bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of an abundant α-class glutathione S-transferase in bovine and human adrenal cortex tissues
Authors: Meikle I. , Hayes J. D. , Walker S. W. 
Published: December 2008

ABSTRACT
Bovine adrenal cortex tissue expresses high levels of glutathione S-transferase (GST) from each of the α, μ and π gene families. We describe the purification and characterization of an abundant α-class GST from this tissue that has not been identified previously because of its failure to bind to S-hexylglutathione–Sepharose 6B (S-hexG-Ag). This enzyme has been affinity purified on glutathione–Sepharose 6B (GSH-Ag) and was obtained in a highly purified form by employing S-hexG-Ag to remove the bulk of GST before chromatography on GSH-Ag. The purified GST eluted from GSH-Ag was found to exhibit marked peroxidase and Δ5-ketosteroid isomerase activities (19·2 and 1·67 U/mg respectively). The bovine enzyme also showed high GST activity towards 4-hydroxynonenal (5·09 U/mg). Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed that the bovine GST contains two distinct polypeptides, one with an Mr of 25 900 and the other with an Mr of 26 500.
An abundant α-class GST was also purified from human adrenal cortex that possessed properties which were similar to the bovine α-class GST described above; however, unlike the bovine enzyme, the corresponding human α-class GST bound to S-hexG-Ag. As with the bovine enzyme, the purified human GST displayed marked peroxidase and isomerase activities (27 and 4·02 U/mg respectively). Further analysis on SDS-PAGE (Mr 25 800) and reverse-phase highperformance liquid chromatography established that this abundant α-class GST in human adrenal cortex is equivalent to the human liver GST B1B1 enzyme.
As both human and bovine adrenal cortex contain high levels of α-class GST with similar catalytic properties, we discuss the possible functions of these enzymes in this tissue.
Journal of Endocrinology (1992) 132, 83–92
Pituitary adenylate cyclase-activating polypeptide releases 7B2, adrenocorticotrophin, growth hormone and prolactin from the mouse and rat clonal pituitary cell lines AtT-20 and GH3
Authors: Propato-Mussafiri R. , Kanse S. M. , Ghatei M. A. , Bloom S. R. 
Published: December 2008

ABSTRACT
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide originally isolated from ovine hypothalami and so called because of its ability to stimulate pituitary adenylate cyclase activity. Alternative amidation and proteolytic processing of prepro-PACAP gives rise to two bioactive-amidated forms, PACAP-NH2(1–38) (PACAP-38) and PACAP-NH2(1–27) (PACAP-27). 7B2 is a polypeptide of 185 amino acids which is predominantly found in secretory granules and is widely distributed in rat and human tissues. We investigated the ability of the two forms of PACAP to stimulate GH, prolactin and 7B2 release by the rat pituitary clonal cell line GH3, and ACTH and 7B2 by the mouse pituitary clonal cell line AtT-20. PACAP-38 and PACAP-27 stimulated 7B2 and GH/prolactin or ACTH secretion with a similar efficacy over the 2-h incubation period from GH3 and AtT-20 cells respectively. 7B2 secretion was also stimulated by corticotrophin-releasing factor (CRF-41) and vasoactive intestinal polypeptide (VIP) in AtT-20 cells, and thyrotrophin-releasing hormone (TRH) and VIP in GH3 cells. Addition of PACAP to CRF-41 resulted in an additive effect on ACTH secretion and a synergistic effect on 7B2 secretion in AtT-20 cells. No synergism was observed when PACAP was added together with TRH, either on GH and prolactin secretion or on 7B2 release from GH3 cells. PACAP-mediated 7B2 secretion from both cell lines and PACAP-stimulated ACTH release from AtT-20 cells were reduced by 5 mg octapeptide synthetic somatostatin analogue/l (5 mg SMS 201-995/1).
Journal of Endocrinology (1992) 132, 107–113
A biphasic effect of noradrenaline on renin release from rat juxtaglomerular cells in vitro is mediated by α1- and β-adrenoceptors
Authors: Takagi M. , Atarashi K. , Matsuoka H. , Sugimoto T. 
Published: December 2008

