bluuebunny/crossref_metadata_2025_split huggingface dataset:
MECHANISM OF ANTIPROGESTATIONAL ACTION OF SYNTHETIC STEROIDS
Authors: Tamaya Teruhiko , Furuta Norio , Motoyama Toshihiko , Boku Sinko , Ohono Yousuke , Okada Hiroji 
Published: December 2008

ABSTRACT
This study was designed to investigate the mechanism of antiprogestational action of synthetic steroids, danazol (17α-hydroxy-pregn-4-en-20-yno [2,3-d] isoxazol-17-ol) and R2323 (13β-ethyl-17α-hydroxy-18,19-dinor-17α-pregna-4,9,11-trien-20-yn-3-one). Oestrogen primed rabbit uteri were used for this study. The sucrose gradient analysis in the supernatant of 248 000 x g (max.) of the uterine homogenate showed that progesterone8S binding was inhibited by each of the synthetic steroid, and the kinetic study revealed that each steroid was a competitive inhibitor, where Kd of progesterone-protein binding was 8.1 × 10−10 m, Ki of danazol-protein binding was 2.7 × 10−8 m and Ki of R2323-protein binding was 6.6 × 10−9m. These results indicate that these synthetic steroids bind to progesterone receptor with moderate binding affinities. The modified Anderson's exchange assay of nuclear receptor demontrated that danazol- or R2323-receptor complex can enter into the uterine nuclei in a lesser degree than does progesterone-receptor complex. RNA synthesis by the uterine chromatin was stimulated if the progesterone-receptor complex was added, but this stimulation was inhibited by addition of danazol or R2323. The chromatin RNA transcription was not induced by danazol- or R2323-receptor complex.
These results suggest that such a synthetic steroid binds to a progesterone receptor, and the steroid-receptor complex enters into the nucleus but does not activate the chromatin template, thus resulting in the antiprogesational effect.
EFFECT OF ENDOCRINE MANIPULATIONS ON GLUCOCORTICOID BINDING CAPACITY IN RAT SKELETAL MUSCLE
Authors: Mayer Michael , Rosen Fred 
Published: December 2008

ABSTRACT
[3H]Dexamethasone binding capacity in rat muscle cytosol was determined after various endocrine manipulations in an attempt to identify factors which might regulate the level of the cytoplasmic hormone receptor protein. Hypophysectomy and adrenalectomy markedly increased the specific binding of [3H]dexamethasone in skeletal muscle cytosol, while implantation of the MtT tumour which secretes ACTH and growth hormone, as well as treatment with glucocorticoids reduced the glucocorticoid specific binding. Since the effects of hypophysectomy and the MtT tumour depend on the presence of the adrenals, they appear to be mediated via changes in circulating glucocorticoid level. Alloxan- or streptozotocin-induced diabetes caused only a slight reduction in the binding of [3H]dexamethasone in muscle, suggesting that the enhanced responsiveness to glucocorticoids in diabetes is not due to increased glucocorticoid receptor activity. There is a sex-dependent effect on binding, female rats having a higher concentration of binding sites. Furthermore, treatment with the synthetic androgen fluoxymesterone or with glucocorticoids reduces binding, while oestradiol-17β enhances it.
The changes in glucocorticoid binding capacity induced by the various endocrine manipulations appear to reflect mainly changes in receptor concentration rather than occupancy, since the binding assays were preformed after a suitable time allowance for removal of the administered hormones by metabolism.
IN VITRO EFFECTS OF THEOPHYLLINE AND AMINOGLUTHETIMIDE UPON BASAL AND ACTH INDUCED cAMP LEVELS AND STEROID OUTPUT BY THE NORMAL HUMAN ADRENAL GLAND
Authors: Honn Kenneth V. , Chavin Walter 
Published: December 2008

