bluuebunny/crossref_metadata_2025_split huggingface dataset:
PITUITARY AND OVARIAN HORMONAL RESPONSE TO 48 h GONADOTROPHIN RELEASING HORRMONE (GnRH) INFUSIONS IN FEMALE RHESUS MONKEYS
Authors: Ferin M. , Bogumil J. , Drewes J. , Dyrenfurth I. , Jewelewicz R. , Wiele R. L. Vande 
Published: December 2008

ABSTRACT
The effects of prolonged gonadotrophin-releasing hormone (GnRH) infusions on LH, FSH, oestrogens and progesterone secretion were studied in female rhesus monkeys at various times of the menstrual cycle and after castration. GnRH was infused at the rate of 15 μg/h for 48 h. This resulted in mean peripheral GnRH levels of 398 ± 31.5 pg/ml (± se) as measured by radioimmunoassay.
As expected the pattern of gonadotrophin responses to GnRH varied considerably with the phase of the menstrual cycle. The largest LH increase was seen during the late follicular phase (6-fold over baseline), with a 3-fold increase during the luteal phase and a 2-fold one during the early follicular phase and in the period following the LH surge. Significant FSH increases (4-fold) were seen only during the follicular phase. Oestrogens increased about 2-fold within 4 h of the start of the infusion during the early follicular phase. In the late follicular phase and during the LH surge, they declined within 24 and 1 h, respectively. Large progesterone increases were seen only during the luteal phase.
Of special interest is the fact that the increase in gonadotrophin secretion could not be maintained for the entire duration of the experiment even though GnRH continued to be infused at rates sufficient to elicit initial increases of several fold over baseline. Gonadotrophin release declined 4–28 h after the initial stimulation. A further decrease below pre-infusion control levels was particularly evident during the midcycle surge and, for FSH, after ovariectomy. These results indicate that a continuous mode of administration may rapidly induce a desensitization phenomenon at the level of the gonadotroph.
A HETEROLOGOUS RADIOIMMUNOASSAY FOR AVIAN PROLACTIN: APPLICATION TO THE MEASUREMENT OF PROLACTIN IN THE TURKEY
Authors: McNeilly A. S. , Etches R. J. , Friesen H. G. 
Published: December 2008

ABSTRACT
A specific heterologous double-antibody radioimmunoassay has been developed to measure turkey prolactin (PRL) using a guinea pig antihPRL antiserum and 125I-labelled ovine PRL [125I]oPRL. Turkey pituitary prolactin and serum give parallel dose-response curves and no cross-reaction is seen with turkey growth hormone, LH or FSH, or mammalian LH, FSH, TSH, GH or placental lactogens. The RIA is accurate and precise and is sufficiently sensitive to measure PRL in all physiological situations investigated in the turkey. The RIA will measure PRL in several avian species including the chicken, duck, goose, pheasant, pheasant × chicken F1 hybrid, pigeon, quail and rook.
Plasma PRL concentrations in laying and broody turkey hens were not significantly different (46.5 ± 2.5 vs. 39.7 ± 3.8 ng/ml) but both were significantly higher (P < 0.001) than in non-laying turkey hens (4.6 ± 0.7 ng/ml).
Oestradiol injection into laying hens did not alter PRL levels while the same injection in non-laying hens caused a significant three-fold increase in plasma PRL levels.
EFFECT OF GLUCOCORTICOIDS ON PLASMA TESTOSTERONE IN MEN
Authors: Schaison G. , Durand F. , Mowszowicz I. 
Published: December 2008

