bluuebunny/crossref_metadata_2025_split huggingface dataset:
CHARACTERISTICS OF THE CYCLIC 3′, 5′-AMP FORMATION IN ISOLATED OVARIAN FOLLICLES FROM PMSG-TREATED IMMATURE RATS AFTER STIMULATION IN VITRO WITH GONADOTROPHINS AND PROSTAGLANDINS
Authors: Nilsson Lars , Rosberg Sten , Ahrén Kurt 
Published: December 2008

ABSTRACT
Isolated pre-ovulatory follicles from PMSG-injected immature rats, described in a previous publication, have been used for the investigation of the pattern of cyclic 3′,5′-AMP synthesis after in vitro addition of gonadotrophins and prostaglandins. The follicles were incubated in a modified Krebs bicarbonate buffer for periods up to 4 h and the cyclic 3′,5′-AMP content in tissue and medium was analyzed with the protein binding assay of Gilman (1970).
Addition of LH, FSH or prostaglandin E2 (PGE2) increased the cyclic 3′,5′-AMP level in follicular tissue dramatically. HCG and TSH, but not STH or prolactin, also induced a similar increase. The effect of FSH was blocked by a highly specific antiserum to LH. The effect of LH had a maximum after approximately 1 h of incubation, whereas the maximal effect of PGE2 was seen between 5 and 15 min of incubation. When LH was present in the incubation medium a significant release of cyclic 3′,5′-AMP into the medium occurred. Theophylline potentiated the effects of LH and PGE2.
The different time-courses of the effects of LH and PGE2 on the cyclic 3′,5′-AMP production by follicular tissue are discussed in relation to the hypothesis of prostaglandins as obligatory mediators of all LH effects on the ovary (Kuehl et al. 1970).
OVARIAN SECRETION RATES OF OESTROGENS, ANDROGENS AND PROGESTERONE IN NORMAL WOMEN AND IN WOMEN WITH PERSISTENT OVARIAN FOLLICLES
Authors: de Jong F. H. , Baird D. T. , van der Molen H. J. 
Published: December 2008

ABSTRACT
The concentrations of oestradiol-17β, oestrone, androstenedione, testosterone, dehydroepiandrosterone, dehydroepiandrosterone sulphate and progesterone were measured in ovarian venous plasma from one or both ovaries in 4 normal women during different stages of the menstrual cycle and in 4 women with persistent ovarian follicles. In addition the steroid concentrations in peripheral plasma and follicular fluid were estimated. All steroids mentioned, with the exception of dehydroepiandrosterone sulphate, were secreted by the ovaries. The concentrations of oestradiol-17β, oestrone, androstenedione and progesterone were higher in the venous plasma from the ovary containing the developing follicle or corpus luteum than in venous plasma from the contralateral ovary. There was a good correlation between ovarian secretion of the oestrogenic steroids and androstenedione.
Finally, the quantitative contribution of the ovarian secretion to the blood production rates of the androgens and progesterone was calculated. The only contributions exceeding 20 % of the blood production rate were those of progesterone and androstenedione during the second half of the cycle.
EVIDENCE FOR A SEPARATE ADENYLATE CYCLASE SYSTEM RESPONSIVE TO BETA-ADRENERGIC STIMULATION IN THE RENAL CORTEX OF THE RAT
Authors: Bell Norman H. , Fleming John , Benedict Joanne , Pantzer Lisa 
Published: December 2008

ABSTRACT
Previous studies in other laboratories had indicated that some of the effects of parathyroid hormone on skeletal tissue and the renal tubule to influence ion metabolism can be produced by beta-adrenergic stimulation. Studies were carried out to determine whether the same adenylate cyclase system in rat renal cortex is activated by parathyroid hormone and isoproterenol. At maximal effective concentration of dose response, parathyroid hormone (2 × −5 m) increased adenylate cyclase activity by some 415 per cent, isoproterenol (10−6 m) increased activity by some 40 to 50 per cent, vasopressin (10−5 m) increased activity by some 96 per cent and porcine calcitonin (10−5 m) increased activity by some 92 per cent. Dl-propranolol (10−5 m), a beta-adrenergic receptor blocking agent, prevented the increase in enzyme activity produced by isoproterenol (10−6 m), did not diminish the increase in activity produced by parathyroid hormone (10−6 m) and did not influence basal adenylate cyclase activity by itself. The combined maximal concentrations of isoproterenol together with either parathyroid hormone, vasopressin or porcine calcitonin were additive. These results indicate that there is an adenylate cyclase system in rat renal cortex which can be activated by beta-adrenergic stimulation with isoproterenol, and is separate from the systems responsive to parathyroid hormone, vasopressin or calcitonin.
EFFECT OF OESTRADIOL BENZOATE ON PITUITARY AND TESTIS FUNCTION IN THE NORMAL ADULT MALE RAT
Authors: Verjans H. L. , de Jong F. H. , Cooke B. A. , van der Molen H. J. , Eik-Nes K. B. 
Published: December 2008