ABSTRACT
The in vitro effects of theophylline and aminogluthetimide upon basal and ACTH stimulated cAMP, cortisol and aldosterone responses of normal human adrenocortical tissue were evaluated. Theophylline increased basal cAMP levels and cortisol output, however, basal aldosterone output was depressed. Theophylline in concert with ACTH depressed cortisol and aldosterone output. Aminogluthetimide alone did not affect basal cAMP levels, however, the normal cAMP response to ACTH was delayed in aminogluthetimide pre-treated adrenals. Aminogluthetimide also depressed basal and ACTH stimulated cortisol and aldosterone output with the latter being more sensitive. The findings indicate that both theophylline and aminogluthetimide produce effects upon the adrenal in addition to inhibition of phosphodiesterase and cholesterol side-chain cleavage, respectively. Further, theophylline depression of ACTH stimulated steroid output may be helpful in understanding the interplay between a number of factors in the control of adrenal steroid biosynthesis and release.
CIRCADIAN AND CIRCANNUAL RHYTHMS IN PLASMA HORMONES AND OTHER VARIABLES OF FIVE HEALTHY YOUNG HUMAN MALES
Authors: Reinberg Alain , Lagoguey Michel , Cesselin François , Touitou Yvan , Legrand Jean-Claude , Delassalle Annick , Antreassian Joséphine , Lagoguey Alenka 
Published: December 2008

ABSTRACT
Every other month (plasma) and every month (urine) circadian rhythms were documented during the course of 14 months. Annual changes were validated in the 24 h mean of: plasma FSH (annual crest time: February), LH (March), thyroxine (September), cortisol (February), renin activity (April), testosterone (October), urinary 17-hydroxycorticosteroids (March), aldosterone (March), potassium (May) as well as sexual activity (September) [self-recorded daily]. Plasma prolactin did not show an annual variation. In addition, annual changes in the circadian acrophase (crest time location in the 24 h scale) occurred for some of the documented variables: plasma thyroxine, cortisol, renin activity, testosterone, urinary aldosterone and potassium.
EFFECTS OF CIMETIDINE ON PROLACTIN, LH, AND SEX STEROID SECRETION IN MALE AND FEMALE VOLUNTEERS
Authors: Bohnet H. G. , Greiwe M. , Hanker J. P. , Aragona C. , Schneider H. P. G. 
Published: December 2008

ABSTRACT
The histamine H2-receptor antagonist cimetidine, which has recently been introduced for the treatment of gastric and duodenal ulcers and haemorrhage, respectively, stimulates prolactin (PRL) secretion. The release of PRL after a bolus injection of the compound is significantly higher in female than in male volunteers, and is more pronounced during the luteal than during the follicular phase of the menstrual cycle. Oral administration of the drug stimulates PRL to a similar extent as parenteral administration. Treatment of male and female volunteers with cimetidine for 20 days (1 g/day orally) resulted in elevated serum PRL concentrations in both sexes. Basal LH levels as well as the response to 25 μg LH-RH were not significantly changed after treatment. Testosterone levels in males and oestradiol levels in females were not altered. Luteal progesterone, however, was significantly diminished in the menstrual cycles when cimetidine was given. The mechanism underlying the stimulatory effect of cimetidine on PRL secretion is not clear, but it does not seem that this ability is exerted via an inhibition of pituitary dopamine receptors. The dopaminergic effect of lisuride, an ergot alkaloid, could not be reversed by cimetidine.
PITUITARY-THYROID RESPONSES TO SURGICAL STRESS
Authors: Chan Vivian , Wang Christina , Yeung Rose T. T. 
Published: December 2008

ABSTRACT
The effect of surgery on pituitary-thyroid function was studied in 12 euthyroid patients. There was a sharp early increase in total thyroxine level, causing displacement of triiodothyronine from thyroid hormone binding proteins resulting in the elevation of the biologically more potent free triiodothyronine fraction. The serum triiodothyronine concentration fell rapidly during and after the operation, with a concomitant rise in reverse triiodothyronine level. Increased prolactin levels were found during and after surgery. With no post-operative complication, recovery of normal pituitary-thyroid function occurred after 4 to 7 days of convalescence.
FACTORS AFFECTING THE β-CELL SENSITIVITY TO ALLOXAN IN VIVO
Authors: Boquist L. 
Published: December 2008