ABSTRACT
The direct effect of noradrenaline on renin release from juxtaglomerular (JG) cells in vitro were investigated in a dynamic superfusion system of dispersed rat renal cortical cells. At low concentrations (1–100 nmol/l), noradrenaline stimulated renin release in a dose-dependent manner, while at higher concentrations (0·1–1 mmol/l) it inhibited renin release. The stimulatory effect of 0·1 μmol noradrenaline/l was completely blocked by a β-adrenoceptor antagonist, propranolol (0·1 μmol/l). When applied at concentrations of 1 μmol/l or 10 μmol/l, noradrenaline had no consistent effect on renin release, although 10 μmol noradrenaline/l had an inhibitory effect in the presence of propranolol (0·1 μmol/l). The inhibitory effect of noradrenaline (0·1 mmol/l) was converted to a stimulatory effect by the addition of an α1-adrenoceptor antagonist (bunazosin, 1 μmol/l), but was not altered by the addition of an α2-adrenoceptor antagonist (yohimbine, 1 μmol/l). These results indicate that low concentrations of noradrenaline directly stimulate renin release from JG cells by the activation of β-adrenoceptors, while high concentrations of nor-adrenaline inhibit renin release by the activation of α1-adrenoceptors. Accordingly, a dynamic balance may exist between β-adrenergic stimulation and α1-adrenergic depression of renin release.
Journal of Endocrinology (1992) 132, 133–140
Effect of dietary protein intake and intravenous glucose infusion on plasma concentrations of insulin-like growth factor-I in lambs
Authors: Kriel G. V. , Bryant M. J. , Lomax M. A. 
Published: December 2008

ABSTRACT
Two separate experiments were carried out to examine the effect of dietary protein intake on basal and GHstimulated plasma insulin-like growth factor-I (IGF-I) concentrations during either saline or glucose infusion into the jugular vein. In experiment 1, six castrated male lambs (27·1 ± 1·2 kg live weight (LW)) were fed a diet restricted in both metabolizable energy (ME; 0·18 MJ/kg LW per day) and nitrogen (2·0 g/kg LW per day) intakes, while in experiment 2 a further six lambs were fed a similar restricted ME intake but an increased nitrogen intake (3·0 g/kg LW per day). In both experiments glucose (experiment 1, 0·009 mmol/kg LW per min; experiment 2, 0·015 mmol/kg LW per min) or saline (0·25 ml/min) was infused for 6 days and plasma samples were obtained from the jugular vein at hourly intervals on day 4 (basal) or on days 5 and 6 after an i.v. GH challenge. In experiment 1 there was no increase in plasma IGF-I concentrations in response to the GH challenge during saline infusion, but during glucose infusion the plasma concentration of IGF-I increased to a peak after 24 h and declined over the next 20 h. Basal concentrations of IGF-I, insulin and glucose were significantly higher during glucose infusion. In experiment 2 the area under the IGF-I peak in response to the GH challenge was the same for the infusions of saline and glucose but the peak value for IGF-I was significantly higher during glucose infusion due to higher concentrations in the basal period. It is concluded that feeding a dietary intake of metabolisable energy and nitrogen which is only just sufficient to meet the requirements for maintenance of body tissues completely abolishes the increase in plasma IGF-I in response to GH challenge. Increasing the nitrogen supply in the diet or i.v. infusion of glucose re-establishes the IGF-I response to GH challenge as well as increasing basal IGF-I concentrations. The potential involvement of circulating concentrations of insulin, glucose and amino acids in the control of plasma IGF-I levels are discussed.
Journal of Endocrinology (1992) 132, 195–199
Hormone production in vivo and in vitro from follicles at different stages of the oestrous cycle in the sheep
Authors: Mann G. E. , McNeilly A. S. , Baird D. T. 
Published: December 2008