ABSTRACT
ACTH decreases plasma testosterone levels in men. The aim of this study was to assess the part played by the glucocorticoids in this effect, and the mechanism of their action. Plasma androstenedione, testosterone, cortisol and LH were measured in 8 normal men, before and after the following tests: ACTH stimulation (2 mg im), metyrapone administration (500 mg/every 4 h/6 times) and dexamethasone suppression (8 mg/day/3 days). In addition, androstenedione and testosterone were evaluated under human chorionic gonadotrophin (5000 IU HCG/day/3 days) before and after dexamethasone suppression (8 mg/day/6 days).
In all patients, ACTH decreased plasma testosterone from 5.87 ± 1.59 (sd) ng/ml to 3.06 ± 0.8 (sd) ng/ml (P < 0.001). In contrast, after metyrapone, the mean plasma testosterone was increased to 6.98 ± 1.75 (sd) ng/ml. This increase, though not statistically significant, was observed in all patients but one. Both tests resulted in a significant increase of plasma androstenedione (P < 0.01 and P < 0.001, respectively). Dexamethasone suppressed both testosterone and androstenedione levels. None of the three tests had a significant effect on the LH concentration. HCG injection increased the mean plasma testosterone to 11.46 ± 2.80 ng/ml. Dexamethasone significantly depressed (P < 0.01) the testosterone response to HCG.
These data are consistent with the following conclusions: 1) The decrease of plasma testosterone levels, observed in men after ACTH administration, is not observed after metyrapone induced ACTH increase. This confirms that it is related to cortisol levels rather than to ACTH itself. 2) Glucocorticoids act directly on testicular biosynthesis since they do not induce any change in LH secretion and since dexamethasone reduces testosterone response to HCG.
EFFECTS OF HUMAN CHORIONIC GONADOTROPHIN ON THE RELEASE OF CYCLIC AMP AND PROGESTERONE FROM THE SHEEP OVARY AT DIFFERENT STAGES OF THE OESTROUS CYCLE
Authors: Weiss T. J. , Janson P. O. , Porter K. J. , Seamark R. F. 
Published: December 2008

ABSTRACT
The rate of release of cyclic AMP by sheep ovaries containing a corpus luteum was determined at different stages of the cycle before and up to 60 min after an intra-arterial (ia) injection of 500 IU human chorionic gonadotrophin (hCG). The median cyclic AMP concentration in arterial plasma and of ovarian venous plasma following hCG stimulation was 93.2 and 98.0 pmol/ml, respectively. The ovaries of ewes examined at Days 1 and 2 of the cycle showed no response to hCG, whereas in 2 sheep at Day 3, hCG caused a slight response, and in 13 sheep examined between Days 5–18, hCG caused a marked increase in cAMP release. In 5 of the sheep in which both ovarian veins were cannulated, only the ovary with a corpus luteum responded to hCG with an increased secretion rate of cyclic AMP and progesterone. The results indicate a lack of responsiveness in the newly formed corpus luteum to hCG.
CYCLIC AMP AND CYCLIC GMP ACCUMULATION BY ISOLATED HAMSTER GRANULOSA CELLS STIMULATED BY LH AND FSH
Authors: Makris Anastasia , Ryan Kenneth J. 
Published: December 2008

ABSTRACT
Cyclic AMP and cyclic GMP accumulation in hamster granulosa cells as a function of gonadotrophin dose (LH or FSH) and time (0–30 min) was determined. The pattern of acute cyclic AMP accumulation was similar in LH and FSH stimulated granulosa cells, except that the cells were more sensitive to FSH than LH. There was a positive dose response relationship of cyclic AMP accumulation in LH and FSH stimulated cells. LH appeared to partially inhibit FSH stimulated cyclic AMP synthesis. Cyclic GMP accumulation was distinctly different in LH and FSH stimulated cells. An inverse dose response relationship of cyclic GMP to dose LH was observed, with only the lowest dose of LH (0.005 IU/ml) stimulating cyclic GMP synthesis. FSH at 0.005 IU/ml did not stimulate cyclic GMP synthesis, but at higher doses generated cyclic GMP in a positive dose-related manner. The results suggest that specificity of hormone action in granulosa cells may be governed in part by differential on cyclic AMP and cyclic GMP in these cells.
HUMORAL CONTROL OF APPETITE: A URINARY ANOREXIGENIC PEPTIDE. CHROMATOGRAPHIC PATTERNS OF URINARY PEPTIDES IN ANOREXIA NERVOSA
Authors: Trygstad Olav , Foss Irene , Edminson Paul D. , Johansen John H. , Reichelt Karl L. 
Published: December 2008

