bluuebunny/crossref_metadata_2025_split huggingface dataset:
DNA AND PROTEIN SYNTHESIS OF PROSTATIC CULTURES IN RELATION TO HISTOLOGICAL RESPONSE UNDER THE INFLUENCE OF TESTOSTERONE AND ITS METABOLITES
Authors: Johansson R. , Niemi M. 
Published: December 2008

ABSTRACT
Testosterone as well as dihydrotestosterone and 5α-androstane-3β,17β-diol were capable of maintaining, in rather low concentrations (0.02, 0.02 and 1.0 μg/ml, respectively), the histological structure of the rat ventral prostate in organotypic tissue culture. By means of histometrical analysis testosterone and dihydrotestosterone were found to be active in lower concentrations (0.05 μg/ml) than androstanediol. In addition to the visual evaluation of the structure of the explants their total DNA and protein content was measured as well as their rate of incorporation of tritiated thymidine and leucine. In a concentration of 1 μg/ml the response of the ventral prostate culture was almost equal to all the steroids. Androstanediol, however, caused no stimulation in lowest concentrations (0.02–0.1 μg/ml) and was not toxic in the highest concentrations (100 μg/ml) at which testosterone and dihydrotestosterone were definitely cytolytic. When the serum from the culture medium was omitted even hormone concentrations close to the physiological level (0.003 μg/ml) could stimulate thymidine and leucine incorporation into the cultured ventral prostate.
FURTHER STUDIES ON ENZYMIC INACTIVATION OF LUTEINIZING HORMONE – RELEASING HORMONE (LH-RH) BY PEPTIDASES IN THE RAT HYPOTHALAMUS
Authors: Griffiths E. C. , Hooper K. C. , Hopkinson C. R. N. 
Published: December 2008

ABSTRACT
Luteinizing hormone-releasing hormone (LH-RH) is known to be inactivated by peptidases in the rat hypothalamus with consequent loss of LH-releasing ability. To make a further study of the peptidases' action on the decapeptide, synthetic LH-RH and its [1–9NH2] analogue were incubated with the supernatant hypothalamic fraction containing the enzyme activity. Using an assay system measuring gonadotrophin release in ovariectomized/steroid-primed rats, both LH-RH and the [1–9NH2] analogue were found to be inactivated to different extents after incubation with the fraction, the analogue completely losing both LH- and FSH-releasing activity, and the releasing hormone almost completely losing its LH- and totally losing its FSH-releasing activity. The findings extend the initial studies by showing that the peptidases can remove both the decapeptide's intrinsic LH- and FSH-releasing activity and that these enzymes act on LH-RH at a site other than the C-terminal glycinamide, since they are able to inactivate the [1–9NH2] analogue lacking this residue.
INFLUENCE OF ACUTE ADMINISTRATION OF HUMAN GROWTH HORMONE AND ALPHA-MSH ON PLASMA CONCENTRATIONS OF ALDOSTERONE, CORTISOL, CORTICOSTERONE AND GROWTH HORMONE IN MAN
Authors: Birkhäuser M. , Gaillard R. , Riondel A. M. , Zahnd G. R. 
Published: December 2008

ABSTRACT
The effect of acute administration of human growth hormone (HGH) and of alpha-melanocyte stimulating hormone (alpha-MSH) on plasma aldosterone, cortisol, corticosterone and growth hormone has been studied in normal man and in patients with panhypopituitarism. There is no acute effect of exogenous HGH on plasma levels of aldosterone, cortisol and corticosterone in normal man and in patients with panhypopituitarism. The plasma level of immunoreactive HGH measured during acute HGH infusion in man does not seem to be proportional to the doses administered in our study. Alpha-MSH raises the concentration of plasma HGH, but this stimulation is not dose-dependent. Aldosterone, cortisol and corticosterone concentrations are not influenced by the elevation of HGH mediated by alpha-MSH in normal man. Although in some patients with panhypopituitarism an elevation of plasma aldosterone concentration following alpha-MSH infusion is observed, it is unlikely that MSH is directly involved in the acute regulation of aldosterone secretion in healthy subjects.
BIOLOGICAL ACTION OF THE LIPOTROPHIC PEPTIDES A AND B FROM PIG PITUITARY GLANDS
Authors: Weisweiler P. , Schwandt P. 
Published: December 2008

