bluuebunny/crossref_metadata_2025_split huggingface dataset:
IN VITRO STEROID SYNTHESIS BY FOETAL RABBIT ADRENALS
Authors: Kurachi K. , Miyazaki M. , Mori H. , Matsumoto K. 
Published: December 2008

ABSTRACT
Adrenal tissue homogenates from foetal rabbits in late gestation and their mothers were incubated with [7α-3H] pregnenolone and analyzed for conversion products by reverse isotope dilution procedures. Deoxycorticosterone and corticosterone were synthesized as main products by foetal as well as by adult adrenals. In addition, small amounts of progesterone, 17-hydroxypregnenolone and cortisol were formed by both adrenals. No C19-steroids and 16α-hydroxysteroids could be found. The results indicate a similarity in the qualitative metabolic pattern of pregnenolone by adrenal cortical tissue of late gestation rabbit foetuses to that of adult rabbits. However, the activity of 3β-hydroxysteroid dehydrogenase per gram tissue in the foetal rabbit adrenal was of the order of one tenth that in the adrenals of their mothers. By using [3H] progesterone as substrate, the activities of 21-hydroxylase and 11β-hydroxylase in the foetal adrenal were similarly demonstrated to be less than that of the adrenal of the mother.
EFFECT OF ANDROGENS AND ANABOLIC STEROIDS ON THE PLASMA DISAPPEARANCE CURVE AND THE DISTRIBUTION OF [1,2-3H CORTICOSTERONE IN THE RAT
Authors: Linèt O. , Lomen P. 
Published: December 2008

ABSTRACT
Adult male rats were treated with daily doses (per 100 g of body weight) of 1 mg testosterone propionate (TP), 1 mg 19-nortestosterone phenylpropionate (NTPP), 2 mg methyltestosterone, 2 mg methandrostenolone, or 2 mg stanozolol for 7 consecutive days. Other groups of rats were either castrated or castrated and treated with TP. No differences could be detected between the control and experimental groups with regard to plasma levels of endogenous corticosterone 24 hours after the last doses had been administered. All experimental approaches enhanced the plasma half-life of [1,2-3H] corticosterone. The distribution volume of labelled corticosterone decreased after parenteral TP and NTPP, but increased after oral methandrostenolone and stanozolol. Castration increased the distribution volume but administration of TP to castrated animals normalized this value.
Administration of NTPP, methandrostenolone or TP to intact rats for 7 days did not influence the adrenal weight, adrenal corticosterone content, corticosterone level in the adrenal vein plasma, corticosterone secretion rate or the adrenal blood flow.
STUDIES ON GROWTH HORMONE SECRETION II. STIMULATION BY PROSTAGLANDINS IN VITRO
Authors: Hertelendy F. 
Published: December 2008

ABSTRACT
Hemisected rat anterior pituitaries were incubated in KRB (pH 7.4) containing glucose (1 mg/ml) and BSA (1 mg/ml) and the release of growth hormone (GH) was measured by radioimmunoassay. Prostaglandin E1 and E2 (1 μg/ml each) increased GH concentration in the medium by 298 % and 266 % respectively over controls during a one-hour incubation period. On molar basis prostaglandins proved to be at least a thousand times more potent stimulants of GH secretion than theophylline or dibutyryl cyclic AMP. This response was drastically reduced by preincubating the pituitary explants in the presence of EGTA in a calciumfree medium. Addition of calcium (1 mm) restored the relative GH response to PGE1 though the absolute amount of GH released was considerably less than that observed without EGTA treatment. Hormone secretion was potentiated by high concentration of K+ (54 mm) which in itself significantly stimulated GH release. 2,4-Dinitrophenol almost completely abolished PGE1 stimulated GH release indicating that the latter is an energy dependent phenomenon. The possible mechanism by which prostaglandins stimulate GH secretion and the interaction of ions in the secretory mechanism are discussed.
DIE WIRKUNG VON SYNTHETISCHEM THYROTROPHIN RELEASING HORMONE AUF DIE ENTWICKLUNG EINES EXPERIMENTELLEN EXOPHTHALMUS BEIM GOLDFISCH
Authors: Wildmeister W. , Horster F. A. 
Published: December 2008

ABSTRACT
Gold-fishes (carassius auratus) were injected with synthetic thyrotrophin releasing hormone (TRH) in concentrations of 25 μg to 1000 μg/fish. TRH did not provoke endocrine exophthalmos.
IODINATED PARTICLES IN THE RAT THYROID I. A RAPID SEPARATION METHOD
Authors: Simon C. , Dang J. , Miquelis R. , Bastiani P. 
Published: December 2008