ABSTRACT
Blood glucose and pancreatic islet morphology were studied in mice subjected to different kinds of treatment both before and after alloxan administration. d-Glucose, d-mannose, d-fructose, NaHCO3 and sodium lactate protected against alloxan when given before, but not when given after alloxan, whereas l-leucine protected when administered before, and also when injected 1 or 3 min after alloxan. No protection was seen in animals receiving l-leucine 10 min following alloxan. The findings may indicate that the mechanism for alloxan protection by 1-leucine differs from that of the other compounds tested.
LUTEOTROPHIC ACTIVITY OF ECTOPICALLY DEVELOPING RAT BLASTOCYSTS
Authors: Zeilmaker G. H. , Verhamme C. M. P. M. 
Published: December 2008

ABSTRACT
The production of a luteotrophic hormone by ectopically transplanted rat blastocysts was demonstrated by transfer of blastocysts to the kidneys of cyclic and pseudopregnant mice and isogeneic rats.
Pseudopregnancy was induced in nearly all cyclic mice bearing trophoblastic outgrowths but not in cyclic rats. In both mice and rats prolongation of pseudopregnancy was observed following ectopic transplantation of rat blastocysts at the time of normal egg implantation. It is concluded that ectopically developing rat trophoblastic tissue produces a luteotrophic hormone.
TESTICULAR BLOOD FLOW AND TESTOSTERONE CONCENTRATIONS IN THE SPERMATIC VENOUS BLOOD IN RATS WITH EXPERIMENTAL CRYPTORCHIDISM
Authors: Damber Jan-Erik , Bergh Anders , Janson Per Olof 
Published: December 2008

ABSTRACT
Testicular blood flow and testosterone concentrations in the spermatic venous plasma were measured on unilaterally cryptorchid rats. Blood flow to the cryptorchid testis was 31.4 ± 11.7 (sd) ml/100 g x min which was significantly higher than that of the scrotal testis (17.7 ± 4.4 ml/100 gx. min) Stereological analysis showed a relative increase of blood vessel containing interstitial tissue in the cryptorchid testis, which was probably the main factor responsible for the relative increase of blood flow to the cryptorchid testis. The increase of interstitial tissue was greater than the increase of blood vessels and thus, the interstitium in the cryptorchid testis contained a number of vessels which was smaller than that of the interstitium in the scrotally located testis.
The concentration of testosterone in the spermatic vein of the abdominal testis was 18.0 ± 5.5 (sd) ng/ml and the corresponding value for the scrotal testis was 41.2 ± 7.0 ng/ml. Calculations based on functional and morphological data indicate that the function of the Leydig cells in the abdominal testis was impaired. It was concluded that the outflow of testosterone from the cryptorchid testis was highly reduced.
SHORT-TERM REGULATION OF LH AND FSH SECRETION IN CYCLIC WOMEN
Authors: Römmler A. , Baumgarten S. , Schneller E. , Schwartz U. , Hammerstein J. 
Published: December 2008

ABSTRACT
The effects of six consecutive LH-RH injections (25 μg intravenously each) at 90 min intervals on serum gonadotrophin and serum ovarian steroid levels were investigated in cyclic women (n= 13) in the follicular, midcycle and luteal phase of the menstrual cycle.
The maximum response of LH pituitary reaction to repeated LH-RH injections was smallest in the follicular phase, higher in the luteal phase and greatest in the midcycle phase of the menstrual cycle. The maximum response of FSH reaction was small both in the follicular and luteal phase and again greatest in the midcycle phase.
The pituitary response pattern after six consecutive LH-RH injections also varied throughout the cycle. On the one hand there was a constant pronounced increase in the response from the first to the second LH-RH injection for both LH and FSH, while the second of all six increments (Δ2) was the maximum increment. On the other hand, for both LH and FSH the responses Δ3 to Δ6 decreased progressively in the luteal phase and showed an even further pronounced decrease in the midcycle phase, indicating an exhaustion of pituitary secretion. In the follicular phase, however, the decrease in the responses Δ3 to Δ6 for LH was small, but significant. For FSH no significant changes between the responses Δ2 to Δ6 were observed.
Secondary to the elevated gonadotrophin levels, serum levels of oestradiol, 17-hydroxyprogesterone and progesterone increased slightly in the follicular phase and distinctly in the luteal phase of the cycle.
Possible mechanisms are discussed which might provide an explanation for the observed augmentation and subsequent diminution of pituitary reaction.
MALE PROLACTIN SECRETING PITUITARY ADENOMAS IN HUMANS STUDIED BY PEROXIDASE-LABELLED ANTIBODY METHOD
Authors: Osamura R. Yoshiyuki , Watanabe Keiichi , Teramoto Akira , Hirakawa Kimiyoshi , Kawano Nobuyuki , Morii Seiji 
Published: December 2008