ABSTRACT
In vitro lipolysis was stimulated by porcine pituitary peptides A and B in the rabbit, rat, mouse, and guinea pig. The minimal effective doses were calculated from log dose response curves for free fatty acids and free glycerol liberation. The rabbit was most sensitive responding to 0.008 μg/ml (1.4 pm/ml) peptide A and 0.06 μg/ml (5.3 pm/ml) peptide B respectively. Minipig adipose tissue showed no reaction up to a peptide concentration of 100 μg/ml.
After intravenous injection of either peptide at the concentration of 50 μg/kg, FFA and free glycerol increased rapidly in the rabbit with maximal concentrations at 30 min, returning to near normal concentrations after 240 min. Blood glucose concentrations increased continuously in spite of hyperinsulinaemia with a peak concentration at 60 min and complete normalisation after 2 h.
Hypertriglyceridaemia and hypocalcaemia were observed in both lipotrophin and control groups. Furthermore, the saline injected rabbits also displayed a slight increase of glucose, FFA, and free glycerol plasma concentrations towards the end of the experiments, suggesting stress stimulated lipolysis. The insulinotrophic effect of both peptides was verified by the fact that injection of lipid emulsion plus heparin led to a comparable increase in FFA and glucose, but to no change in insulin concentrations.
THE ROLE OF REDUCED GLUTATHIONE IN THYROGLOBULIN PROTEOLYSIS IN VITRO
Authors: Pisarev M. A. , Dumont J. E. 
Published: December 2008

ABSTRACT
During the process of secretion of the thyroid hormones, stored thyroglobulin (Tg) is digested within the lysosomes. An acid protease has been found, but this enzyme hydrolyses Tg at a relatively slow rate and has a low pH optimum (3.6). Since previous work has shown a stimulatory effect of reduced glutathione (GSH) on Tg digestion the following studies have been performed.
Homogenates were obtained from dog thyroid and total homogenate or different subcellular fractions were used as enzyme source. Labelled thyroglobulin (125I) was purified from prelabelled dog thyroid and its hydrolysis, judged from the increase in butanol soluble radioactivity, was studied. The greatest stimulatory effect of GSH on Tg hydrolysis was found around pH 5.6. When butanol soluble radioactivity was considered as a function of incubation time and tissue concentration a linear relationship was found. GSH effect was evident at 2 mm. Subcellular distribution studies showed that the GSH-stimulated proteolytic activity was mainly found in the 15 000 × g pellet. Labelled Tg hydrolysis was progressively decreased with increasing amounts of non-labelled purified Tg. GSH also stimulated labelled insulin hydrolysis, but failed to alter haemoglobin or casein degradation. GSH could also be replaced by other reducing agents, like cysteine or dithiothreitol. The significance of these findings is discussed in relation to the process of thyroid hormone secretion.
SECRETION OF PROGESTERONE BY HUMAN OVARIES PERFUSED IN VITRO
Authors: Fukunishi H. , Mickan H. , Zander J. 
Published: December 2008

ABSTRACT
A system for the perfusion of isolated human ovaries is described. Krebs-Ringer bicarbonate buffer (pH 7.4) containing glucose, sodium lactate and pyruvate was perfused at a flow rate of 5–8 ml/min at 37°C through the ovarian artery. Oxygen uptake, LDH-activity, pH and progesterone secretion were determined as parameters of viability of the perfused organ. Our results demonstrate that a relatively simple system used for perfusion was able to preserve ovarian function for at least two hours. This experimental design should not be regarded as physiological but in addition to other experimental approaches it might provide information on the physiology of the human ovary. Though lower values of progesterone secretion than in vivo were found, a correlation of secretion and functional stage of the ovaries could be demonstrated.
EFFECTS OF THE LUTEINIZING HORMONE ON BLOOD FLOW IN THE FOLLICULAR RABBIT OVARY, AS MEASURED BY RADIOACTIVE MICROSPHERES
Authors: Janson Per Olof 
Published: December 2008