ABSTRACT
The effects of subcutaneous administration of oestradiol benzoate (EB) on the weights of sex organs and on levels of testosterone and gonadotrophins in normal adult male rats have been studied. Doses of EB varied from 0.01 to 100 μg and were administered daily for seven days. Administration of 100 μg EB resulted in suppression of pituitary LH, while serum LH levels were already decreased after treatment with EB ≧ 1 μg. Pituitary and serum FSH levels were suppressed after administration of 100 and 10 μg EB respectively. Testicular tissue and serum levels of testosterone decreased after treatment with amounts of EB ≧ 1 μg. These decreased androgen levels were also reflected in a concomitant decrease in the weights of the ventral prostate and seminal vesicles. A decrease in the weight of the testes was obtained following a dose of EB ≧ 10 μg.
AN IMPROVED IN VITRO BIOASSAY METHOD FOR MEASURING LUTEINIZING HORMONE (LH) ACTIVITY USING MOUSE LEYDIG CELL PREPARATIONS
Authors: Van Damme M.-P. , Robertson D. M. , Diczfalusy E. 
Published: December 2008

ABSTRACT
An improved in vitro bioassay method for the measurement of LH activity is presented. The method is based on the assay of testosterone produced by "Leydig cell" preparations from mouse testes in the presence of added gonadotrophin. The method is significantly improved in terms of sensitivity, precision and practicability when compared to the previously described bioassay method employing decapsulated testes from adult mice. The sensitivity of the improved method is 15 μIU for HCG and 50 μIU for HMG. The useful range of the method is 15–260 μIU for HCG and 50–900 μIU for HMG. Using a 3 + 3 point assay design with each dose in quadruplicate, a mean index of precision (λ̅) of 0.044 was obtained in 19 assays.
Human FSH, TSH, ACTH, LTH, STH, oxytocin, vasopressin and LHRH preparations did not influence the bioassay method at levels likely to be found in biological samples. A good correlation was found between estimates obtained by the "Leydig cell" method and by the method using decapsulated testes when various HCG and HMG preparations were used. With the proposed method at least 30 samples can be assayed each week by 2 persons, with a marked reduction in cost.
DECREASED ARGININE-INDUCED HGH RESPONSE DURING L-DOPA THERAPY IN PARKINSONIAN PATIENTS
Authors: Johnson S. E. , Norman N. , Sjaastad O. 
Published: December 2008

ABSTRACT
A study has been carried out in 8 patients with Parkinson's disease in order to measure the growth hormone response to arginine before treatment with L-DOPA and during such treatment. A significant lowering of the HGH response was found during treatment.
PRODUCTION AND EVALUATION OF GLUCAGON ANTIBODIES FOR RADIOIMMUNOASSAY
Authors: Holst J. J. , Aasted B. 
Published: December 2008

ABSTRACT
Antiglucagon antibodies were raised in rabbits against glucagon covalently linked to bovine serum albumin. We followed three different immunization schemes in order to investigate the role of immunization frequency. The animals were bled regularly and their sera analysed for titre, avidity, and specificity of glucagon antibodies. Immunization frequency could not be correlated to any of the parameters investigated. Antigen dose, however, and persistence of immunization seem to be of importance. After 9 months 22 out of 30 animals immunized yielded antisera with an avidity suitable for radioimmunoassay. Nine of these antisera could be diluted to more than 1:96 000, 8 yielded detection limits below 25 pg/ml, 4 were relatively specific for pancreatic glucagon, and 5 reacted equally well with pancreatic and gut glucagon.
GONADAL FACTORS REGULATING THE ACTIVITY OF THE 17β-HYDROXYSTEROID OXIDOREDUCTASE IN RAT LIVER
Authors: Thaler-Dao H. , Breuer H. 
Published: December 2008

