bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of hyperprolactinaemia on glucose tolerance and insulin release in male and female rats
Authors: Reis F M , Reis A M , Coimbra C C 
Published: December 2004

Abstract
It has been shown that prolactin (PRL) induces glucose intolerance, hyperinsulinaemia and insulin resistance in several animal species, including rats. However, the sex differences regarding glucose homeostasis and insulin release in hyperprolactinaemic subjects have not been assessed to date. In the present study, hyperprolactinaemic (pituitary-grafted) or control (sham-operated) male and female rats were submitted to an i.v. glucose tolerance test (30 mg/100 g body weight, 30% glucose). Grafted female rats had fasting plasma glucose concentrations 26% above control (P<0·01). After the glucose load there was a rapid and pronounced increase in plasma glucose levels in all animal groups, followed by a return to basal values within 30 min. However, the glucose concentrations in hyperprolactinaemic rats were significantly greater than those in controls at 5 min (males, P<0·05) and 30 min (females, P<0·05). The glucose disappearance rate was significantly increased in the grafted females compared with control (P<0·01) and slightly increased in the grafted males. Plasma insulin concentration increased just after glucose load and returned to basal values within 5 min in all groups except for the grafted females, which had recovered their basal insulin levels at 15 min. The grafted male rats had insulin concentrations higher than those of sham-operated controls at 2 min (28·9 ± 3·6 vs 17·3 ± 2·1 μU/ml, P<0·01), whereas females had plasma insulin concentrations greater than those in sham-operated controls 10 min after the glucose load (15·9 ± 1·9 vs 10·1 ± 1·4 μU/ml, P<0·05). The areas under the plasma insulin concentration–time curves were also significantly increased in the hyperprolactinaemic rats and were positively correlated with plasma PRL concentrations (r=0·613, P<0·01). These results demonstrate that moderate chronic hyperprolactinaemia is associated with increased glucose-induced insulin release, which was altered at different times after the glucose load in grafted male and female rats, whereas fasting hyperglycaemia was observed only in grafted females, indicating a sexual dimorphism in the diabetogenic effects of PRL in rats.
Journal of Endocrinology (1997) 153, 423–428
Involvement of bombesin in spermine-induced corticosterone secretion and intestinal maturation in suckling rats
Authors: Kaouass M , Deloyer P , Dandrifosse G 
Published: December 2004

Abstract
In this study we investigated whether brain-gut peptides are implicated in the activation of the hypophysial-adrenal axis (HAA) in suckling rats treated orally with spermine.
The first group of rats received i.p. injections of bombesin, vasoactive intestinal polypeptide (VIP), somatostatin or neurotensin, starting on day 11 of life, and killed on day 14. The small intestine was removed and analysed for its content of proteins, DNA, polyamines and for its specific activity (SA) of disaccharidases. The second group of rats received one of the hormones cited above and was killed 45 min after the treatment for determination of corticosterone plasma concentration. Rats of the third group were adrenalectomised then treated with bombesin as the first group. The fourth group of rats was orally treated with spermine and sacrificed 2, 3, 4, 6 and 8 h thereafter for analysis of plasma and intestinal concentrations of bombesin.
The i.p. injection of bombesin increased the sucrase and maltase SA in the whole small intestine, while it decreased the lactase SA in the distal part. Intestinal weight and length, contents of DNA, protein, spermidine and spermine, and corticosterone plasma levels were enhanced by bombesin treatment. Somatostatin, neurotensin and VIP were ineffective on all the parameters studied. Adrenalectomy, in bombesin-treated rats, decreased the sucrase and maltase SA in the whole intestine, and decreased the lactase SA in the proximal intestine. It had no effect on intestinal weight and length, and protein content. Oral administration of spermine had no effect on plasma concentration of bombesin, whereas it decreased the content of this peptide in the whole small intestine.
It is possible that bombesin may control intestinal development in suckling rats and be a link between the ingestion of spermine and the liberation of corticosterone by the adrenal glands.
Journal of Endocrinology (1997) 153, 429–436
Participation of JAK, STAT and unknown proteins in human placental lactogen-induced signaling: a unique signaling pathway different from prolactin and growth hormone
Authors: Takeda Takashi , Kurachi Hirohisa , Yamamoto Toshiya , Homma Hiroaki , Morishige Kenichirou , Miyake Akira , Murata Yuji 
Published: December 2004

