bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhancement of ectopic β-human chorionic gonadotrophin expression by interferon-α
Authors: Iles R. K. , Chard T. 
Published: December 2008

ABSTRACT
Treatment of three β-human chorionic gonadotrophin (β-hCG)-expressing bladder tumour cell lines with interferon-α (IFN-α) (5000 U/per 106 cells) enhanced the rate of β-hCG secretion from 34·2 ±0·9 to 102·5 ± 0·1 mIU/106 cells per 72 h in cell line 5637; 111·15 ± 11·75 to 261·8± 51·75 mIU/106 cells per 72 h in cell line RT112 and 503·25 ± 28·55 to 1361·65± 110·3 mIU/106 cells per 72 h in cell line SCaBER. IFN-γ had no effect on the rate of β-hCG secretion. Both interferons reduced the growth rate of the cells: incorporation of radiolabelled thymidine was reduced by 15–45% in the presence of IFN-α and by 20–53% with IFN-γ. Enhancement of β-hCG secretion by IFN-α was dose-dependent over the range 5–50 000 U/106 cells. Analysis of cell cycle profiles by flow cytometry showed no increase in the proportion of cells in the G0G1 phase in cultures treated with IFN-α.
The conceptus of some species produces substances which are either luteotrophic or anti-luteolytic. In sheep, the corpus luteum is maintained by ovine trophoblast protein-I, which has been shown to have structural homology with human IFN-α. In primates and a few other higher mammals, early pregnancy is maintained by chorionic gonadotrophin. IFN-α is also an early product of the human conceptus. We have now shown that IFN-α enhances the ectopic production of the β-subunit of hCG by bladder tumour cells. This study suggests a direct transcription/translational effect of this cytokine on the expression of a reproductive endocrine gene.
Journal of Endocrinology (1989) 123, 501–507
Activity of 17β-hydroxysteroid oxidoreductase in tissues of the human fetus
Authors: Milewich L. , MacDonald P. C. , Carr B. R. 
Published: December 2008

ABSTRACT
The interconversion of oestrone and oestradiol, androstenedione and testosterone, and dehydroepi-androsterone and 5-androstene-3β,17β-diol in mammalian tissues is catalysed by 17β-hydroxysteroid oxidoreductase (17β-HSOR). To identify tissue sites of 17β-HSOR activity in the human fetus, microsomal fractions from 15 different fetal tissues obtained from first and second trimester pregnancies were used for evaluation of enzymatic activity by use of [17α-3H] oestradiol as the substrate and NADP+ as the co-factor. With these reagents, the enzyme-catalysed reaction led to the production of both non-radiolabelled oestrone and NADP3H in equimolar amounts; the radioactivity associated with NADP3H was used to quantify 17β-HSOR activity. Activity of 17β-HSOR was present in microsomes of all the tissues evaluated. The specific activity of the enzyme was highest in liver and placental microsomes. The interconversion of oestradiol and oestrone in microsomal fractions of nine different fetal tissues was studied by the use of substrates labelled with tritium at stable nuclear positions ([6,7-3H]oestradiol and [6,7-3H]oestrone). The products, [3H]oestrone and [3H]oestradiol, were quantified by the use of established techniques; other metabolites formed in these incubations were not identified. The reductive pathway of metabolism (oestrone to oestradiol) appeared to be favoured in microsomal fractions prepared from placenta, fetal zone of the adrenal gland and, possibly, lung. The oxidative pathway (oestradiol to oestrone) appeared to be favoured in microsomes prepared from liver, intestine, stomach, kidney, brain and heart. 17β-HSOR activity in fetal liver also was assessed by the use of fresh and frozen-thawed tissue, homogenate, subcellular fractions, and, also, in primary hepatocytes maintained in culture; the specific activity of the enzyme was highest in the microsomal fraction of liver tissue and 17β-HSOR activity in liver microsomes was linear with time of incubation up to 1 h. In hepatocytes, the enzymatic activity was linear with time of incubation up to 2 h and with cell number up to 2·5 × 105 cells/ml; the apparent Michaelis constant of hepatocyte 17β-HSOR for oestradiol was 11 μmol/l. The specific activity of 17β-HSOR did not change after pretreatment of hepatocytes for 24 h with insulin, glucagon or dexamethasone.
Journal of Endocrinology (1989) 123, 509–518
UNCOUPLING OF RECEPTOR-MEDIATED CELLULAR RESPONSES BY IONIC LITHIUM
Authors: Zaidi M. , Patchell A. , Datta H.K. , MacIntyre I. 
Published: December 2008

