perfusion control by dye-infusions or scanning after injection of 99Tc-labelled macroparticles, and the histological qualification were chosen. The recycled perfusate was investigated for the steroids oestrone (Oe1), oestradiol-17β (Oe2), oestriol (Oe3), 4-androstene-3,17-dione (A), testosterone (T), and human placental lactogen (HPL) by radioimmunoassay in controls and perfusions with the foetal steroid precursor dehydroepiandrosterone sulphate (DHA-S). In control perfusions, steroid hormones were found in constant ratios (Oe1:Oe2:Oe3:T:A = 30:1.5:100:0.35:1). Following the administration of 10 mg DHA-S for testing the metabolic capacity of the organ, high concentrations of Oe1 (90–720 ng/ml = 250–3970 % as compared to 100% pre-injection values) were found, shortly preceded by a rapid increase of A (66–1000 ng/ml = 100–16 000 %). A typical surge of T (5.3–147 ng/ml = 265–4640 %) preceded the normally slower increment of Oe2 (22–220 ng/ml = 1570–4330 %). The concentrations of Oe3 and HPL remained nearly unchanged. From different steroid patterns after DHA-S-load, two distinct responses of term-placentas could be differentiated: Group I (n=12) showed high concentrations of Oe1 (3200 ± 940 %), a small increase of T (1020 ± 500%), as well as low and delayed values of Oe2 (1660 ± 450%). In Group II (n = 5), values were high for T (3160 ± 1020%) and Oe2 (3300 ± 1110%), whereas Oe1 was found in a lower range (508 ± 302%).
In contrast to in vivo findings in maternal venous blood after DHS-S injection to the mother, oestrone was found in perfusions as the main oestrogen fraction from DHA-S. Thus, the analysis of such metabolic differences might be of help in the interpretation of complex results from the DHA-S-loading test.
INDUCTION OF PREMATURE PARTURITION IN SHEEP: ADRENOCORTICOTROPHIN AND CORTICOSTEROID CHANGES DURING INFUSION OF SYNACTHEN INTO THE FOETUS
Authors: Jones C. T. , Johnson P. , Kendall J. Z. , Ritchie J. W. K. , Thorburn G. D. 
Published: December 2008

ABSTRACT
Synacthen (10 μg/h) infused into foetal sheep at about day 125 of gestation caused premature delivery within 4 days. During the first 24 h of the infusion the secretion of adrenocorticotrophin was depressed and the assayable hormone concentration was within 500–1000 pg/ml. Subsequently, large fluctuations occurred in the adrenocorticotrophin concentration in the pasma of foetal sheep which were consistent with the stimulation of adrenocorticotrophin secretion. No transfer of Synacthen to non-infused twin foetuses was observed. The plasma corticosteroid concentration in the infused foetus also showed a small rise during the first 24 h of the infusion followed by large fluctuations in concentrations that coincided with the changes in adrenocorticotrophin. No consistent changes in the plasma corticosteroid concentration in the non-infused twin foetus were observed. These results are discussed in relation to the hormone changes occurring during normal delivery.
PROLACTIN-LOWERING EFFECT OF LOW DOSES OF LISURIDE IN MAN
Authors: Horowski R. , Wendt H. , Gräf K.-J. 
Published: December 2008

ABSTRACT
Lisuride, a new semisynthetic ergot derivative, effectively decreased the TRH-induced hyperprolactinaemia in healthy female volunteers at a dose of 300 μg given orally. Basal prolactin levels were suppressed after a single dose of 100 and 200 μg lisuride. This effect was still present 6 h after administration. Two hundred μg lisuride also decreased the high serum prolactin levels produced by im injection of 50 mg sulpiride, and conversely, sulpiride injection abolished the prolactin lowering effect of lisuride. These results demonstrate that in man too lisuride is a very potent prolactin-lowering agent. In addition, the data support the hypothesis of a predominant role of dopaminergic mechanisms in the regulation of prolactin secretion.
SHORT-TERM REGULATION OF LH AND FSH SECRETION IN CYCLIC WOMEN
Authors: Römmler A. 
Published: December 2008