ABSTRACT
Previous reports on the ovarian hyperaemia induced by luteinizing hormone (LH) and human chorionic gonadotrophin (HCG) were based largely on direct observations and semi-quantitative methods. An accurate quantitation of ovarian blood flow changes would contribute to a better understanding of the mechanisms for and physiological significance of this rapid effect of the hormones.
In the present study ovarian blood flow was determined before and after a single intravenous injection of LH to anaesthetized, post-pubertal virgin rabbits, using 15 ± 5 μm microspheres, labelled with Ytterbium-169 and Scandium-46. Two min after administration of 100 μg of bovine LH a significant decrease in ovarian vascular resistance was noted. The response was even more pronounced after 20 min. Pre-treatment of the animals with an adrenergic β-receptor blocker did not diminish the LH induced ovarian vasodilatation. The vasodilatation appeared specific to the ovary, as indicated by simultaneous determinations of blood flow and vascular resistance in other organs and tissues.
The microsphere technique is considered to be the method of choice for future studies of the mechanism of the LH induced ovarian vasodilatation.
STUDIES ON 17β-HYDROXYSTEROID DEHYDROGENASE IN HUMAN ENDOMETRIUM AND ENDOMETRIAL CARCINOMA
Authors: Pollow K. , Lübbert H. , Jeske R. , Pollow B. 
Published: December 2008

ABSTRACT
Kinetic parameters, substrate specificity and stability of a cytoplasmic 17β-hydroxysteroid dehydrogenase of human secretory endometrium were studied. Using oestradiol as substrate, oestrone formation was found to be linear with time and the concentration of protein. The optimum temperature was 40°C and the optimum pH 9.5. For the reduction of oestrone the optimal pH was 6. With NADP the maximal velocity was about 1/3 of that with NAD (0.23 nmoles/mg protein/10 min). The Km for oestradiol was 3.3 × 10−6 m. Testosterone and androstenedione also served as substrates but they were interconverted more slowly than oestradiol and oestrone. Sulphhydryl groups were shown to be essential for catalysis. The enzyme is cold sensitive but cold inactivation can be reduced by NAD, NADP, oestradiol or glycerol.
ORGAN-SPECIFIC ONTOGENESES OF STEROID HORMONE METABOLIZING ENZYME ACTIVITIES IN THE RAT
Authors: Ghraf Rüdiger , Vetter Ulrich , Zandveld Jeane Marie , Schriefers Herbert 
Published: December 2008

ABSTRACT
The development and sexual differentiation of 11β- and 17β-hydroxysteroid dehydrogenase activities was investigated in the liver, kidney, adrenal and gonads of rats over a period of 15–120 days of life.
11β-Hydroxysteroid dehydrogenase in the adrenal and ovary was at the limit of detectibility at all the stages of life investigated. In the liver, kidney and testis the enzyme activity is restricted to the microsomal fraction and demonstrates an age-dependent development; in the liver, kidney and in the gonads it is additionally characterized by a sexual differentiation to higher values in the male sex.
In all the organs investigated the cytoplasmic and microsomal fractions contain 17β-hydroxysteroid dehydrogenase activity; the activities are very low in the microsomal fraction of the kidney and in the cytosol of the testis. In all the organs the enzyme activity of at least one cell fraction displays an age-dependent development. The only activities, not demonstrating an ontogenesis are those of the cytosol of the adrenal and those of the microsomal fraction of the kidney. The age-dependent development is accompanied by a sexual differentiation of the enzymes activities. The only exception is the microsomal activity of the liver. The female sex shows the higher activity in the kidney, adrenal and gonads; whereas the male animal shows the higher activity only in the cytosol of the liver.
The developmental processes of 11β- and 17β-hydroxysteroid dehydrogenase have the following properties in common:
In the immature phase (day 15–30) the activities of the enzymes develop either very rapidly to manifold higher values or remain constant at the low neonatal level; no sexual differentiation of the enzymes activities occurs at this stage of life. The rapid increase in activity is found only in the liver and kidney, that is in the steroid hormone catabolizing organs. It does not occur in the steroid hormone producing glands.
ACCUMULATION OF ALPRENOLOL IN SOME POLYPEPTIDE HORMONE PRODUCING CELLS AND IN MELANIN-CONTAINING TISSUES
Authors: Slanina Premysl , Tjälve Hans 
Published: December 2008