ABSTRACT
This experiment was undertaken in order to investigate the production of inhibin, oestradiol and androstenedione by ovarian follicles at different stages of the oestrous cycle in sheep. Twenty-four Scottish Blackface ewes were allocated to four groups of six ewes, i.e. those operated on during the luteal phase (day 10), and those operated on during the follicular phase 24–30, 36 and 60 h after the induction of luteal regression by an injection of 125 μg cloprostenol on day 10 of the luteal phase. Samples of jugular and ovarian venous blood were collected under anaesthesia and ovaries were then removed and all follicles larger than 3 mm diameter dissected out and incubated in medium for 2 h.
After injection of cloprostenol, luteal regression occurred as indicated by a fall in the secretion rate of progesterone. The ovarian secretion rate of inhibin was similar at all stages of the follicular phase and during the luteal phase while, in contrast, the secretion rate of oestradiol was significantly (P < 0·05) elevated in the group 24 h after injection of cloprostenol. There was good correlation between the in-vivo ovarian secretion rate and production rate during incubation in vitro for both inhibin (r = 0·57) and oestradiol (r = 0·60). When follicle diameter was compared with in-vitro hormone production there was good correlation for inhibin (r = 0·72) with larger follicles producing more inhibin, while the value for oestradiol was somewhat lower (r = 0·57) owing to the presence of large atretic follicles with low oestradiol production. Androstenedione production showed a lower correlation with follicle diameter (r = 0·39). When the four time periods were compared separately, there were significantly (P < 0·05) more follicles with high in-vitro oestradiol production (> 90 fmol/min) in the group at 36 h than in the other three groups, while inhibin release in relation to follicle size was similar in the four groups. Large oestrogenic follicles were responsible for 90% of the total oestradiol production during culture while only providing 55% of the total inhibin production, with large non-oestrogenic and small follicles contributing 33% and 12% of inhibin production respectively.
From the results of this study we conclude that while oestradiol is mainly produced by the large oestrogenic follicles, a considerable amount of inhibin is also produced by large non-oestrogenic and small follicles. We also found that a lack of variation in inhibin secretion rate in the intact animal was paralleled by a lack of variation in the pattern of inhibin produced from individual follicles.
Journal of Endocrinology (1992) 132, 225–234
The role of sex steroids in the formation of sex-differentiated concentrations of corticosteroid-binding globulin in rats
Authors: Mataradze G. D. , Kurabekova R. M. , Rozen V. B. 
Published: December 2008

ABSTRACT
The role of sex steroids in the programming of the level of serum corticosteroid-binding globulin (CBG) in the rat has been studied at different stages of ontogenesis.
The CBG content in the serum of mature female rats was 2·5 times higher than that in male rats. Sexual dimorphism of CBG content was absent in immature animals of 3–4 weeks of age. Castration of mature rats led to a 40–50% increase in CBG content. The CBG concentration in mature females or castrated adult males treated with testosterone propionate (TP; 3 mg/day for 4 days) was decreased by 40–50% compared with vehicle-treated rats. Oestradiol injection (1 μg/day for 4 days) had no influence on CBG levels in mature male and ovariectomized adult female rats.
Immature rats were castrated on days 1, 7, 14, 21, 28 or 35 of age and the CBG level was determined at 10–12 weeks of age. The CBG content of rats castrated up to day 28 of age was 2·5 times higher than that in mature males and did not differ from that in mature females. The CBG content of male rats castrated on day 35 of age was the same as that of adult castrated males. The CBG level in castrated rats treated with TP (1·25 mg for days 1–3 or 300 μg/day for 5 days after castration at day 7 up to day 26) did not differ from that in controls (i.e. vehicle-treated rats). TP injection into castrated rats on days 29–33 of age (300 μg/day) led to a 40–50% decrease in CBG level when compared with controls.
Ovariectomy of rats at different ages (on days 1 or 28 or 3 months) did not affect CBG concentration. TP injection (300 μg/day) into ovariectomized rats on days 29–33 had the same effect on CBG concentration as in males.
Gonadectomized rats treated with diethylstilboestrol on days 29–33 (100 μg/day) had the same CBG concentrations as TP-treated rats.
It was concluded that there is a short period during ontogenesis, from days 29 to 35 of age, which is critical for irreversible masculinization of the CBG concentration in male rats.
Journal of Endocrinology (1992) 132, 235–240
Acute effects of oestradiol and progesterone on melittin- and gonadotrophin-releasing hormone-induced LH secretion
Authors: Ortmann O. , Johannsen K. , Knuppen R. , Emons G. 
Published: December 2008