ABSTRACT
The effects of two iv 25 μg LH-RH injections (180 tests) at different intervals (30 min to 24 h) on radioimmunoassayable serum LH and FSH levels were investigated in 30 women in the midfollicular or midluteal phase of the menstrual cycle.
The pituitary LH and FSH response to the second LH-RH injection at time-intervals of 30 and 360 min was significantly lower than the response elicited after the first injection. The second response was significantly higher at 60 to 180 min intervals. The maximum increment occurred at 120 min. No significant differences between the two pituitary responses to LH-RH were found at intervals of 240 min and 24 h.
A theory with regard to intracellular processes of hormone synthesis and degradation is proposed to explain these time-dependent differences in the pituitary LH and FSH response.
IMPORTANCE OF INSULIN SECRETION BASED ON THE RATE OF CHANGE IN BLOOD GLUCOSE CONCENTRATION IN GLUCOSE TOLERANCE, ASSESSED BY THE ARTIFICIAL BETA CELL
Authors: Kawamori Ryuzo , Shichiri Motoaki , Goriya Yoshikazu , Yamasaki Yoshimitsu , Shigeta Yukio , Abe Hiroshi 
Published: December 2008

ABSTRACT
The dynamic property of glucose-induced insulin secretion was simulated with the aid of a control theory, and the relationship between the stepwise input of glucose concentration and the biphasic response of insulin as an output was expressed in the transfer function of proportional plus derivative action to glucose concentration. By utilizing this model, the following computer algorithm for the artificial beta cell was made; rate of insulin infusion = Kp BG + Kd ΔBG+ Kc, where BG was the abbreviation for glucose concentration, ΔBG was the rate of change in BG, Kp and Kd were the coefficient for the proportional and derivative action, respectively, and Kc the constant for basal insulin secretion.
Microcomputer, insulin pump and digital printer were packed in small case, which was connected with glucose analyzer.
Experiments were carried out in the depancreatized dogs to validate the importance of infused insulin based on derivative action to glucose concentration in glucose regulation. Kd/Kp ratio was changed when insulin was infused following iv glucose bolus injection. The results revealed that when the derivative action was added to the proportional action properly in insulin infusion regulatory system, insulin requirement was the smallest and glucose regulation was the best.
The characteristics of the system recognized in clinical application were 1) rate of insulin infusion was small enough to keep the plasma concentration of insulin at a physiological level, then insulin requirements were reduced to around a half of those given subcutaneously, 2) glucose or glucagon to restore hypoglycaemia was not essential.
ROLE OF CYCLIC AMP IN OOCYTE MATURATION AND GLYCOLYSIS IN THE PRE-OVULATORY RAT FOLLICLE
Authors: Hillensjö Torbjörn , Ekholm Carl , Ahrén Kurt 
Published: December 2008

ABSTRACT
This study was undertaken in order to analyse the role of cyclic AMP (cAMP) in the stimulatory action of LH on the resumption of oocyte meiosis (oocyte maturation) and follicular glycolysis. Follicular development was induced in immature rats by a single injection of pregnant mares' serum gonadotrophin. Pr-ovulatry follices were extirpated on the day before ovulation and incubated in a chemically defined medium for 4–10 h. The follicle-enclosed oocytes remained in the dictyate stage when incubated in hormone-free medium but in the presence of LH oocyte maturation was induced. When cAMP or butyryl derivatives of cAMP were added to the incubation medium no effect on the oocyte was seen. However, these nucleotides prevented the stimulatory action of LH on the oocytes. The phosphodiesterase inhibitors theophylline and IBMX had similar effects as cAMP on oocyte maturation, causing a reversible blockage of the LH effect. When 8-Br-cAMP and the phosphodiesterase inhibitor ICI 63.197 were tested it was found that both had inherent stimulatory effects on oocyte maturation at certain concentrations. Pre-incubation of the follicles in a high concentration of dibutyryl cAMP followed by transfer to plain medium resulted in oocyte maturation.
Follicular lactate production was stimulated by all cyclic nucleotide derivatives tested, except cAMP, and by IBMX and ICI 63.197. There was no reduction by these agents of the stimulatory effect of LH on lactate production.
A model to explain the role of cAMP in oocyte maturation is presented.
FERTILE EUNUCH SYNDROME VERSUS CLASSIC HYPOGONADOTROPHIC HYPOGONADISM
Authors: Smals A. G. H. , Kloppenborg P. W. C. , van Haelst U. J. G. , Lequin R. , Benraad T. J. 
Published: December 2008