ABSTRACT
In order to identity the source of excess secretion of prolactin in male patients, the pituitary tumours of 11 males with hyperprolactinaemia were studied by peroxidase-labelled antibody method using antibodies against human prolactin. Using light microscope, prolactin was demonstrated in most tumour cells in all cases. Ultrastructurally, prolactin was localized mainly on the secretory granules. Immunohistochemically positive cells were thought to correlate wih first type of tumour cells which were the major component observed by regular electron microscopic study without immunohistochemical staining. These findings indicated the secretion of excess amount of prolactin by the tumour cells and were considered to be responsible for the category of Male Prolactin Secreting Pituitary Adenoma. The mechanism by which these male hyperprolactinaemic patients are endocrinologically non-functioning is also discussed.
GONADOTROPHIN REGULATION IN THE LACTATING RAT
Authors: Steger R. W. , Peluso J. J. 
Published: December 2008

ABSTRACT
Post-partum lactation in the rat is associated with follicular quiescence and an attenuation of gonadotrophin secretion. The present study demonstrates that the lactating rat responds to exogenous LH-releasing hormone (LH-RH) in a manner similar to dioestrous rats. Oestrogen priming increases the LH and FSH response to LH-RH to a smaller degree in ovariectomized, lactating, than in non-lactating, ovariectomized rats. Pituitary LH levels throughout lactation did not seem to be related to LH-RH-induced LH release. A diminished post-castration rise in both LH and FSH, and a diminished positive feedback response to oestrogen administration were also observed and may indicate a disruption of gonadotrophin regulation at both the hypothalamic and the pituitary level.
PLASMA LEVELS OF GROWTH HORMONE IN FEMALE RATS OF DIFFERENT AGES
Authors: Edén Staffan , Albertsson-Wikland Kerstin , Isaksson Olle 
Published: December 2008

ABSTRACT
Radioimmunoassayable growth hormone (GH) was determined in fed and fasted female rats of different ages. In 6–40 day-old rats blood was collected at hourly intervals in groups of rats at different time intervals during the day. Within each age group the variation in plasma GH was considerable. In 6–14 day-old rats plasma GH was generally elevated. By day 18 levels declined, lowest on day 22 and by day 26 again increasing. In 14 day-old rats the median plasma level of GH was 22 ng/ml, in 22 day-old rats < 5 ng/ml and in 40 day-old rats 43 ng/ml. In 14 day-old rats levels ranged from < 5 ng/ml – 148 ng/ml, in 22 day-old rats from < 5 ng/ml – 34 ng/ml and in 40 day-old rats from < 5 ng/ml – > 200 ng/ml. A 20 h fasting period was associated with a significant decrease in plasma GH. In 45 day-old rats, the variations in plasma GH of individual animals were studied by obtaining sequential blood samples from unrestrained, undisturbed animals with implanted intra-aortic cannulae. In these rats GH secretion was characterized by an episodic release, occurring every 2–4 h. After a 20 h fasting period major peaks were depressed and occurred less frequently. It is concluded that there is an age-related as well as a circadian rhythm in growth hormone secretion in the rat and that sequential sampling of blood is essential for the evaluation of the secretory pattern.
CHANGES OF THE HYPOTHALAMUS-PITUITARY-THYROID AXIS IN STREPTOZOTOCIN-DIABETIC RATS DURING ADAPTATION TO A LOW IODINE DIET
Authors: Montoya Eladio , González Concepción , Lamas Luis , Jolín Trinidad , González Margarita 
Published: December 2008