ABSTRACT
In a first step, the quantitative preparation of the whole population of iodinated particles was reinvestigated in thyroids obtained from rats maintained in an isotopic equilibrium with 125I. The maximum yield in the iodinated particles was obtained for a 0.15 m sucrose solution in 0.1 m Tris-HCl buffer pH 7. This yield was 3.5 % and 1.7 % of the total iodine content of the thyroid for rats adapted to receive 50 (group 50) and 5 μg (group 5) of iodine daily respectively. The iodinated particles of group 50 were found to be more sensitive to pH variations than those of group 5.
In a second step, a rapid method was developed to separate the whole population of iodinated particles into physiological populations (tentatively colloid droplets and secondary lysosomes). By centrifuging onto a discontinuous Ficoll gradient, three distinct iodine peaks were regularly obtained for rats of group 5 and 50 and also for other rats receiving a diet rich in iodine. For group 50, the iodine pools (127I) as measured by isotopic equilibrium were found to represent about 16% (peak 1), 25 % (peak 2) and 59 % (peak 3) of the total particulate iodine content of the gland.
The possible nature of these three populations of iodinated particles is discussed.
THE EFFECT OF IODINE DEFICIENCY AND SUPPRESSION OF TSH SECRETION ON RADIOIODINE LABELLED THYROXINE AND TRIIODOTHYRONINE IN THE THYROID OF RATS
Authors: Emrich D. , zur Mühlen A. v. , Burmeister G. , Zimmermann H.-D. , Beckmann R. 
Published: December 2008

ABSTRACT
It has been suggested that TSH stimulation of the thyroid gland is accompanied by an alteration in the ratio of newly synthesized thyroxine (*T4)1)/triiodothyronine (*T3) in favour of *T3. Evidence in support of this hypothesis is provided here by the finding that suppression of TSH secretion in rats alters this ratio in the other direction, i. e. in favour of *T4.
Thus, endogenous TSH stimulation was increased for 4 weeks by iodine deficiency. Its suppression was performed by the administration of T3, using a dose of 0.05-0.25 μg/100 g body weight which was injected subcutaneously every 12 hours for three days. The effect of TSH stimulation and suppression could be assessed from the following parameters: thyroid weight and histology, thyroid 131I uptake, 131I conversion ratio, hormonal iodine concentration, and TSH level in the plasma. After iodine deficiency the ratio of *T4/*T3 in the thyroid gland changed in favour of *T3. This may compensate for the iodine deficiency, since the oxygen consumption and the heart rate of the animals remained in the normal range. After suppression the ratio of *T4/*T3 changed in the opposite direction, i. e. in favour of *T4. The extent of the suppression of *T4 and *T3 was dependent on the suppression dose used.
UPTAKE OF TRITIATED LYSINE-VASOPRESSIN BY ISOLATED SECRETORY GRANULES FROM BOVINE NEUROHYPOPHYSES
Authors: Vilhardt Hans 
Published: December 2008

ABSTRACT
A subcellular fraction containing neurosecretory granules was obtained by differential centrifugation of homogenized neural lobes of bovine hypophyses. The isolated granules were incubated with tritium labelled lysine-vasopressin and the uptake of the radioactive hormone by the granules was studied.
Since enzymes capable of breaking down vasopressin were present in the fraction, it was necessary after the incubation to separate the labelled vasopressin from its radioactive breakdown products. This was done by paper chromatography.
The results showed that vasopressin readily reached a higher concentration in the granules than in the surrounding medium. This process was not changed by cold, N2 or metabolic inhibitors. During the incubation radioactivity soon appeared in the proteins of the granules.
INFLUENCE OF GONADAL HORMONES ON THE ACTION OF CALCITONIN IN THE RAT
Authors: Serensen O. Helmer , Hindberg Inge 
Published: December 2008

ABSTRACT
The influence of short-term and long-term treatment with gonadal hormones on the response to calcitonin was investigated in the rat. Oestrogen-treatment, short-term as well as long-term, resulted in a reduced responsiveness to calcitonin. Long-term treatment with androgens enhanced the hypocalcaemic effect of calcitonin in castrated rats of either sex, but reduced the effect in intact animals. No sex differences could be registered in the sensitivity to calcitonin, when intact animals were compared according to age, while marked differences were observed, when the animals were compared according to weight. There was a linear decrease in the response to calcitonin with increasing age in rats of both sexes. An intraperitoneal calcium load was followed by an acute rise in the serum calcium levels. The adult animals counteracted the hypercalcaemia more slowly than the young ones. Significant differences also occurred between male and female rats, the rise in the serum calcium concentration being much more pronounced in the latter group. The hypocalcaemic activity of thyroid tissue from rats of both sexes and of various ages showed considerable variations, but no differences correlated to age or sex.
STUDIES ON THE BIOSYNTHESIS OF TESTOSTERONE IN THE RAT
Authors: Kniewald Z. , Zanisi M. , Martini L. 
Published: December 2008