ABSTRACTS
A "family" of peptides which produced metabolic or behavioural effects following injections into mice or rabbits had been isolated from the urine from patients with the hypothalamic syndrome congenital, generalized lipodystrophy. Anorexia nervosa is associated with hypothalamic disturbances. Precipitates from urine specimens from 25 patients diagnosed as anorexia nervosa were chromatographed on Sephadex G-25 gel columns, and could be divided into 4 different patterns: One was similar to that for normal controls (4), one similar to that observed for patients with schizophrenia (6), 5 patients with a hysteriform type of neurosis had a third form of pattern, and 10 girls considered to have a primary "hypothalamic" type of anorexia nervosa also had typical chromatograms. Fractions influencing appetite in mice were found in the latter group, only. Two peptides influencing appetite were purified through several steps of chromatography. The sequence of the anorexigenic peptide was verified by the synthesis of the tripeptide, pyroGlu-His-GlyOH. A total dose of 12 nmole of this peptide injected daily over 20 days induced food refusal in mice with reduction of food consumption from 5.7 to about 3 g per day, and the mean body weight decreased from 35 to a minimum of 24.1 g. Food consumption did not normalize until 6 months later, at the same time body weights increased to the same level as in the controls. An appetite stimulating peptide increased the daily consumption of food to more than 10 g, and the mean body weight increased to 57.2 g. We provide evidence for the existence of a hypothalamic form of anorexia nervosa, and that the appetite may be regulated by humoral factors. Screening of peptides present in the urine from patients with anorexia nervosa may give diagnostic and therapeutic information.
THE EFFECT OF LH-RH INFUSION ON SERUM LH, FSH AND TESTOSTERONE IN BOYS WITH ADVANCED PUBERTY, DELAYED PUBERTY AND HYPOGONADOTROPHIC HYPOGONADISM
Authors: de Lange W. E. , Snoep M. C. , Doorenbos H. 
Published: December 2008

ABSTRACT
LH-RH injection and infusion studies were performed in advanced puberty, delayed puberty and hypogonadotrophic hypogonadism. No differential diagnosis could be made between delayed puberty and hypogonadotrophic hypogonadism using LH-RH injection. In the LH-RH infusion studies evidence was obtained that stimulation of the pituitary during 4 h results in continuously rising LH levels in advanced puberty and in delayed puberty while in hypogonadotrophic hypogonadism the secretory capacity of the pituitary is gradually exhausted. This phenomenon can be used in the differential diagnosis between delayed puberty and hypogonadotrophic hypogonadism. Though the FSH data point in the same direction they are not useful in this connection as the overlap between the different categories was considerable.
EFFECT OF PYRIDOXINE ON PLASMA LEVELS OF HGH, PRL, AND TSH IN NORMAL WOMEN
Authors: Peters F. , Zimmermann G. , Breckwoldt M. 
Published: December 2008

ABSTRACT
The effect of chronic administration of pyridoxine (vitamin B6) on HGH, basal and TRH stimulated PRL and TSH levels was studied in seven healthy female volunteers. HGH and TSH basal levels remained unaffected. Basal PRL and TRH stimulated PRL and TSH levels were slightly reduced without statistical significance (P > 0.05). The results indicate, that stimulation of the hypothalamic dopaminergic pathway by pyridoxine is highly variable and unpredictable. Therefore it seems meaningless to recommend vitamin B6 for the treatment of hyperprolactinaemia.
THE EFFECT OF A SLIGHTLY ACIDIC SOMATOMEDIN PEPTIDE (ILAs) ON THE SULPHATION OF PROTEOGLYCANS FROM ARTICULAR AND GROWTH PLATE CHONDROCYTES IN CULTURE
Authors: Corvol Marie-Thérèse , Dumontier Marie-France , Rappaport Raphael , Guyda Harvey , Posner Barry I. 
Published: December 2008