Abstract
The signal transduction mechanism involved in human placental lactogen (hPL) was studied. We have identified that hPL rapidly stimulated the tyrosine phosphorylation of at least 7 proteins including Janus Kinases (JAK1 and JAK2) and a signal transducer and activator of transcription protein (Stat3). This is the first evidence that the JAK-STAT pathway is involved in the hPL signaling. Moreover, two unknown proteins which were different from STAT proteins (Stat1, 3 and 5) in sizes were predominantly tyrosine-phosphorylated. Because human growth hormone (hGH) activates Stat1, 3, 5 and human prolactin (hPRL) activates Stat5, these results show that hPL uses a unique signal transduction pathway which is different from hGH and hPRL.
Cerebellin and cerebellin mRNA in the human brain, adrenal glands and the tumour tissues of adrenal tumour, ganglioneuroblastoma and neuroblastoma
Authors: Satoh F , Takahashi K , Murakami O , Totsune K , Ohneda M , Mizuno Y , Sone M , Miura Y , Takase S , Hayashi Y , Sasano H , Mouri T 
Published: December 2004

Abstract
The expression of cerebellin and cerebellin mRNA was studied by radioimmunoassay and Northern blot analysis in the human brain, adrenal gland and the tumour tissues of adrenal tumour, ganglioneuroblastoma and neuroblastoma. Immunoreactive cerebellin was detected in every region of brain studied, with the highest concentrations found in the hemisphere of the cerebellum (424·2 ± 12·6 pmol/g wet weight, n=6, mean ± s.e.m.) and the vermis of the cerebellum (256·8 ± 30·5 pmol/g wet weight). Immuno-reactive cerebellin was also detected in the pituitary (8·2 ± 1·8 pmol/g wet weight), the spinal cord (3·3 ± 0·3 pmol/g wet weight) and the normal parts of adrenal glands (2·98 ± 0·37 pmol/g wet weight, n=9) and some tumour tissues, such as phaeochromocytomas, cortisol-producing adrenocortical adenomas, ganglioneuroblastomas and neuroblastomas. Northern blot analysis showed that cerebellin mRNA was highly expressed in the hemisphere and vermis of the cerebellum. Cerebellin mRNA was also expressed in other regions of the brain and the tumour tissues of phaeochromocytoma, cortisol-producing adrenocortical adenoma, ganglioneuroblastoma and neuroblastoma. Immunocytochemistry of the normal adrenal gland showed that immunoreactive cerebellin was localized in the adrenal medulla. The present study has shown the expression of cerebellin and cerebellin mRNA, not only in the cerebellum but also in other regions of the brain and some tumours, such as cortisol-producing adrenocortical adenoma, phaeochromocytoma and neuroblastoma. These findings suggest possible pathophysiological roles of cerebellin peptides, not only in the cerebellum, but also in the extra-cerebellar tissues.
Journal of Endocrinology (1997) 154, 27–34
Thyroid hormone, vitamin D and retinoid receptor expression and signalling in primary cultures of rat osteoblastic and immortalised osteosarcoma cells
Authors: Bland R , Sammons R L , Sheppard M C , Williams G R 
Published: December 2004