ABSTRACT
The distribution of the β-adrenergic-receptor blocking drug alprenolol labelled with 3H was studied in mice by whole body autoradiography. The most characteristic feature in the distribution pattern was the accumulation in endocrine cells within the pancreatic islets, the adrenal medulla, the pituitary gland and some cells of the thyroid, presumably representing the parafollicular cells. A high accumulation was also observed in melanin-containing tissues.
ORGAN CULTURE OF HUMAN SOMATOTROPHIC PITUITARY ADENOMAS: ULTRASTRUCTURE AND GROWTH HORMONE PRODUCTION
Authors: Peillon F. , Gourmelen M. , Donnadieu M. , Brandi A. , Sevaux D. , Pham Huu Trung M. T. 
Published: December 2008

ABSTRACT
Ten somatotrophic adenomas removed from acromegalic patients and fragments of the non-tumoural surrounding pituitary were submitted to organ culture for periods of up to one month.
Electron microscopic observation shows that these tumours retain their histological differentiation throughout the culture period. The cell morphology of the cultured tumours remains essentially unchanged and in particular the secretory granules keep their initial size (150 and 130 nm). However the granules disappear gradually so that most of the cells look chromophobic by the 4th week of culture, and numerous lysosomes as well as autophagic figures appear at the same time.
The hGH concentration in the culture medium has been measured of 4 adenomas. It is very high (10-fold greater than that from non-tumoural pituitary medium) during the first week (range 200–300 μg/ml).It still remains very high in the same experiments until the second week of culture in one experiment (200 μg/ml). After incubation of cultures with 3H-leucine, 3H-hGH is obtained in the medium giving evidence of hormone synthesis by adenoma cells in culture. 3H-hGH represents 40 % of 3H-proteins in the culture medium and gives the same elution pattern as standard hGH on Sephadex G 100 chromatography.
A certain degree of correlation is observed between morphological and biological results: the greatest hGH production is obtained from explants which maintain the best histological appearance.
INHIBITION OF PROLACTIN SECRETION BY LERGOTRILE MESYLATE: MECHANISM OF ACTION
Authors: Clemens James A. , Smalstig E. Barry , Shaar Carl J. 
Published: December 2008

ABSTRACT
Lergotrile mesylate (2-chloro-6-methylergoline-8β-acetonitrile, methanesulphate salt) was shown to be a potent inhibitor of prolactin secretion in vivo and in vitro. The dopamine receptor blocker, pimozide, was able to reverse the inhibitory effect of lergotrile mesylate (LM) on prolactin release from rat pituitaries in vitro. Alpha-adrenergic or beta-adrenergic receptor blockers were unable to antagonize the action of LM on prolactin release. These findings indicate that ergolines such as LM inhibit prolactin release from pituitaries by activating an adenohypophyseal dopamine receptor. LM is currently undergoing clinical trial as a prolactin inhibitor and a dopamine agonist.
ROLE OF GROWTH HORMONE IN THE ENHANCEMENT OF THE PROPYLTHIOURACIL-INDUCED GOITROGENESIS BY SMALL DOSES OF THYROXINE
Authors: Ching Melvin C. H. , Schalch Don S. , Lebda Nancy J. A. 
Published: December 2008