ABSTRACT
The activity of the 17β-hydroxysteroid oxidoreductase (17β-HSOR), catalysing the oxidoreduction of oestradiol-17β and oestrone, has been studied in the cytosol fraction of rat liver under various conditions. The activity of the enzyme increased during maturation and reached a plateau at 100 days in females and at 180 days in males. In adult male rats, the activity of the 17β-HSOR was about 60% higher than in adult female rats. When female animals were castrated, the development of enzyme activity was similar to that observed in male rats; there was no difference in enzyme activity between adult castrated female rats and normal male rats. In normal female rats the activity of the 17β-HSOR was high during metoestrus and dioestrus, and low during pro-oestrus and oestrus. These findings show that oestrogens have a repressing effect on the activity of a key enzyme of steroid metabolism in rat liver.
LH AND FSH IN SERUM AFTER INTRAMUSCULAR ADMINISTRATION OF LH/FSH-RELEASING HORMONE IN NORMAL AND HYPOGONADAL MEN
Authors: Jørgensen F. Schønau , Kampmann J. , Micic S. , Roos J. , Johnsen Svend G. 
Published: December 2008

ABSTRACT
The increase in serum concentrations of LH and FSH after intramuscular administration of LH/FSH-RH was investigated in normal and hypogonadotrophic hypogonadal males. LH and FSH were measured by specific radio-immunoassays. To evaluate the appropriate dose of LH/ FSH-RH for intramuscular administration different doses were administered and with 200 μg an increase in LH and FSH was found comparable to the results obtained by other investigators using intravenous administration. After the initial studies a simple test including two determinations before LH/FSH-RH administration and one 60 min and 120 min after administration was developed and used in all cases. In 12 normal males a significant increase in the serum concentration of both LH and FSH was found averaging 381 % and 148 % respectively 60 min after 200 μg LH/FSH-RH with a slight decrease in LH but not in FSH after 120 min. A positive response similar to that in normal men was observed in 11 hypogonadotrophic hypogonadal patients presenting different clinical pictures. This indicates that in all these patients the hypogonadotrophic state was due to a hypothalamic defect and not to a hypophyseal disorder.
THYROXINE DISSOCIATION IN HUMAN PLASMA: MEASUREMENT OF ITS RATE BY A CONTINUOUS-FLOW DIALYSIS METHOD
Authors: Hillier A. P. 
Published: December 2008

ABSTRACT
A method is described for measuring the rate at which thyroxine dissociates from binding proteins in human plasma. The method depends upon the fact that free thyroxine is able to diffuse through Visking dialysis membrane whereas bound thyroxine cannot. At 20°C half of the plasma thyroxine dissociates within about 200 seconds and 75% within 10 min. At 37°C half of the hormone dissociates in less than 20 seconds and the reaction is virtually complete in 3–4 min. These values agree well with those previously obtained by a resin-uptake method. In the Discussion it is calculated that the pool of free thyroxine in the plasma is replenished about 5 × 106 times each day and that an individual thyroxine molecule spends only about 15 mseconds in free solution during each transit.
INTERACTION OF CONTRACEPTIVE PROGESTINS AND RELATED COMPOUNDS WITH THE OESTROGEN RECEPTOR
Authors: van Kordelaar M. G. , Broekman M. M. M. , van Rossum J. M. 
Published: December 2008

ABSTRACT
The distribution pattern of oestradiol in ovariectomized rats as a function of time has been studied following intravenous administration of the tritiated hormone. Oestrogen specific binding with limited capacity was observed in the uterus, vagina, anterior pituitary, adrenals, preoptic area, hypothalamus, amygdala, septum and tractus diagonalis. Maximal uptake of oestradiol in the pituitary occurred within 5 min, in the uterus 60 min after injection, and remained almost unchanged at this level for more than two hours. The binding capacity per mg tissue decreased in the order pituitary, uterus, vagina, preoptic area, adrenals, hypothalamus, amygdala, septum and tractus diagonalis.
The hormone concentration in these tissues one hour after [3H]oestradiol injection was lowered by previous administration of ethinodiol, norethinodrel, lynestrenol and norethindrone, whereas medroxyprogesterone, chlormadinone, megestrol and methyllynestrenol had no effect. The same results were obtained, when instead of the steroid alcohols the corresponding acetate esters were administered. For norgestrel, oestrenol and nortestosterone the effect in the dose range studied was limited to the pituitary and preoptic area.
For lynestrenol the inhibition of oestradiol binding in the target tissues was almost the same when the progestin was given 60 and 5 min before oestradiol, whereas in the case of administration 30 min after oestradiol no inhibition was observed. The reduction of oestrogen binding appeared to be dose-dependent, but the dose required to obtain a certain effect for the uterus was four times as high as for the pituitary.
Discrepancies between previous studies and the implications of the present findings for the mechanism of action of ovulation inhibition by these progestins are discussed.
INTERACTION OF CONTRACEPTIVE PROGESTINS AND RELATED COMPOUNDS WITH THE OESTROGEN RECEPTOR
Authors: van Kordelaar J. M. G. , Vermorken A. J. M. , de Weerd C. J. M. , van Rossum J. M. 
Published: December 2008