Abstract
3,5,3′-Tri-iodothyronine (T3), 1α,25(OH)2-vitamin D3 (D3) and retinoids activate related nuclear receptors which interact by heterodimerisation to regulate gene expression. Actions of each hormone are discrete and may be specified by changes in the relative concentrations of their receptors (T3R, vitamin D receptor (VDR), retinoic acid receptor (RAR), retinoid X receptor (RXR)). T3, D3 and retinoids are essential for skeletal development and maintenance and we have previously shown complex interactions amongst their signalling pathways in osteosarcoma cells. In these studies we demonstrate that similar T3R, VDR, RAR and RXR proteins are co-expressed in both osteoblast lineage cell primary cultures and osteosarcoma cells by Western blotting. We investigated whether hormone interactions in bone result from changes in receptor stoichiometry. Cells were treated with combinations of T3, D3, 9-cis retinoic acid (9-cis RA) and all-trans retinoic acid (RA) that are known from previous studies to produce complex cell specific responses. No alteration in expression of any receptor protein was seen in response to any hormone combination in three phenotypically distinct osteosarcoma cell lines. Thus, in contrast to studies of overexpressed receptors in vitro, changes in the physiological concentrations of endogenous T3R, VDR, RAR and RXR do not specify discrete hormone actions in osteoblastic cells. Other unidentified factors are likely to modulate hormone action in these bone cells.
Journal of Endocrinology (1997) 154, 63–74
Oestrogen and progesterone control basic fibroblast growth factor mRNA in the rat uterus
Authors: Rider V , Carlone D L , Foster R T 
Published: December 2004

Abstract
Cell proliferation and differentiation in the rodent uterus are probably controlled by the interaction of female sex steroids with polypeptide growth factors. Uterine basic fibroblast growth factor (bFGF) mRNA was measured by RNase protection during the time (days 2–4) of endometrial cell proliferation in the pregnant rat. bFGF transcripts were detected at each of the 3 days of pregnancy examined. To investigate the influence of oestrogen and progesterone on bFGF mRNA accumulation, ovariectomized rats were treated with oestradiol for 48 h followed by a single injection of oestradiol, progesterone, the two steroids co-injected or oil vehicle alone. Uterine RNA was collected 6 h after the last hormone injection. Steroid treatments increased steady-state uterine bFGF mRNA compared with vehicle control animals as measured by RNase protection. Northern blot analysis of c-fos and c-jun mRNAs from these same treatment groups revealed increased protooncogene expression in the uterus of hormone treated rats compared with the control animals. Temporal analysis of bFGF mRNA in ovariectomized rats at 1, 3 and 6 h after acute oestrogen and oestrogen-progesterone co-administration showed a dual pattern of transcript accumulation. Both hormone treatments increased bFGF mRNA within 1 h compared with vehicle injected rats. Co-administration of the two hormones, however, repressed bFGF mRNA accumulation relative to oestrogen at 3 and 6 h. Together, these studies provide evidence that bFGF control of uterine cell proliferation in pregnant rats can occur from newly synthesized bFGF. Moreover, the results suggest that progesterone is a potent stimulator of bFGF expression in the uterus.
Journal of Endocrinology (1997) 154, 75–84
High levels of fetal membrane activin βA and activin receptor IIB mRNAs and augmented concentration of amniotic fluid activin A in women in term or preterm labor
Authors: Petraglia F , Di Blasio A M , Florio P , Gallo R , Genazzani A R , Woodruff T K , Vale W 
Published: December 2004

Abstract
The aim of the present study was to evaluate whether spontaneous labor at term and pathological preterm labor are associated with changes in the expression of activin A and activin receptor mRNAs in fetal membranes. In addition, amniotic fluid activin A concentration in women delivering at term or undergoing preterm labor was also measured.
The expression of activin βA subunit and activin receptor type II and type IIB mRNAs was assessed by reverse transcriptase-PCR on specimens of amnion and chorion collected from patients delivering at term or undergoing preterm labor. Control specimens were collected from women delivered by elective cesarean section who had not experienced labor.
A specific two-site ELISA was used to measure activin A concentrations in the amniotic fluid. A cross-sectional study of amniotic fluid retrieved by amniocentesis from 109 pregnant women was carried out. Patients were classified into the following groups: (1) healthy controls at term but not in labor (n=25); (2) healthy controls at term in spontaneous labor (n=40); (3) healthy controls between 23 and 36 weeks of gestation (n=12); (4) patients in preterm labor responding to tocolytic treatment (n=19); (5) patients in preterm labor with subsequent delivery (n=13).
Activin βA subunit and activin receptor type IIB mRNA levels in both the chorion and amnion in women delivering at term or after preterm labor were significantly higher than in women delivering without undergoing labor (P<0·01). Expression of activin receptor type II mRNA in membranes did not differ among the three groups of women. Amniotic fluid activin A concentration in patients in labor was significantly higher than in those at term but not in labor (P<0·01). Patients in preterm labor had significantly higher amniotic fluid activin A concentrations than women at the same stage of gestation (P<0·01). The highest values were found in women undergoing preterm labor and subsequent delivery.
In conclusion, spontaneous labor and preterm labor are characterized by increased synthesis and release of activin A from amniotic and chorionic cells and by an augmented expression of activin type IIB receptor.
Journal of Endocrinology (1997) 154, 95–101
The expression of parathyroid hormone-related protein mRNA and immunoreactive protein in human amnion and choriodecidua is increased at term compared with preterm gestation
Authors: Curtis N E , Ho P W M , King R G , Farrugia W , Moses E K , Gillespie M T , Moseley J M , Rice G E , Wlodek M E 
Published: December 2004