ABSTRACT
Chondrocyte cultures were prepared from rabbit growth plate (GPC) and articular (ARC) chondrocytes. These two cell types have distinct morphological characteristics. The cells reached maximum numbers by days 10 and 21 for ARC and GPC, respectively. The proteoglycans (PG) contained in the cellular pool were extracted and purified by DEAE cellulose chromatography. The effect of a partially purified somatomedin peptide with insulin-like activity on [35S] sulphate incorporation into PG was evaluated. In both ARC and GPC a significant stimulation of [35S]sulphate uptake into PG subunits was obtained with 1 ng Eq./ml of somatomedin peptide. In order to obtain the same stimulatory effect with porcine insulin, a 1000-fold greater concentration was required. The electrophoretic patterns of the PG subunits on acrylamide-agarose electrophoresis were identical on control incubations and after stimulation with the somatomedin peptide. These data demonstrate in vitro biological activity of this peptide on well differentiated articular and epiphyseal growth plate chondrocytes in culture. These cultures appear to provide a sensitive biological assay for somatomedin peptides.
ASSESSMENT OF PLACENTAL FUNCTION IN UNCOMPLICATED AND COMPLICATED LATE PREGNANCY BY ESTIMATION OF UNCONJUGATED OESTROGENS IN PLASMA AFTER AN INTRAVENOUS INJECTION OF DEHYDROEPIANDROSTERONE SULPHATE
Authors: Axelsson O. , Nilsson B. A. , Johansson E. D. B. 
Published: December 2008

ABSTRACT
An intravenous injection of 50 mg dehydroepiandrosterone sulphate (DHAS) was given to 60 women in late pregnancy. Following the injection, the plasma concentration of unconjugated oestradiol, oestrone and oestriol was measured at intervals. Radioimmunoassays were used for the estimation of the plasma oestrogens. In women with uncomplicated pregnancies a rapid and pronounced rise was found for plasma oestradiol. No significant changes in the oestradiol response were observed with advancing gestational age from the 32nd to the 40th week of pregnancy. Patients with pre-eclampsia or intrauterine growth retardation (IUGR) showed a lower increase and a later appearance of the peak value. The oestradiol response in diabetic women was similar to that in women with normal pregnancies. The concentration of plasma oestrone rose more slowly and to a minor degree than did oestradiol. No changes were found in the oestrone response with advancing gestational age. In women with preeclampsia and IUGR a lower increase and a later appearance of the maximum level was observed. The oestrone response in diabetic women was indistinguishable from that in women with normal pregnancies. No changes could be detected in the plasma concentration of unconjugated oestriol after the DHAS injection. It is concluded that the great spread in the oestrogenic response limits the clinical usefulness for assessing placental function. However, in women with low basal values of oestriol in urine or plasma the test may be helpful for diagnosing placental insufficiency.
OESTROGEN INDUCED LEYDIG CELL REFRACTORINESS TO GONADOTROPHIN STIMULATION
Authors: Saez J. M. , Haour F. , Loras B. , Sanchez P. , Cathiard A. M. 
Published: December 2008