ABSTRACT
Incubation of the 105 000 × g supernatant of rat uterus homogenate with [3H] oestradiol resulted in an oestrogen specific binding of limited capacity to a macromolecule sedimenting in the 8–9S region after density gradient centrifugation. The contraceptive progestins of the 19-nortestosterone series were able to interfere with oestradiol binding in contrast to the hydroxyprogesterone derivatives chlormadinone, medroxyprogesterone and megestrol. The interaction appeared to be competitive. The strongest inhibition of oestradiol binding was observed in the presence of ethinodiol, followed by norethinodrel, lynestrenol and norethindrone respectively. Norgestrel was almost inactive. Of the related structures tested oestrenol displayed more activity than norethindrone, nortestosterone and ethisterone were less active and 6α-methyllynestrenol showed only border-line activity.
In comparison with norethinodrel and norethindrone, lynestrenol and oestrenol appeared in vitro to be stronger competitors for oestradiol than in vivo (Part I; Van Kordelaar et al. 1975). This may be due to the great difference in lipophilic character, which is reflected in the RM values of these compounds.
From the results obtained it may be concluded, that the presence of a 17α-ethynyl substituent promotes receptor binding, whereas the introduction of methyl substituents in the positions 6, 10 and 18 causes the opposite effect. The relationship between the various ring A structures and the affinity to the receptor is discussed.
URINARY GONADOTROPHINS IN THE SERTOLI-CELL-ONLY SYNDROME
Authors: Christiansen Peter 
Published: December 2008

ABSTRACT
In order to study the hypophyseal-testicular axis in males with complete absence of germinal epithelium, the urinary total hypophyseal gonadotrophins (HG), urinary follicle stimulating hormone (FSH) and urinary luteinizing hormone (LH) were measured by specific bioassays in 12 males with classical Sertoli-cell-only syndrome and compared with HG, FSH and LH in normal and castrated men. HG and FSH were significantly higher than HG and FSH in normal men (P < 0.0025, P < 0.0005, respectively), but significantly lower than in castrated men (P < 0.001, P < 0.01, respectively). LH was not different from LH of normal men, but significantly lower than in castrated men (P < 0.0005). All patients had normal excretion of androgen metabolites (androsterone + aetiocholanolone) but a dexamethasone suppression test, performed in 8 subjects, revealed that in 2 cases of testicular origin, the values were below the normal range. The excretion of oestrogens was within the normal range.
The presented data support the concept that the germinal epithelium produces a substance capable of inhibiting FSH secretion from the hypophyses, the Sertoli cell itself, however, having a basal production of this inhibitor. The finding of low excretion of testicular androgen metabolites in some of the patients and normal urinary LH, indicates that disturbances in the LH – testosterone feedback mechanism in such patients may occur and that the previous concept of isolated defects of spermatogenesis in all such patients was erroneous.
INFLUENCE OF PROGESTERONE ON THE MITOCHONDRIAL SIZE IN THE UTERINE GLANDS OF THE RAT, MOUSE, HAMSTER, AND GUINEA-PIG
Authors: Nilsson Ove 
Published: December 2008

ABSTRACT
The administration of progesterone produced giant mitochondria in the gland cells of the rat uterus but not in those of the mouse, hamster, and guinea-pig uteri. Chloramphenicol did not impede the appearance of the giant mitochondria. The implication of the differential response of the mitochondria is not yet known.
EFFECT OF LONG-TERM TESTOSTERONE OENANTHATE ADMINISTRATION ON MALE REPRODUCTIVE FUNCTION: CLINICAL EVALUATION, SERUM FSH, LH, TESTOSTERONE, AND SEMINAL FLUID ANALYSES IN NORMAL MEN
Authors: Mauss J. , Börsch G. , Bormacher K. , Richter E. , Leyendecker G. , Nocke W. 
Published: December 2008