ABSTRACT
The propensity of ionic lithium to interfere with the coupling of receptors to guanine nucleotide binding proteins (G-proteins) has only recently been investigated using rat cortical membranes. In the present study we have used intact isolated osteoclasts to investigate lithium-induced uncoupling of the receptor-mediated actions of calcitonin. All actions of calcitonin on the osteoclast were abolished by ionic lithium. We believe that the cation prevents signal transduction by inhibiting G protein-receptor interaction, the first step in intracellular signalling.
THE RESPONSE OF INHIBIN TO HUMAN CHORIONIC GONADOTROPHIN IS DECREASED IN SENESCENT MEN COMPARED WITH YOUNG MEN
Authors: Fingscheidt U. , Nieschlag E. 
Published: December 2008

ABSTRACT
Inhibin and testosterone were measured in the serum of young and old men with proven fertility before and after stimulation with human chorionic gonadotrophin (hCG) in order to characterize endocrinological changes in senescence further. While there was a significant increase of both hormones in all young men, there was a decreased response of serum testosterone and an insignificant increase in inhibin in the older men. Although basal hormone levels and ejaculate parameters were not different, hCG stimulation revealed that there were decreased secretory capacities of Leydig as well as of Sertoli cells in old age.
Occurrence of rare somatomammotrophs in ovine anterior pituitary tissue studied by immunogold labelling and electron microscopy
Authors: Thorpe J. R. , Ray K. P. , Wallis M. 
Published: December 2008

ABSTRACT
Prolactin and GH are distinct hormones that have been conventionally thought to be produced and secreted by separate cells in the anterior pituitary gland. Recently it has been suggested that some cells (somatomammotrophs) may secrete both hormones. We have examined the occurrence of somatomammotrophs in sheep anterior pituitary tissue using immunogold labelling. Of a number of procedures used, double labelling using first antibodies raised in different species proved the least susceptible to apparent co-localization of hormones due to artifacts. Using this approach it was shown that a large proportion of the cells in the sheep anterior pituitary glands examined were mammotrophs or somatotrophs, showing no significant co-localization of GH and prolactin. Of 1800 cells examined, only two were somatomammotrophs. One of these, from a female animal, contained GH and prolactin in different granules within the same cell. The other, from a male animal, showed co-localization of these two hormones within the same granules.
Journal of Endocrinology (1990) 124,67–73
Premature birth of live lambs induced by pulsatile infusion of ACTH
Authors: MacIsaac R. J. , Carson R. S. , Horvath A. P. , Wintour E. M. 
Published: December 2008

ABSTRACT
This study was designed to investigate the effects of pulsatile infusion of ACTH into ovine fetuses on the endocrine changes that precede parturition, the timing of birth and the subsequent survival of the lamb. Where appropriate, these parameters were compared with fetuses infused with pulses of saline and uninfused normal term fetuses. Ten fetuses received a 15-min infusion of synthetic ACTH(1–24) (79 ng/min) from day 125 (n=9) or day 126 (n=1) of gestation. Seven fetuses were born prematurely within 174±14 h (mean ± s.e.m.) after the commencement of the infusion, i.e. at 132 ± 0·6 days, whilst three died in utero at 130–131 days. When born all lambs could breath, walk and suckle. Of the seven premature lambs, four died 2–10 days after parturition but three survived for at least 12 months after birth. Fetuses infused with pulses of ACTH exhibited intermittent but very large increases in plasma ACTH values, with the first pulse, on day 1, increasing ACTH values from 5·1 ± 1·1 to 140 ± 31·3 pmol/l (P<0·001). At the next sampling time, ACTH values were not significantly different from preinfusion values. A similar plasma ACTH profile was observed on each subsequent day of ACTH treatment. In contrast, fetuses (n=4) infused with pulses of saline between 125 and 131 days exhibited fetal plasma concentrations of ACTH which ranged between 2 and 12 pmol/l for the majority of the time. Of the uninfused fetuses (n=8) that were studied during the last week of normal gestation, seven were born alive at 148·9± 1·0 days of gestation, whilst one lamb was stillborn at 146 days. In these fetuses, plasma concentrations of ACTH increased slowly to 35·6 ±2·4 pmol/l on the day before delivery with a further increase to 76·4± 3·9 pmol/l occurring on the day of delivery. In fetuses infused with pulses of ACTH there was also a significant (P< 0·001) increase in the fetal cortisol to corticosterone ratio from a value of 2·9 before the commencement of the infusion to 69·1 just before birth. In ewes bearing uninfused fetuses born at normal term, maternal plasma concentrations of progesterone on day 4 before delivery were significantly (P<0·05) lower than on day 5 before delivery. In comparison, in ewes bearing fetuses infused with pulses of ACTH, a significant (P<0·05) decrease from maternal plasma concentrations of progesterone on day 5 before delivery did not occur until day 1 before delivery. In ewes bearing uninfused or prematurely delivered fetuses infused with pulses of ACTH, maternal plasma concentrations of oestrogen did not significantly (P<0·01) increase until the day of parturition. It is concluded that a minimum of 6–7 days of ACTH treatment is required by the fetal adrenal for the induction of cortisol synthesis sufficient to produce the birth of viable lambs. However, premature lambs have a 57% mortality rate in the 2- to 10-day period after birth.
Journal of Endocrinology (1990) 124, 99–107
Effects of epidermal growth factor on gastrointestinal electromyographic activity of conscious sheep
Authors: McLeay L. M. , Comeskey M. A. , Waters M. J. 
Published: December 2008