ABSTRACT
In vivo administration of oestradiol to male rats modifies plasma LH, FSH and testosterone levels, cAMP and testosterone production and DNA synthesis in isolated interstitial cells. Intramuscular injection of oestradiol benzoate (Oe2B) at the dose of 1 or 100 μg/day for 6 days induced a 5- and 10-fold decrease in plasma testosterone, respectively, and a 2-fold decrease in plasma LH and FSH. Plasma testosterone was already significantly decreased 2 h after the Oe2B injection at which point the plasma LH and FSH levels were not yet significantly decreased. In vivo steroidogenic responsiveness to hCG evaluated by plasma and testicular contents was already significantly lower than that of controls 2 h following oestradiol administration. Thereafter response to hCG progressively decreased during the 6 days of 1 or 100 μg oestradiol treatment, reaching 30 and 10 %, respectively, of that of controls on the last day. On the contrary the testicular cAMP content 2 h after hCG injection was significantly higher in oestradiol treated animals than in controls after 24 h. The number of hCG binding sites in isolated Leydig cells decreased to approximately 50 % of that of controls on days 3 to 6 following Oe2B treatment. In vitro testosterone production by isolated interstitial cells, either under basal conditions or under stimulation by hCG or N6O2 dibutyryl adenosine 3′,5′-monophosphate (DbcAMP), was lowered as early as 2 h following the injection of Oe2B to the animals. From 1 to 6 days following Oe2B administration, testosterone secretion, in response to both stimuli, was approximately 4 times lower than that of the control animals. Paradoxically, by the second day of oestrogen treatment, basal and hCG induced in vitro cAMP production by interstitial cells was significantly higher than controls despite a significant decrease in the number of binding sites. The incorporation of thymidine into interstitial cells DNA were decreased following 2 days of oestrogen administration. However, the conversion of pregnenolone to testosterone was unchanged. These inhibitory effects of oestradiol were not overcome by simultaneous administration of hCG.
These results strongly suggest that the rapid inhibitory action of oestradiol on interstitial cell function, steroidogenesis, and DNA synthesis, occurs at the testicular level. Changes observed in gonadotrophin receptor sites or in plasma LH levels may have a long term effect on the steroidogenic refractoriness to hCG. However this refractoriness is primarily related to an abnormality of some step of steroidogenesis beyond cAMP formation.
STUDIES ON A HUMAN CHORIONIC GONADOTROPHIN-LIKE MATERIAL PRESENT IN NON-PREGNANT SUBJECTS
Authors: Robertson D. M. , Suginami H. , Montes H. Hernandez , Puri C. P. , Choi S. K. , Diczfalusy E. 
Published: December 2008

ABSTRACT
The presence of an hCG-like material in urinary and pituitary extracts and plasma obtained from non-pregnant subjects was investigated. Two assay methods were used to detect this material following fractionation of pituitary and urinary extracts by gel filtration (Ultrogel AcA 54) and/or isoelectrofocusing: a) a radioimmunoassay employing an antiserum raised against a specific sequence of the carboxy terminal region (residues 115– 145) of the β-subunit of hCG, and b) an in vitro bioassay method which measures both hLH and hCG activities. The fractionation procedures employed provide a satisfactory separation of highly purified hCG and hLH preparations.
In the pituitary and urinary extracts hCGβ-peptide-like immunoactive (PIA) material was found consistently, which co-eluted with iodinated hCG following gel filtration and possessed pI values similar to those of hCG when subjected to isoelectrofocusing. The PIA material also exhibited in vitro biological activity similar to that shown by hLH and hCG. Detectable levels of immunoactive material were also found in plasma; however, the plasma levels of this PIA material were not influenced by classical endocrine measures such as the stimulation or inhibition of gonadotrophin secretion. The low levels of this material in plasma precluded its further characterization by gel filtration or electrofocusing.
Whereas the present data and those reported by other investigators seem to suggest the presence of some hCG-like material in urinary and pituitary extracts and possibly in plasma of non-pregnant subjects, it is emphasized that the available evidence is not sufficiently conclusive to exclude other interpretations as to the nature of this material.
ULTRASTRUCTURAL MORPHOMETRY OF SPARSELY GRANULATED PROLACTIN CELL ADENOMAS OF THE HUMAN PITUITARY
Authors: McComb D. J. , Kovacs K. 
Published: December 2008