ABSTRACT
Plasma levels of testosterone have been measured in adult male Sprague-Dawley rats using a gas-chromatographic procedure. Immediately after castration, the concentrations of testosterone in the plasma increase to reach a maximum one hour after orchidectomy; after this time a progressive decrease in plasma testosterone is observed. The concentration of testosterone then returns to levels close to those found before the operation two hours after castration; four hours after orchidectomy plasma testosterone begins to decrease to values lower than in the intact controls. Adrenalectomized animals with their testes in situ show a sharp decrease in plasma testosterone which begins immediately after the operation; the plasma testosterone reaches levels significantly lower than those in the intact control one hour after adrenalectomy; a greater decrease is observed four hours after the operation. Twenty-four hours after unilateral adrenalectomy the remaining gland significantly increases in weight; at this time, the plasma corticosterone and plasma testosterone levels of unilaterally adrenalectomized rats are normal. These results are interpreted as indicating that the adrenal gland of normal male rats is capable of producing testosterone, and that the synthesis of testosterone at the adrenal level is increased immediately after castration. Moreover it is suggested that the adrenal gland also contributes to the biosynthesis of testosterone in an indirect fashion, i. e. by providing the testes with an essential precursor. It has been tentatively proposed that progesterone might be such a precursor.
STUDIES ON THE INTERACTION OF LONG-ACTING THYROID STIMULATOR (LATS) WITH SOLUBLE THYROID FRACTIONS
Authors: Amino N. , Miyai K. , Azukizawa M. , Kumahara Y. 
Published: December 2008

ABSTRACT
The specificity, stability and reversibility of the in vitro interaction of LATS with soluble human thyroid fractions was studied. With regard to tissue specificity, the cell sap obtained from human liver, spleen, kidney, and muscle did not inhibit the LATS activity while the same amount of thyroid cell sap significantly inhibited it. When the LATS inhibitory activity in thyroid subcellular fractions was compared, the microsomal fraction was more active than cell sap or solubilized microsomes in terms of milligram of protein, but the cell sap had considerable activity as based on the original thyroid weight. Lyophilization of cell sap did not reduce the LATS inhibitory activity, but treatment with 2 m NaSCN and 6 m urea apparently destroyed this capacity. Acid treatment of cell sap at pH 2.5 and at 3.0 completely destroyed its ability to inhibit LATS activity. Inhibition of LATS activity was roughly proportional to the amount of thyroid cell sap. Human TSH, on the other hand, was not inhibited by cell sap which had a significant inhibitory effect on LATS. LATS activity was more effectively inhibited when a mixture of LATS-IgG and thyroid cell sap was incubated for 96 hours than for 12 hours. The inhibition of LATS activity by thyroid cell sap was partially but significantly reversed by acid treatment, as observed in experiment using microsomes. When thyroid cell sap was fractionated by gel filtration on Sepharose 4B, LATS inhibitory activity was distributed in all the fractions including the 27S to 4S proteins. In DEAE-cellulose column chromatography, LATS inhibitory activity tended to be eluted at a higher ionic strength. In each fraction of Sepharose 4B and DEAE-cellulose, LATS inhibitory activity was found to be unrelated to the thyroglobulin content.
It is believed that the inhibition of LATS activity by thyroid cell sap is compatible with an antigen-antibody reaction and that the LATS inhibitor may not be a thyroglobulin itself but a more negatively charged heterogeneous substance.
COMPARATIVE EFFECTS OF THYROTROPHIN AND LONG-ACTING THYROID STIMULATOR ON IODIDE TRAPPING IN ISOLATED THYROID CELLS
Authors: Burke Gerald , Kowalski Kazimierz 
Published: December 2008