Abstract
Parathyroid hormone-related protein (PTHrP) gene expression and/or immunoreactive protein have previously been identified in the uterus and intrauterine gestational tissues. The putative roles of PTHrP during pregnancy include vasodilatation, regulation of placental calcium transfer, uterine smooth muscle relaxation and normal fetal development. The aims of this study were 1) to determine the tissue-specific and temporal expression of PTHrP mRNA and immunoreactive protein in human gestational tissues collected at preterm and term; and 2) to determine the effect of labour on PTHrP expression by collecting these tissues from women undergoing elective caesarean section (before labour), intra-partum caesarean section during spontaneous-onset labour (during labour), and women with spontaneous labour and normal vaginal delivery (after labour). Total RNA and protein were extracted from placenta, amnion (over placenta and reflected) and choriodecidua for analysis by Northern blot (using a specific human PTHrP cDNA probe), and by N-terminal PTHrP RIA respectively. In amnion over placenta, reflected amnion and choriodecidua both PTHrP mRNA relative abundance and immunoreactive protein were significantly elevated at term compared with preterm (P<0·01). At term, both PTHrP and its mRNA were significantly greater in amnion than in placenta and choriodecidua (P<0·05). Also, both PTHrP and its mRNA were significantly elevated in amnion over placenta compared with reflected amnion (P<0·05). The expression of PTHrP and its mRNA did not change in association with term labour or rupture of the fetal membranes, therefore this study provides no evidence for a specific PTHrP role in the onset and/or maintenance of term labour. However, the significant up-regulation of PTHrP mRNA and protein in the fetal membranes at term compared with preterm suggests an important role in late human pregnancy.
Journal of Endocrinology (1997) 154, 103–112
Characterization of the AT1 angiotensin II receptor expressed in guinea pig liver
Authors: García-Sáinz J A , Martínez-Alfaro M , Romero-Avila M T , González-Espinosa C 
Published: December 2004

Abstract
In guinea pig hepatocytes angiotensin II induced phosphorylase a activation. This effect was mimicked by other angiotensins with the potency order: angiotensin II (EC50 ≈1 nm)>angiotensin III (EC50 ≈30 nm)>angiotensin I (EC50 ≈300 nm). The effect of 10 nm angiotensin II was blocked by the angiotensin II receptor AT1-selective antagonists irbesartan and losartan (Ki values of ≈1 nm and ≈10 nm for irbesartan and losartan respectively) but not by the AT2-selective antagonist PD123177.
Similar data were obtained when the production of [3H]IP3 from [3H]myo-inositol-labeled cells was studied. Angiotensin II induced a dose-dependent increase in [3H]IP3 production; the maximal effect (≈3-fold) was observed at a concentration of 10 μm. This effect of angiotensin II was completely blocked by the AT1-selective antagonists irbesartan and losartan, but only in a very limited fashion by PD123177. [125I][Sar1-Ile8]angiotensin II bound with high affinity (≈3·8 nm) to a moderately abundant number of sites (≈660 fmol/mg protein) in guinea pig liver membranes. Binding competition experiments indicate the following orders of potency for agonists: angiotensin II (≈1·5 nm)>angiotensin III (≈7 nm)>angiotensin I (≈176 nm), and for antagonists: irbesartan (≈0·5 nm)>losartan (≈36 nm)&gt;&gt; PD123177 (&gt;&gt; 10 000 nm).
The functional and binding data strongly indicate that the effects of angiotensin II were mediated through AT1 receptors. Expression of the mRNA for these receptors was confirmed by RT-PCR and hybridization of the reaction product with a radiolabeled rat AT1 receptor cDNA probe.
Journal of Endocrinology (1997) 154, 133–138
The role of protein kinase C in GH secretion induced by GH-releasing factor and GH-releasing peptides in cultured ovine somatotrophs
Authors: Wu D , Clarke I J , Chen C 
Published: December 2004