ABSTRACT
Fifteen sparsely granulated prolactin-producing adenomas and 10 non-tumourous adenohypophyses, removed by surgical hypophysectomy, have been studied using morphometry at the electron microscopic level. Compared to non-tumourous prolactin cells, sparsely granulated adenomatous prolactin cells showed a significant decrease in diameter and volume density of secretory granules and an increased volume density of rough-surfaced endoplasmic reticulum and Golgi apparatus. The volume density of mitochondria remained unchanged. These results indicate that the cells of the adenoma are in a highly active functional state. It appears that the equilibrium between hormone synthesis, storage and release is altered in adenomatous prolactin cells.
PRIMARY ALDOSTERONISM: INABILITY TO DIFFERENTIATE UNILATERAL FROM BILATERAL ADRENAL LESIONS BY VARIOUS ROUTINE CLINICAL AND LABORATORY DATA AND BY PERIPHERAL PLASMA ALDOSTERONE
Authors: Vetter H. , Siebenschein R. , Studer A. , Witassek F. , Furrer J. , Glänzer K. , Siegenthaler W. , Vetter W. 
Published: December 2008

ABSTRACT
In 31 patients with primary aldosteronism routine clinical and laboratory data, the effect of orthostasis on plasma aldosterone (PA), plasma renin activity (PRA) and cortisol (PC), effect of fludrocortisone or high sodium intake on basal PA and night-day fluctuations of basal PA and PC with and without suppression of pituitary ACTH by dexamethasone were determined to differentiate patients with a unilateral aldosterone producing tumour (adenoma, APA, n = 20; carcinoma, CA, n = 1) from those with idiopathic bilateral adrenal hyperplasia (IAH, n = 10).
Mean systolic and diastolic blood pressure, age, serum sodium, serum potassium and urinary excretion of sodium and potassium were not significantly different in both groups of patients. Normokalaemic primary aldosteronism occurred both in patients with APA (n = 2) and in patients with IAH (n = 1). Mean basal PA and mean urinary excretion rate of aldosterone-18-glucuronide were higher though not significantly different in patients with APA or CA than in those with IAH. A substantial number of the patients with APA (n = 5) and with IAH (n = 3) showed urinary excretion rates of aldosterone-18-glucuronide ≦ 13 μg/24 h.
Mean PA and PRA significantly increased (P < 0.025) in patients with IAH in response to posture. However, these changes also occurred at times in some patients with APA.
Both fludrocortisone and high sodium intake produced a variable and no group-specific effect on basal PA.
Night-day variations in PA were positively correlated with those in PC in all patients with APA (n= 12) and in 5 of 8 patients with IAH. A dissociation of PA and PC, however, was only observed in patients with IAH. Finally, the effect of dexamethasone on plasma aldosterone curves was variable in both groups of patients.
Our results indicate that under the described conditions analysis of routine clinical and laboratory data and of peripheral PA, PRA and PC are of limited value in differentiating patients with APA or CA from those with IAH.
CHOLINERGIC INFLUENCES ON HYPOTHALAMIC-PITUITARY-ADRENOCORTICAL ACTIVITY OF STRESSED RATS: AN APPROACH UTILIZING CHOLINE DEFICIENT DIETS
Authors: Sithichoke N. , Malasanos L. J. , Marotta S. F. 
Published: December 2008

ABSTRACT
Male rats were placed on choline (Ch) deficient diets for 3 to 14 days, without and with Ch (normal and large doses) supplemented in the drinking water, to determine whether altering the availability of Ch would affect the cholinergic system in relation to the latter's role in modulating the hypothalamic-pituitary-adrenocortical (HPA) system of non-stressed and stressed animals. The results indicate that the basal nonstressed activity of the HPA system, as assessed by adrenal and plasma corticosterone concentrations, was not affected by placing the animals on these diets for as long as 14 days. Furthermore, the in vitro production of corticosterone by these adrenal glands, in the presence or absence of adrenocorticotrophin, was similar to those observed in animals on a regular rat diet; however, the HPA responses to auditory (100 db) stress, and to a lesser extent hypercapnic (9 % CO2) stress, were impaired on the Ch deficient diet (14 days), and these responses were partially corrected by supplementing the diet with Ch in the drinking water. Thus, the data suggest that altering the dietary intake of Ch may affect cholinergic activity, which in turn affects the HPA response to stressors.