ABSTRACT
It is well established that oestradiol and progesterone modulate gonadotrophin-releasing hormone (GnRH)-induced LH secretion from cultured rat pituitary cells. Short-term oestradiol and long-term progesterone treatment exert inhibition, while short-term progesterone and long-term oestradiol treatment lead to enhancement of GnRH-stimulated LH secretion. There are several lines of evidence to suggest that the steroid effects might be mediated via a mechanism involving modulation of the GnRH signal-transduction system. To evaluate the role of arachidonic acid, which serves as an intracellular signal transducer by itself or its lipoxygenase metabolites, in the mediation of oestradiol and progesterone actions, we examined their effects on melittin (activator of phospholipase A2)-stimulated LH secretion. When pituitary cells from adult female rats were treated for 48 h with 1 nmol oestradiol/l or 1 nmol oestradiol/l plus 100 nmol progesterone/l, GnRH (1 nmol/l)-induced LH secretion was stimulated or inhibited respectively. However, melittin (10–300 nmol/l)-stimulated LH secretion remained unaffected after such treatment. Short-term treatment with oestradiol inhibited GnRH-induced LH secretion while progesterone treatment of oestradiol-primed cells led to a stimulatory effect. Interestingly, melittin-stimulated LH secretion was influenced in the same way after the short treatment paradigm. Perifusion studies were performed to assess the kinetics of these acute steroid actions further. Four separate perifusion chambers were continuously perifused with medium and stimulated for 2 min with 1 nmol GnRH/l or 1 μmol melittin/l every 50 min in a pulsatile fashion. When 1 nmol oestradiol/l was added to the perifusion medium after the application of an initial control pulse, GnRH- and melittin-stimulated LH secretion were inhibited by 69 and 61% respectively. This effect was present after 50 min. When oestradiol-primed cells were treated with 100 nmol progesterone/l starting after the initial GnRH or melittin pulse, an acute stimulatory effect was observed in response to both stimuli after 50 min. LH release was enhanced by up to 279 (GnRH) or 419% (melittin) compared with the control pulse. The kinetics of inhibited or stimulated pulsatile LH secretion were virtually identical when GnRH or melittin were used as stimuli. These results demonstrate that short-term oestradiol or progesterone treatment modulate arachidonic acid-mediated LH secretion in a similar fashion to GnRH-induced LH secretion, while long-term oestradiol or progesterone treatment only affected GnRH-induced LH secretion.
Journal of Endocrinology (1992) 132, 251–259
Characterization of chicken lung angiotensin I-converting enzyme
Authors: Polanco M. J. , Miguel J. L. , Agapito M. T. , Recio J. M. 
Published: December 2008

ABSTRACT
Angiotensin I(AI)-converting enzyme (ACE) (EC 3.4.15.1) was solubilized from the membrane fraction of chicken lung using trypsin and nonidet P40 extraction, and then purified to homogeneity by captopril affinity chromatography. Comparison of trypsin-extracted and detergent-solubilized membrane-bound converting enzyme by sodium dodecyl sulphatepolyacrylamide gel electrophoresis and isoelectric focusing indicated that the membrane-binding sequence contributed to a large extent to the size and charge of the enzyme. Both forms of the enzyme were glycoproteins but they differed in the glucidic content; 4·5% by weight of the enzyme in the trypsin-extracted ACE and 15% by weight of the enzyme in the detergent-solubilized ACE. In both cases hexoses were the most abundant residues. Both forms of the enzyme were found to contain 1 g-atom zinc/mol enzyme.
The purified enzymes did not only split Hip-His-Leu but also AI and bradykinin. The Michaelis constant (Km) and maximum velocity (Vmax) values of the trypsin-extracted ACE for Hip-His-Leu were 52 × 10−5 mol/l and 15·36 nmol/min respectively, and for AI they were 7·8 × 10−5 mol/l and 0·45 nmol/min respectively. The Km and Vmax values of the detergent-solubilized ACE for Hip-His-Leu were 32 × 10−5 mol/l and 11·75 nmol/min respectively, and for AI they were 6·5 × 10−5 mol/l and 0·97 nmol/min. Both forms of the enzyme required the same chloride ion concentration (0·3 mol/l) for the optimum enzyme activity and showed the same pH optimum (8·5) with Hip-His-Leu as substrate. Both were inhibited by EDTA in a similar manner. In addition, they were inhibited by the peptides AII and His-Leu, but captopril was the most potent inhibitor with inhibition constant values of 1·6 nmol/l and 2·0 nmol/l for the trypsin-extracted and the detergent-solubilized ACE respectively.
Journal of Endocrinology (1992) 132, 261–268
Effect of increased production of growth hormone on body composition in mice: transgenic versus control
Authors: Searle T. W. , Murray J. D. , Baker P. J. 
Published: December 2008