ABSTRACT
Adult sheep were infused with depilating doses of epidermal growth factor (EGF) at 4 pg/kg per h for 24 h. Food was available ad libitum during recording of integrated electromyographic (EMG) activity of the gastrointestinal tract. In comparison with control sheep infused with saline, EGF reduced the frequency of A and B sequences of contraction of the reticulum and rumen over the 24-h period, an effect attributable to the consumption of less food. During the 24-h infusion, EGF stimulated phase III migrating myoelectric complex (MMC)-like activity of the duodenum with an associated decline in the EMG of the abomasal antrum.
Infusion of EGF for 1 h at 2·5 and 5·0 μg/kg per h in fasted animals produced inhibitory effects on the frequency of A sequences of contraction of the reticulum and rumen during the infusion, and on the amplitude of the ruminal EMG during, and in the hour following, infusion. Phase III MMC-like activity of the duodenum was stimulated by EGF in fasted animals.
It is concluded that in fed sheep, depilating doses of EGF have inhibitory effects on the EMG activity of the reticulum and rumen through reductions in food consumption and by other undefined mechanisms. Additional effects of EGF on the gastrointestinal tract of sheep include stimulation of duodenal phase III MMC-like activity.
Journal of Endocrinology (1990) 124, 109–115
Effect of high-density lipoprotein on bovine granulosa cells: progesterone production in newly isolated cells and during cell culture
Authors: O'Shaughnessy P. J. , Pearce S. , Mannan M. A. 
Published: December 2008

ABSTRACT
It has been proposed that changes in steroidogenesis which occur during early development of the corpus luteum may be due to increased availability of lipoproteins. Bovine follicular fluid, however, contains significant amounts of high-density lipoprotein (HDL), and granulosa cells are exposed to this lipoprotein before ovulation. To determine whether bovine granulosa cells can utilize HDL the effects of this lipoprotein on freshly isolated, non-luteinized granulosa cells and on granulosa cells undergoing luteinization in serum-free culture were examined. Cells were isolated from non-atretic, antral follicles and cultured for 12 h in 10% (v/v) lipoprotein-deficient serum to allow cell attachment. After this time cells were cultured in serum-free medium. During culture the cells underwent functional luteinization as assessed by an increase in basal progesterone output (9·6-fold in 7 days) which was associated with a marked increase in activity of cholesterol side-chain cleavage and loss of aromatase activity. Dibutyryl cyclic AMP (dbcAMP) increased basal production of progesterone about twofold but HDL alone had no effect. Addition of HDL plus dbcAMP, in contrast, caused a very marked stimulation (up to ten times) of basal steroidogenesis. This trophic effect of HDL and dbcAMP lasted at least 2 weeks. Activity of cholesterol side-chain cleavage was stimulated (threefold over basal) by dbcAMP during culture but HDL was without effect, alone or with dbcAMP.
Addition of HDL (in the presence or absence of dbcAMP) to freshly isolated granulosa cells had no significant stimulatory effect on progesterone production over 12 h in six experiments, and in two of these experiments a significant inhibitory effect was seen. Incubation with 22R-hydroxycholesterol, in contrast, caused a marked stimulation of progesterone production, indicating that the steroidogenic capacity of the cells was not already saturated. Results presented here suggest that bovine granulosa cells are able to utilize HDL for steroidogenesis only after luteinization. The massive secretion of progesterone by luteinized granulosa cells which occurs in the presence of HDL suggests that this lipoprotein is very important in the development and maintenance of luteal cell function in cattle.
Journal of Endocrinology (1990) 124, 255–260
Effect of ovariectomy and treatment with ovarian steroids on vasopressin release and fluid balance in the rat
Authors: Peysner K. , Forsling M. L. 
Published: December 2008