ABSTRACT
The potcntiation of the propylthiouracil (PTU)-induced goitrogenesis after chronic administration of small doses of thyroid hormone has been attributed to the high circulating level of thyrotrophin (TSH) or to the re-instatement of insulin. In re-examining this problem radioimmunoassayable concentrations of TSH, thyroxine (T4), insulin, and growth hormone (GH) were observed in sera of rats at sequential intervals after surgical or chemical thyroidectomy and after thyroidectomy and replacement therapy with GH or T4. In addition, TSH, GH or a combination of both hormones were injected into hypophysectomized recipients in a further attempt to delineate the effect of either hormone on the thyroid. As expected, the rate of body growth was inversely proportional to the apparent severity of the hypothyroidism achieved in the several experimental groups. Goitrogenesis was enhanced after T4 treatment but evidently was not the exclusive result of increased blood levels of TSH or insulin. Evidence is presented that suggest the enhancement of goitrogenesis may be a growth phenomenon involving the additive or synergistic action of GH and TSH and possibly of other hormones.
THE INFLUENCE OF ANDROGENS ON PROTEIN SYNTHESIS BY CULTURED RAT EPIDIDYMAL TUBULES
Authors: Blaquier Jorge A. 
Published: December 2008

ABSTRACT
Rat epididymal tubules maintained in organ culture for 3 days respond to the addition of androgens to the culture media (testosterone and dihydrotestosterone 1 × 10−5 m and 1 × 10−7 m) with an increased incorporation of amino acids into acid-insoluble material. Significant androgenic stimulation is observed only 24 h after addition of hormone, while an inhibitory effect is found at earlier periods. The stimulation seems to be specifically produced by androgens; it is blocked by cyproterone acetate and is not elicited by oestradiol-17β or corticosterone. The process appears to involve RNA synthesis since actinomycin D suppresses the stimulatory effect of androgen. Evidence suggests that cAMP production is not a primordial step in the response to androgen since dibutyryl cAMP did not mimick the androgenic effect, theophylline did not potentiate the response and α,β-methylene ATP, which competitively inhibits adenyl cyclase, failed to alter the androgenic effect. Radioactive testosterone and dihydrotestosterone added to the culture media showed a preferential intranuclear localization as well as extensive metabolism. DHT was found to be the principal intranuclear steroid.
GROWTH IN MONOLAYER CULTURE OF RAT PITUITARY CELLS WHICH SYNTHETIZE AND RELEASE ACTH
Authors: Lang R. E. , Hilwig I. , Voigt K. H. , Fehm H. L. , Pfeiffer E. F. 
Published: December 2008

ABSTRACT
Cultures of rat pituitary gland cells were developed to study biosynthesis and release of ACTH. ACTH measurement was accomplished by radioimmunoassay. ACTH release was observed following stimulation with theophylline and cAMP in a dose-dependent manner. Biosynthesis was demonstrated by incorporation of 3H-phenylalanine into the hormone, employing a double antibody technique.
ACUTE SUPPRESSIVE EFFECT OF HUMAN GROWTH HORMONE ON BASAL INSULIN SECRETION IN MAN
Authors: Adamson Ulf , Cerasi Erol 
Published: December 2008