ABSTRACT
The body composition (water, fat, protein and ash) of male and female transgenic mice which had a sheep metallothionein 1a–sheep growth hormone fusion gene and their non-transgenic controls was determined at intervals from birth to 21 days of age (weaning) in 66 mice of each group, and in an additional 64 mice over the period 25 to 98 days of age. Overall 520 mice were analysed. Weaned mice were starved over-night prior to slaughter. Food was available ad libitum. and, after weaning, a zinc sulphate supplement was added to the drinking water to initiate expression of the transgene.
Growth and body composition were similar in all groups before weaning. From 39 days of age, transgenic females became progressively heavier than corresponding controls, being 60% heavier at the end of the experiment. They contained less fat, more water and slightly less ash than did controls of the same live weight but similar amounts of protein. When examined on a fat-free basis, they had less protein and ash and more water than corresponding controls. Appropriate linear and quadratic regression equations are presented to describe the above relationships.
Growth and body composition were more variable in transgenic males but, on average, similar to controls.
Journal of Endocrinology (1992) 132, 285–291
Growth hormone stimulates granulation tissue formation and insulin-like growth factor-I gene expression in wound chambers in the rat
Authors: Steenfos H. H. , Jansson J.-O. 
Published: December 2008

ABSTRACT
It has been reported that GH stimulates fibroblast growth and wound healing. In the present study we measured the effect of locally applied GH on insulin-like growth factor (IGF-I) mRNA concentrations and granulation tissue formation in wound cylinders, implanted s.c.
Four stainless-steel wiremesh cylinders were implanted s.c. in the back of male rats (280 g). Each cylinder was then injected every day with either 0·014 or 0·14 U human GH, or vehicle only. Ingrown granulation tissue and wound fluid was obtained on day 17 after implantation. The wet weight of granulation tissue was determined and concentrations of IGF-I mRNA in the tissue were measured by solution hybridization/RNAase protection assay. Similar assays were used to measure the levels of IGF-I receptor mRNA and GH receptor mRNA, while the IGF-I concentration in wound fluid and serum was determined by radioimmunoassay (RIA) after acid–ethanol extraction.
The concentrations of IGF-I mRNA in ingrown granulation tissue as well as the wet weight of this tissue were significantly higher in the GH-treated cylinders. There was no significant effect of GH on IGF-I receptor mRNA and GH receptor mRNA levels. Consistent with the results of previous studies, wound fluid IGF-I levels were lower than serum IGF-I levels, but no significant difference was found between the GH-treated cylinders and the control cylinders.
The results of the present study show that GH stimulates granulation tissue formation and increases the concentration of IGF-I mRNA in the ingrown granulation tissue.
Journal of Endocrinology (1992) 132, 293–298
Effect of fusidic acid on interleukin-1 (IL-1)- and IL-6-induced pancreatic β-cell functions in rats
Authors: Bendtzen K. , Diamant M. , Horn T. , Pedersen C. , Buschard K. 
Published: December 2008

ABSTRACT
Fusidic acid and its sodium salt (fusidin) are antistaphylococcal drugs with a steroidal primary structure. Both compounds have been shown to prevent the lymphocyte co-stimulatory activities of the cytokines, interleukin (IL)-1 and IL-6, in a manner similar to that of cyclosporin A. As shown in this paper, fusidin also prevents the inhibitory effect of human recombinant IL-1β (rIL-1β) and the stimulatory effect of human rIL-6, on glucose-induced insulin production in vitro by normal rat pancreatic islets. The drug also inhibited rIL-1β-induced IL-6 production by the islets. Fusidin showed a dose-related effect at pharmacologically relevant concentrations from 3 to 30 μg/ml, and the drug was progressively less active when added 1, 4 and 24 h after rIL-1β. Electron microscopical studies showed that β cells cultured for 72 h with rIL-1β accumulated less lipid in the presence of fusidin, most probably reflecting the functionally protective effect of the drug. Other characteristic ultrastructural changes induced in β cells by rIL-1β were, however, not altered. It is suggested that fusidin may prove clinically effective as a modulator of IL-1- and IL-6-induced changes in β-cell functions.
Journal of Endocrinology (1992) 132, 345–352