ABSTRACT
Plasma vasopressin concentrations have previously been shown to vary during the oestrous cycle of the rat, being highest on the morning of pro-oestrus and lowest on dioestrus day 1. To determine the effect of gonadal steroids on vasopressin secretion and fluid balance, mature rats were ovariectomized and given oestrogen, progesterone or vehicle alone s.c. for periods of up to 16 days. Plasma vasopressin concentrations fell after ovariectomy and this was reflected in an increase in 24-h urine volume. The normal increase in plasma vasopressin concentrations seen over daylight hours was also suppressed. The change in vasopressin concentrations observed on steroid treatment depended upon both the dose and the duration. High doses of oestrogen were associated with a fall in plasma vasopressin, probably as a result of fluid retention. Thus, of an initial group of rats given silicone elastomer implants containing 50, 500 or 1000 μg oestradiol in oil, plasma vasopressin concentrations were reduced after 7 days treatment with 1000 μg oestradiol implants in association with reduced plasma sodium concentrations. Daily s.c. injections of 100 μg oestradiol benzoate/100 g body weight produced an immediate small increase in plasma vasopressin concentrations, but by 14 days the plasma concentrations of 0·7 ± 0·16 pmol/l (mean ± s.e.m.) had fallen significantly and were less than those in the vehicle-treated group (1·2± 0·26 pmol/l). However, after treatment for 14 days with implants containing only 50 μg oestradiol, plasma vasopressin concentations were higher compared with the group receiving vehicle alone, despite the fact that the plasma osmolality was lower in the latter group, suggesting a long term resetting of the osmoreceptors. Progesterone treatment with two implants containing 17·5 mg progesterone in oil was associated with an initial suppression of plasma vasopressin concentrations, but 16 days after the implant the plasma concentrations were higher than in the control group. Neither oestrogen nor progesterone restored the vasopressin concentrations to those seen in the intact animal. Oestrogen treatment resulted in a reduction in food and water intake, whereas progesterone treatment produced an initial increase in food and water intake, and a fall in plasma osmolality which could account for the reduced plasma vasopressin. This was followed by an increase in urine flow over days 6 to 15. Thus ovariectomy had a marked effect on circulating vasopressin concentrations, probably as a result of complex changes since administration of either oestrogen or progesterone in doses giving normal circulating concentrations had little effect.
Journal of Endocrinology (1990) 124, 277–284
Effect of maternal hypothyroxinaemia in the rat on brain biochemistry in adult progeny
Authors: Hadjzadeh M. , Sinha A. K. , Pickard M. R. , Ekins R. P. 
Published: December 2008

ABSTRACT
The effects of maternal hypothyroxinaemia during pregnancy on subsequent brain biochemistry in progeny was studied. Normal and partially thyroidectomized rat dams were mated and progeny allowed to grow to adulthood. Brain regions (cerebellum, medulla, midbrain, cerebral cortex and paleocortex) were dissected out and the activities of various cell marker enzymes were determined, along with cholesterol contents.
Maternal hypothyroxinaemia was without effect on body weight, brain weight or thyroid status of adult progeny. Oligodendroglial marker enzyme activities were altered in progeny from thyroidectomized dams. 2′,3′-Cyclic nucleotide 3′-phosphohydrolase was decreased in the medulla (by 37%) and midbrain (by 32%). 5′-Nucleotidase was also diminished in the same brain regions, by 33% in the medulla and by 35% in the midbrain. In contrast, oleate esterase was increased (by 39%) in the paleocortex. Although these enzymes are putatively involved in myelin metabolism, no changes were observed in the concentration of a major myelin lipid (cholesterol). The activity of β-d-glucuronidase (a general neuronal marker) was decreased (by 30%) in the paleocortex, whereas N-acetyl-β-d-galactosaminidase (a general glial marker) was unchanged in all brain regions.
In summary, maternal hypothyroxinaemia has irreversible effects on brain biochemistry in adult progeny. The damage is parameter-selective and brain region-specific, analogous to the pattern of neurological damage seen in offspring born to hypothyroxinaemic women in iodine-deficient endemias.
Journal of Endocrinology (1990) 124, 387–396
Induction of lactogenic receptors in liver of hypophysectomized rats treated with bovine growth hormone–monoclonal antibody complexes
Authors: Thomas H. M. , Green I. C. , Wallis M. , Aston R. 
Published: December 2008