ABSTRACT
The acute effects of human growth hormone (GH) on the basal levels of glucose and insulin in blood were investigated in 11 healthy men. GH doses of 5, 10, 20, and 40 μg/kg body weight were given iv as a constantrate infusion over 30 min, and resulted in peak hormone levels (30 min) of 20.5 ± 1.0, 48.5 ± 2.2, 108.2 ± 4.5, and 229.2 ± 14.6 ng/ml, respectively. There was a small (max 9.8 ± 2.6 %) but significant decrease in the blood glucose level, observed already at 15 min after the beginning of the GH infusion and persisting up to 90 min. The highest dose of GH induced the most marked changes, but there was otherwise no clear correlation between dose and effect. The basal plasma insulin levels showed a more marked (max 16.0 ± 4.7 %) decrease which was not correlated, in time or in magnitude, with the changes in blood glucose. In some subjects, in whom no significant decrease in blood glucose was observed, plasma insulin still demonstrated a similar fall (max 20.2 ± 7.6 %). Neither were these changes in plasma insulin correlated to the dose of GH within the range used in this study. The findings suggest that the early, insulin-like effect of GH on blood glucose is distinct from its effect on the pancreas. The latter is a suppressive one, consistent with earlier findings on glucose-induced insulin release.
THE CONCENTRATION OF PROSTAGLANDIN F2α IN MATERNAL PLASMA, FOETAL PLASMA AND AMNIOTIC FLUID DURING PREGNANCY IN WOMEN
Authors: Johnson D. A. , Manning P. A. , Hennam J. F. , Newton J. R. , Collins W. P. 
Published: December 2008

ABSTRACT
The concentration of prostaglandin F2α has been determined in serial samples of peripheral venous plasma from women at defined times during labour, and studied in detail throughout two consecutive uterine contractions. In addition, the same compound has been measured in single samples of uterine venous plasma, cord venous plasma, and amniotic fluid in groups of patients during early and late pregnancy, labour and at delivery of the baby.
The results from the analysis of peripheral venous plasma show that there is considerable individual variation in the concentration of prostaglandin F2α during labour (mean ± sd, 33.1 ± 11.6 pg/ml). However, it is not possible to establish a definite correlation with either the latent or accelerated phases or with the time of delivery. Furthermore, there is no apparent temporal relationship between the concentrations in peripheral venous plasma and the contractile state of the uterus as assessed by external tocography.
In early pregnancy (16th to 20th week) the concentration of prostaglandin F2α (pg/ml, mean ± sd) in peripheral venous plasma is 26.3 ± 4.3 and in amniotic fluid 32.7 ± 26.5. At the 36th week to the start of labour the corresponding values are 27.1 ± 8.1 and 110.0 ± 73.8. At the same time the levels in cord plasma and uterine venous plasma are 100.4 ± 74.9 and 87.9 ± 55.0 respectively. During labour there is a significant increase (P < 0.005, Student's t-test) in the concentration in amniotic fluid (335.1 ± 171.0).
The results are discussed in relation to the possible role of prostaglandin F2α in the process of parturition.
PARADOXICAL EFFECT OF SALMON CALCITONIN ON SERUM CALCIUM: STUDIES IN INTACT AND THYROPARATHYROIDECTOMIZED MEN AND DOGS
Authors: Mohamadi Mahmood , Becker Kenneth L. , Bivins Leonard E. 
Published: December 2008

ABSTRACT
Total serum calcium of normal men, a hypoparathyroid man, two thyroparathyroidectomized men, and intact and thyroparathyroidectomized dogs were studied at multiple intervals following the acute administration of synthetic salmon calcitonin.
Calcitonin produced marked fluctuations in serum calcium in one normal man and a biphasic hypocalcaemic response in another. In four of five intact dogs, calcitonin caused absolute or relative hypercalcaemia. In contrast, administration of calcitonin to thyroparathyroidectomized dogs caused a hypocalcaemia with less fluctuations and with no periods of hypercalcaemia.
It is possible that some of the paradoxical responses of serum calcium induced by exogenous calcitonin are due to overcompensation by parathyroid hormone. However, other mechanisms may be involved. Our findings indicate that when the disturbing influence is sufficiently great, the control of serum calcium is not as well modulated as previously suspected. In addition, our findings of paradoxically hypercalcaemic responses to calcitonin indicates that the pathophysiologic interpretation of serum calcium at any single moment in time following the administration of this hormone to either intact or thyroparathyroidectomized men or dogs is a precarious endeavour.