ABSTRACT
Studies on the hypothalamus-pituitary-thyroid axis have been carried out in control and in diabetic male Wistar rats during adaptation to a 125I-labelled low iodine diet. Diabetes was induced by a single streptozotocin injection (7 mg/100 g body weight). Thyroid weight, thyroid 127I and 125I content, [125I]iodoamino acid distribution in thyroid digests, plasma PBI, plasma and pituitary TSH and hypothalamic TRH by radioimmunoassay were measured between 5 and 30 days after saline or streptozotocin injection, corresponding to 15 and 40 days after onset of the 125I-LID. As compared to controls, diabetic animals have smaller thyroids. The 125I and 127I in diabetic thyroids between 5 and 10 days was lower than in control glands; at longer intervals both 125I and 127I increased with time in diabetics, while no remarkable changes were seen in the control glands. Furthermore, the percentage of T3 and the MIT/DIT and T3/T4 ratios in thyroids of diabetic were lower than in the corresponding control group at all intervals. These results are compatible with a deficiency of TSH stimulation and/or with a high thyroidal iodine content.
Compared to the controls, each group of diabetic rats presented a significantly lower plasma TSH concentration, in spite of the fact that its plasma PBI is more or similarly reduced in diabetic than in controls. Furthermore, the decreased pituitary TSH secretion in diabetic rats at early intervals is lower than in controls although the pituitary TSH and hypothalamic TRH remain within normal ranges. It is concluded that the decrease in pituitary TSH secretion may be the result of a reduction of pituitary TRH stimulation, secondary to a diminished secretion and/or synthesis of TRH by the hypothalamus.
IN VITRO EFFECT OF 16α-HYDROXYPROGESTERONE ON THE ENZYME ACTIVITIES RELATED TO ANDROGEN PRODUCTION IN HUMAN TESTES
Authors: Inano Hiroshi , Tamaoki Bun-ichi 
Published: December 2008

ABSTRACT
Progesterone was converted in vitro to 16α- and 17α-hydroxyprogesterones in the presence of NADPH by the testicular microsomal fraction (precipitate at 10 000 × g−105 000 × g) obtained from patients with prostatic carcinoma. 16α-Hydroxyprogesterone was not metabolized by either the microsomal or the cytosol fractions, and accumulated in the incubation medium. 16α-Hydroxyprogesterone competitively inhibited the activity of the C-17−C-20 lyase in the testicular microsomal fraction with an estimated inhibitor constant of 72 μm. Moreover, the 16α-hydroxyprogesterone non-competitively inhibited the activity of the 20α-hydroxysteroid dehydrogenase in the testicular cytosol fraction and had an estimated inhibitor constant of 52.9 μm. Other testicular enzymes related to steroid metabolism, such as Δ5-3β-hydroxysteroid dehydrogenase coupled with the Δ4-Δ5 isomerase, 16α-hydroxylase, 17α-hydroxylase and 17β-hydroxysteroid dehydrogenase were not influenced in vitro by 16α-hydroxyprogesterone at the concentration of 0.1 mm. From these findings, it is concluded that 16α-hydroxyprogesterone inhibit specifically the cleavage of the side-chain of 17α-hydroxypregnenes in the course of androgen formation from pregnenolone in vitro.
DISSOCIATION OF PLASMA AND CSF PROLACTIN HETEROGENEITY
Authors: Jordan Richard M. , Kendall John W. 
Published: December 2008