ABSTRACT
Male hypophysectomized rats treated with bovine (b)GH–monoclonal antibody complexes showed enhanced weight gain compared with animals treated with bGH alone over a 12-day treatment period. Liver microsomes prepared from animals showing enhanced weight gain exhibited increased specific binding of human (h)GH. Studies on the specificity of these binding sites showed that they were lactogenic, 125I-labelled hGH being displaced by ovine prolactin, but not by non-mammalian growth hormones. In this respect they were similar to lactogenic binding sites in the liver of pregnant rats. Monoclonal antibodies to hGH blocked binding to lactogenic receptors to different extents. The pattern of such inhibition was similar, but not identical, for the receptors induced in hypophysectomized rats and those from pregnant rat liver. The evidence available suggests that the lactogenic receptors induced by bGH–monoclonal antibody complexes are not directly involved in the enhancement of growth.
Journal of Endocrinology (1990) 124, 469–474
Evidence for steroid control of a putative angiogenic factor in the porcine uterus
Authors: Ashworth C. J. , Fliss M. F. V. , Bazer F. W. 
Published: December 2008

ABSTRACT
The formation of new capillaries, both in extraembryonic membranes and in the maternal endometrium, is an essential prerequisite for appropriate feto-maternal relationships throughout pregnancy. At present there is no indication of the nature of the uterine angiogenic stimulus. In-vitro, degradation products of hyaluronic acid, following its catalysis by hyaluronidase, have been shown to have angiogenic properties. In the current study, levels of hyaluronic acid in endometrial tissues and of hyaluronidase and hyaluronic acid in uterine flushings were measured during the oestrous cycle and early pregnancy.
The concentration of both hyaluronic acid and hyaluronidase in uterine flushings followed the growth and regression of the corpus luteum, in that basal levels detected on days 0 and 6 increased to peak concentrations on days 12 and 15. By day 18, levels of both hyaluronidase and hyaluronic acid had decreased in cyclic gilts, but remained increased in pregnant pigs. Tissue concentrations of hyaluronic acid were not affected by pregnancy or by the day of the oestrous cycle. In a subsequent experiment, four groups of gilts were ovariectomized on day 4 and thereafter received daily injections of corn oil, progesterone, oestrogen or a combination of oestrogen and progesterone. Hyaluronidase was undetectable in uterine flushings collected on day 15 from corn oil-and oestrogen-treated gilts, but present in similar amounts in uterine flushings from gilts treated with progesterone and progesterone plus oestrogen. Similarly, uterine fluid concentrations of hyaluronic acid were increased in progesterone- and progesterone plus oestrogen-treated gilts, but not in corn oil-or oestrogen-treated pigs. Tissue concentrations of hyaluronic acid were unaffected by steroid treatment.
These results indicate that progesterone stimulates secretion of hyaluronidase and hyaluronic acid; both substances believed to be associated with the presence of an angiogenic factor in the pig uterus, but there was no evidence of a synergistic interaction between progesterone and oestrogen.
Journal of Endocrinology (1990) 125, 15–19
Comparison of ACTH and ACTH precursor peptides secreted by human pituitary and lung tumour cells in vitro
Authors: Crosby S. R. , Stewart M. F. , Farrell W. E. , Gibson S. , White A. 
Published: December 2008

ABSTRACT
The molecular forms of ACTH secreted by established human small cell lung cancer (SCLC) cells and primary cultures derived from a bronchial carcinoid tumour, a pituitary adenoma and hyperplastic pituitary tissue have been characterized by Sephadex G-75 chromatography and quantified with two novel immunoradiometric assays for ACTH and ACTH precursor peptides. Pro-opiomelanocortin (POMC; Mr 31 000) and pro-ACTH (Mr 22 000) were secreted by all cell types. No smaller peptides were identified in the culture media from SCLC and bronchial carcinoid cells, implying a deficiency in the enzymes and/or intracellular organelles required for extensive POMC processing. A more heterogeneous profile of ACTH-containing peptides was produced by cells of pituitary origin, indicating more extensive proteolytic processing of POMC. However, the major peptide secreted by cells from a large aggressive pituitary adenoma was unprocessed POMC (Mr 31 000). These results suggest that both lung and pituitary cells in vitro retain their in-vivo pattern of POMC processing and provide valuable models in which to study the regulation of ACTH synthesis and secretion.
Journal of Endocrinology (1990) 125, 147–152