ABSTRACT
The functioning of the hypothalamo-pituitary-target organs axis was assessed in 3 patients with 'fertile eunuch' syndrome (FE) and 6 patients with 'classic' hypogonadotrophic hypogonadism (HH) with or without hyposmia. Both groups of patients did not differ from each other with regard to basal serum prolactin levels, pituitary growth hormone and thyrotrophin reserve and the thyroid or adrenal gland function. Both groups differed, however, with respect to the hypothalamo-pituitary-gonadal function: 1. the pituitary LH response to exogenous LH-RH was (low)-normal in FE and blunted in HH; 2. the basal FSH levels were normal in FE and undetectable in HH; 3. the basal LH levels were normal in FE and 3/6 patients with HH and low in the remaining three; 4. the basal and HCG stimulated plasma testosterone concentrations were significantly higher in FE than HH. The data suggest that FE represents a less severe form of LH-RH deficiency, rather than a distinct disorder.
SUPRAHYPOPHYSEAL DYSFUNCTION IN A PATIENT WITH ASEXUAL ATELEIOSIS
Authors: Medina Martha , Parra Adalberto , Scaglia Hugo E. , Nieto Laura , Pérez-Palacios Gregorio 
Published: December 2008

ABSTRACT
The neuroendocrine function of a 19 years old female dwarf with primary amenorrhoea and lack of sexual development (asexual ateleiosis) was studied. Undetectable fasting plasma levels of growth hormone (GH) and a lack of response to three different provocative stimuli was observed. Oestrogen administratin did not modify the GH response. Thyroid and adrenal function were within normal limits. Undetectable plasma levels of immunoreactive oestradiol and lack of oestrogenic activity in vaginal smears indicated absence of ovarian function. Low levels of circulating gonadotrophins with a significant rise after synthetic LH-RH administration was demonstrated, while clomiphene citrate failed to induce ovulation. Following 6 months of continuous GH administration a significant increase in the growth rate was evident, whereas no pubertal development was observed. These data are interpreted as demonstrating the suprahypophyseal origin of the sexual infantilism in a patient with inappropriate GH secretion. It is suggested that a combined deficiency of LH-RH and GH-RH may account for the aetiology of this disorder.
PITUITARY STIMULATION TEST IN AMENORRHOEIC PATIENTS WITH NORMAL OR LOW SERUM OESTRADIOL
Authors: Kletzky Oscar A. , Mishell Daniel R. , Davajan Val , Nicoloff John , Mims Robert , Nakamura Robert M. 
Published: December 2008

ABSTRACT
A group of 15 patients with secondary amenorrhoea were studied. In 8 of these patients (hypothalamic-pituitary dysfunction, HPD) the baseline plasma Oe2 concentration (47.7 ± 6.0 pg ml) was similar to the early follicular phase levels of the 9 control subjects (48.8 ± 3.3 pg/ml). The remaining 7 patients (hypothalamic-pituitary failure, HPF) had significantly lower plasma Oe2 values (19.8 ± 2.6 pg/ml). Plasma LH and FSH levels were similar in the two groups of patients as well as the controls. All patients and control subjects were sequentially stimulated with insulin induced hypoglycaemia, GnRH-TRH and then GnRH alone. Although abnormal GH and PRL responses to hypoglycaemia and blunted PRL responses to TRH were obtained in the two groups of patients the results could not be correlated with plasma Oe2 baseline values. In both groups of patients, cortisol and TSH responses were comparable to the control subjects. Following the administration of GnRH the maximum LH response in patients of the HPF group was significantly lower (P < 0.025) than the LH response in patients of the HPD group. No statistically significant difference was found in the FSH response between the two groups.
In conclusion, most of the patients with secondary amenorrhoea due to HPD have been shown to have most probably a hypothalamic derangement. Patients with HPF may have either a more profound hypothalamic involvement or an intrinsic pituitary alteration.