ABSTRACT
Plasma and cerebrospinal fluid (CSF) specimens from 3 patients with suprasellar extension of a pituitary tumour were fractionated by column chromatography. "Big" and "little" prolactin were found in plasma but only "little" prolactin was found in CSF. Prolactin containing CSF from 2 of the patients was incubated with prolactin-free plasma and chromatographed. The elution patterns demonstrated a striking shift toward the [1251] albumin marker resembling the "big" and "little" prolactin pattern seen in native plasma. In addition, [125I]h prolactin was incubated with prolactin-free plasma and rechromatographed. A substantial early eluting peak of radioactivity occurred in the zone of albumin elution. The presence of only "little" prolactin in CSF and the conversion of CSF "little" prolactin to "big" prolactin by exposure to plasma suggest that "big" prolactin is not a prohormone but results from binding of "little" prolactin to plasma proteins or aggregation of "little" prolactin in the presence of plasma.
THE INFLUENCE OF CHRONIC RENAL FAILURE ON SERUM AND URINARY THYROID HORMONE LEVELS
Authors: Kølendorf Klaus , Møller Birger Broch , Rogowski Preben 
Published: December 2008

ABSTRACT
The effects of various degrees of chronic renal failure on serum and urinary thyroid hormones were studied in 10 patients with a mean creatinine clearance (Cr.Cl.) of 23 ml/min (group A), in 11 patients with a Cr.Cl. of 5.7 ml/min (group B), and in 60 healthy euthyroid subjects with normal renal function. We found a significant decrease (P < 0.01) of serum total thyroxine (T4) (5.3 ±1.9 (sd) μg/100 ml in group A and 4.1 ± 1.5 in group B), serum total triiodothyronine (T3) (65.4 ± 17.4 ng/100 ml ~57.4 ± 13.9), serum free T4 (5.60 ± 1.74 arb.U ∼ 4.45 ± 1.61), and serum free T3 (69.51 ± 21.22 arb.U ∼ 62.09 ± 12.39). T3 uptake test and basal thyroid stimulating hormone (TSH) values were normal in both groups of renal patients.
No statistical significance was found in T4 excretion in urine. Urinary T3 excretion was significantly reduced (P < 0.01) in group A (27 ± 44 ng/24 h), and undetectable in terminal renal failure. Urinary protein excretion was non-selective and low (median 0.2 g/24 h and 0.7 g/24 h, respectively).
Conclusively we have found reduced levels of serum total and free T3, and in contradiction to most investigators substantially reduced levels of serum total and free T4. Urinary excretion of T4 and T3 reflects the low levels of free serum hormones and the tubular impairment.
NEUROTRANSMITTER CONTROL OF THYROTROPHIN SECRETION IN HYPOTHYROID RATS
Authors: Männistö P. T. , Ranta T. 
Published: December 2008

ABSTRACT
The effect of drugs modifying dopaminergic, noradrenergic and serotonergic systems on the serum TSH levels was studied in the male rats made hypothyroid by giving 10 mg/l of propylthiouracil in tap water for 4 days. Apomorphine (2.5 mg/kg, given once −30 min before sacrifice; or four times −120, 90, 60 and 30 min before sacrifice), bromocryptine (10 and 20 mg/kg, 2 h before sacrifice) and piribedil (50 and 100 mg/kg, 4 h) decreased the serum TSH concentrations. The effect of a single dose of apomorphine (2.5 mg/kg, 30 min before sacrifice) was partially reversed by a pimozide pre-treatment (2.5 mg/kg, 2 h). Clonidine (1 mg/kg but not 0.01 or 0.1 mg/kg, 2 h before sacrifice) further elevated the high TSH levels whereas α-methyl-p-tyrosine (300 mg/kg, 2 h), phenoxybenzamine (50 mg/kg, 2 h) and diethyldithiocarbamate (300 mg/kg, 2 h) significantly decreased TSH secretion. The effect of clonidine (1 mg/kg, 2 h) was partially antagonized by phenoxybenzamine (20 mg/kg, 2 h). A high dose of 5-HTP (300 mg/kg, 2 h) increased serum TSH concentrations whereas p-chlorophenylalanine (100 mg/kg, 2 h) decreased it. When both drugs were given together, the serum TSH levels did not change. L-tryptophan (100–300 mg/kg, 2 h) uniformly decreased the serum TSH concentrations in all experiments. It is concluded that in the hypothyroid rats, the secretion of TSH is inhibited by dopaminergic system, and stimulated by noradrenergic system. The effect of 5-HT pathways remained an open question.