ABSTRACT
The effect of long-term testosterone administration on male reproductive function has been investigated in seven healthy young men age 20 to 27 years. Testosterone oenanthate (TOe) was administered in doses of 250 mg per week for 21 weeks. No toxic side-effects were observed. Libido, sexual potency, frequency of sexual intercourse and body hair development generally remained unaffected, but there was a reversible mean weight gain of 3.6 kg during TOe administration. Seminal fluid parameters and radioimmunoassayable serum FSH, LH, testosterone, and androstenedione levels were monitored before, during, and after TOe administration. The serum testosterone rose approximately by a factor of two, while the serum FSH and LH were rapidly suppressed after the initiation of the TOe therapy. The mean sperm concentration fell to values below three million spermatozoa per ml, and changes in sperm motility, the percentage of normal sperm morphology, and seminal fructose concentrations generally paralleled those of the mean sperm concentrations. In contrast, the mean seminal fluid volume and serum androstenedione levels did not change significantly during TOe administration. The mean sperm concentration showed a marked recovery 13 to 16 weeks after TOe withdrawal, but sperm counts remained below pre-treatment levels in three out of seven subjects 25 to 28 weeks after discontinuation of TOe.
PHOTOPERIODIC CONTROL OF LH RELEASE IN THE RAM
Authors: Pelletier J. , Ortavant R. 
Published: December 2008

ABSTRACT
The influence of variations in the duration of light photoperiod on LH release has been studied in intact and castrated rams submitted to a 6 months "annual" light rhythm. Blood was collected once a month and the plasma LH levels were determined by radioimmunoassay. In intact rams, the LH level is decreased when the light photoperiod is increased, but as soon as this photoperiod begins to decrease, a sharp increase (about 80%) in the LH level is observed. Thereafter a slow decline in plasma LH occurs until the photoperiod reaches a minimum. In the castrated animals, the plasma LH level is three to four times higher than in the intact animals but the pattern of the variations with regard to the light photoperiod duration, is essentially the same. Thus an increase of 59 and 43 % in plasma LH occurs in the two breeds used when the light photoperiod begins to decrease.
These results indicate that hypothalamo-hypophyseal activity is modulated by gradual changes in the duration of light photoperiods either in the presence or absence of androgens.
MEASUREMENT OF RAT LH WITH A DOUBLE-ANTIBODY SOLID-PHASE RADIOIMMUNOASSAY: EFFECT OF LH-RH AND OF TESTOSTERONE OENANTHATE IN CASTRATED ANIMALS
Authors: Dericks-Tan J. S. E. , Taubert Hans-Dieter 
Published: December 2008

ABSTRACT
A double-antibody solid-phase radioimmunoassay for the measurement of rat LH was described. The use of a solid-phase method for the second incubation resulted in a considerable saving of time as compared to the conventional double-antibody method. The sensitivity and accuracy of the method were not affected by this modification. It was found that there was a cross-reaction between the NIAMD-anti-rat-LH-serum-1 used and NIAMD-rat-FSH-RP-1. This indicates that the test system does not specifically measure rat LH but gonadotrophic activity.
The RIA was tested under different experimental conditions. In male rats, the effect of castration and of subsequent treatment with testosterone oenanthate upon serum LH, and upon the weight of the seminal vesicles, the ventral prostate, and the levator ani, was examined. Serum LH rose rapidly after castration and reached 2 to 4 weeks after orchidectomy a maximum (8–9 fold increase). Subsequent treatment with testosterone oenanthate caused a rapid decrease of serum LH. The accessory sex organs showed reciprocal changes of weight.
In oophorectomized rats whose pituitaries had been blocked with oestradiol monobenzoate and progesterone, a linear log-dose response of plasma LH was found after administration of various doses of synthetic LH-RH.
STIMULATION WITH THYROTROPHIN-RELEASING HORMONE (TRH) DURING ANTITHYROID TREATMENT
Authors: Lauridsen Ulrik Birk , Kirkegaard Carsten , Friis Thorkild , Siersbæk-Nielsen Kaj 
Published: December 2008

ABSTRACT
During antithyroid treatment a total of 88 TRH tests was performed in 56 clinical euthyroid patients. 56 % had negative response to TRH (i. e. Δ TSH < 2 μU/ml) after being treated in average 12.6 months and no relation between the duration of treatment and the outcome of the TRH test was found. In the group with positive TRH tests (i. e. Δ TSH > 2 μU/ml) the mean T4 value was slightly decreased (5.8 ± sd 2.5 μg/100 ml) while the mean T3 value was normal (121 ± sd 32 ng/100 ml). The group with negative TRH tests had quite normal serum T4 values (9.3 ± sd 3.1μg/100 ml) but in general high normal or elevated serum T3 values (175 ± sd 31 ng/100 ml). Our results seem to indicate that serum T3 is of greater importance than serum T4 with regard to the outcome of the TRH test. The majority of the cases with negative TRH tests, however, had serum T3 and T4 values within normal range. In almost all patients with a negative TRH test a negative T3 suppression of 131I uptake in the thyroid gland was found while a positive TRH test was not correlated with suppressibility of 131I uptake.