ABSTRACT
The effects of thyrotrophin (TSH) and long-acting thyroid stimulator (LATS) in isolated bovine thyroid cells were studied. Both TSH (1 to 100 mU/ml) and LATS-IgG (0.25 to 3.5 mg/ml; mouse bioassay response index = 500 %/mg) stimulated I− trapping in a dose-related manner with a maximum 58 ± 13 % increase and 62 ± 18 % increase over control 131I cell/medium (C/M) ratios, respectively. The stimulatory effects of TSH and LATS-IgG were similarly inhibited by Li+ ion, by membrane stabilizers (chlorpromazine, trifluoperazine) at concentrations > 1 × 10−5 m and by phentolamine, 10−6 to 10−4 m, but were unaffected by propranolol. When ineffective concentrations of either stimulator were combined with effective concentrations of the other, a significant reduction in stimulation of iodide trapping was consistently observed. Combinations of maximally effective concentrations of TSH and LATS had no additive effects on C/M ratio. Using equipotent (based on 4.5 h incubations) concentrations of TSH and LATS-IgG, TSH augmentation of I− trapping was apparent only after 60 min incubation, whereas LATS increased C/M ratios within 15 min.
These data provide further evidence that: 1) the thyroidal sites of action of TSH and LATS are similar or identical, and, 2) LATS is not slower in onset of action than TSH in vitro and with equipotent doses may be even faster.
STUDIES ON THE MOUSE UTERINE AUGMENTATION TEST FOR THE ASSAY OF FOLLICLE-STIMULATING HORMONE IN FOUR MOUSE COLONIES
Authors: Christie D. W. , Bell E. T. , Harrison D. 
Published: December 2008

ABSTRACT
Assays of follicle-stimulating hormone from the National Institutes of Health (NIH-FSH-S4) have been conducted using the uterine augmentation test in four strains of mice.
Dose response curves were determined for each strain using dosages of NIH-FSH ranging from 4–64 μg together with 0.1 IU human chorionic gonadotrophin (HCG) in five sc injections given over three days. The specificity of the assay was investigated in each strain by adding 2, 10 and 50 μg luteinizing hormone (NIH-LH-S6) to each of three doses of NIH-FSH, 6, 12 and 24 μg, forming a complete three factor experimental design; each mouse also received 0.1 IU HCG. Five mice from each strain were employed at each of the 64 treatment combinations.
Values for b and λ in the dose response studies were acceptable for quantitative work but all strains were relatively insensitive. In the specificity studies the analysis of variance showed that a marked strain variation existed in the magnitude of the response to NIH-FSH and to NIH-LH while one strain showed a significant interaction between these two hormones. Regression analysis was carried out and the influence of different doses of NIH-LH on the linear regression coefficient was examined. In general it was considered that, under the conditions employed, none of the four strains would prove useful in the uterine augmentation test.
THE CLINICAL USE OF CHLORPROPAMIDE IN DIABETES INSIPIDUS
Authors: Wales John K. , Fraser T. Russell 
Published: December 2008

ABSTRACT
Chlorpropamide has been shown to be an effective oral therapy in diabetes insipidus of hypothalamic-pituitary origin. In some cases with anterior pituitary dysfunction, although chlorpropamide was antidiuretic, hypoglycaemia was a barrier to continued therapy. Tests indicated that chlorpropamide does not produce this effect by a reduction in glomerular filtration rate nor by increasing vasopressin secretion, nor by acting like the thiazide diuretics in diabetes insipidus but is more likely to act by increasing the sensitivity of the renal tubule to low and otherwise ineffective concentrations of vasopressin.
STUDIES ON THE MECHANISM OF ACTION OF OESTROGENS ON THE PITUITARY-ADRENAL FUNCTION IN THE MALE RAT
Authors: Perklev Torsten 
Published: December 2008

ABSTRACT
A single injection of a long-acting oestrogen, polydiethylstilboestrol phosphate (PSP; 200 μg/100 g body weight), into adult male rats caused an enlargement of the adrenal glands and an approximate doubling of total adrenal 3β-hydroxysteroid dehydrogenase (3β-OHD) activity and plasma corticosterone concentration in animals sacrificed 11 to 14 days following injection.
The administration of interstitial cell stimulating hormone (ICSH) of human origin or a long-acting testosterone ester (Andradurin®) into the PSP-treated animals partially or completely counteracted the effects of the PSP treatment on adrenal weight and 3β-OHD activity. Daily injections of corticotrophin (ACTH) into intact male rats for 7 days caused a significant rise in the adrenal 3β-OHD activity. Gonadectomy of male rats resulted in increased adrenal weights and elevated adrenal 3β-OHD activity. The plasma corticosterone concentration was unaffected. PSP treatment significantly augmented the effects of the gonadectomy on the adrenal weight and 3β-OHD activity and caused an elevated plasma corticosteroid concentration. The adrenal enlargement following gonadectomy was completely reversed by testosterone replacement but was not influenced by daily injections of ICSH.
The data are interpreted as suggesting that the oestrogen-induced hyper-secretion of ACTH in the male rat may be mediated through an elevated activity of the corticosteroid-binding globulin, caused by a reduced plasma testosterone level and a stimulated thyroid activity.
CELLULAR VARIATION IN THE UPTAKE AND METABOLISM OF CORTISOL BY CANINE ERYTHROCYTES
Authors: Philip Elseworth L. I. , Marotta S. F. 
Published: December 2008

ABSTRACT
Samples of blood taken from 30 dogs were incubated with 1 μg cortisol/ml blood for 15 minutes. The RBC rapidly took up cortisol in varying amounts with the mean uptake being slightly greater than could be accounted for by equal distribution between plasma and RBC. The actual steroidal concentration associated with the RBC varied from 37.7 to 79.1 % in these 30 animals. It is suggested that some of the discrepancies in the literature relative to the quantitative association of cortisol with mammalian RBC may be related to the different kinds of RBC used to study uptake, as well as individual variation in cellular uptake. Also the finding of substantial quantities of cortisol associated with the RBC fractions of dog's blood suggests that no reliable estimates of blood steroidal concentration can be achieved without a knowledge of the quantity associated with the RBC. Cortisol reductase enzyme systems could not be detected in these cells. It is concluded that canine anucleated RBC do not possess the capacity to catabolize cortisol.
THE EFFECT OF TESTOSTERONE AND RELATED STEROIDS ON THE OXIDATIVE AND GLYCOLYTIC ACTIVITY AND ON LIPID SYNTHESIS OF TESTICULAR AND EJACULATED BULL SPERMATOZOA
Authors: Voglmayr J. K. 
Published: December 2008

ABSTRACT
The effect of testosterone and ten related steroids on the oxidative and glycolytic metabolism and on lipid synthesis of washed bull ejaculated spermatozoa in vitro have been studied and comparisons made with spermatozoa collected from the rete testis of the same animal. Testicular spermatozoa differed from ejaculated spermatozoa in their response to steroids. At a concentration of 100 μg/ml androstanedione and 5β-epiandrosterone depressed the oxidative metabolism of testicular spermatozoa, whereas androsterone and 5β-androsterone had the reverse effect; they stimulated rather than depressed the respiration and oxidation of glucose by these cells. By contrast, with the exception of androstenedione, dihydrotestosterone and 5β-androstanediol, the steroids always depressed the respiration of ejaculated spermatozoa. The effective steroids always enhanced glycolysis in both testicular and ejaculated spermatozoa. However, with the exception of androstanedione, the steroids which enhanced glycolysis of ejaculated spermatozoa were not the same which affected the glycolytic activity in testicular spermatozoa. Under anaerobic conditions, the steroids did not stimulate glycolysis of both types of spermatozoa to any extent. Testicular spermatozoa, incubated with no added steroid, incorporated more carbon from [U-14C] glucose into lipid than did ejaculated cells. The addition of steroids significantly increased or tended to increase lipid biosynthesis in both testicular and ejaculated spermatozoa. Androstanedione, 5β-androstanedione, 5β-androsterone and 5β-epiandrosterone were the most effective steroids in altering the metabolic pattern of the spermatozoa. The results indicate that the effect of steroid hormones depends on the »maturity« of the spermatozoa and also on the nature of the steroid.
BLOOD FLOW AND RADIOIODINE UPTAKE IN THE THYROID GLAND OF RATS AFTER ADMINISTRATION AND DISCONTINUATION OF CARBIMAZOLE AND PERCHLORATE
Authors: Kapitola J. , Schüllerová M. , Schreiberová O. 
Published: December 2008

ABSTRACT
The effect of carbimazole (0.02 % in the food for 7 days) and potassium perchlorate (1 % in the food for 7 days) on the blood flow (86Rb method) and radioiodine uptake in the thyroid gland of rats was studied. The administration of both drugs results in an increase in the thyroid blood flow (higher after carbimazole); after discontinuation, the thyroid blood flow in both cases returned to normal levels within 7 days. The radioiodine uptake after the discontinuation of carbimazole exhibits a marked rebound on the 1st and 2nd day, whereas after discontinuation of perchlorate it exceeds the normal level on the 4th–7th day. Thus, our present and previous studies reveal qualitatively the same changes in the thyroid blood flow after the administration and discontinuation of carbimazole, perchlorate and methylthiouracil, this in all probability being due to variations in the TSH level. The rebound phenomenon in the radioiodine uptake, demonstrable after both carbimazole and perchlorate, however, shows a different temporal characteristic.