Abstract
The involvement of protein kinase C (PKC) in the action of GH-releasing factor (GRF) and synthetic GH-releasing peptides (GHRP-2 and GHRP-6) was investigated in ovine somatotrophs in primary culture. In partially purified sheep somatotrophs, GRF and GHRP-2 caused translocation of PKC activity from the cytosol to the cell membranes and caused GH release in a dose- and time-dependent manner. GHRP-6 did not cause PKC translocation. The PKC inhibitors, calphostin C, staurosporine and chelerythrine, partially reduced GH release in response to GRF and GHRP-2 at doses which selectively inhibit PKC activity. These inhibitors totally abolished GH release caused by phorbol 12-myristate 13-acetate (PMA). Down-regulation of PKC by the treatment of cells with phorbol 12,13-dibutyrate for 16 h caused a significant (P<0·001) reduction in total PKC activity and totally abolished PKC translocation in response to a challenge with GRF, GHRP-2 or PMA. In addition, down-regulation abolished GH release in response to GRF, GHRP-2 or GHRP-6. Treatment of cells with H89, a selective PKA inhibitor, totally blocked GH release caused by either GRF or GHRP-2 and partially reduced PMA-induced GH release. H89 had no effect on PKC translocation caused by GRF, GHRP-2 or PMA and did not affect GH release caused by GHRP-6. These data suggest that GHRP-2 and GRF activate PKC in addition to stimulating adenylyl cyclase activity. Although the cAMP–protein kinase A (PKA) pathway is the major signalling pathway employed by GRF and GHRP-2, the activation of PKC may potentiate signalling via the cAMP–PKA pathway in ovine GH secretion. Importantly, the effect of PMA in increasing the secretion of GH from ovine somatotrophs is effected, in part, by up-regulation of the cAMP–PKA pathway. We conclude that there is cross-talk between the PKC pathway and the cAMP–PKA pathway in ovine somatotrophs during the action of GRF or GHRP.
Journal of Endocrinology (1997) 154, 219–230
All trans-retinoic acid acts synergistically with hydroxytamoxifen and transforming-growth factor β to stimulate apoptosis in MCF-7 breast cancer cells
Authors: Danforth D N 
Published: December 2004

The anti-estrogen 4-hydroxytamoxifen (TAM) and vitamin A-related compounds, the retinoids, in combination act synergistically to inhibit growth of breast cancer cells in vitro and in vivo. To clarify the mechanism of this synergism, the effect of TAM and all trans-retinoic acid (AT) on proliferation of MCF-7 breast cancer cells was studied in vitro. TAM and AT acted synergistically to cause a time-dependent and dose-dependent inhibition of MCF-7 cell growth. In a temporally related manner, TAM+AT acted synergistically to downregulate Bcl-2 mRNA and Bcl-2 protein expression, and to stimulate apoptosis. TAM and AT each blocked cell cycle progression throughout 7 days of treatment but without any synergistic or additive effect on this process, indicating a selective synergism for apoptosis.
The negative growth factor-transforming growth factor β (TGFβ) is secreted by these cells and was studied as a potential mediator of the synergistic effects of TAM+AT on apoptosis. TAM+AT acted synergistically to induce a fivefold increase in TGFβ1 secretion over 72 h. TGFβ1 alone had no apoptotic effects on these cells; however, TGFβ1 in combination with AT acted synergistically to inhibit growth, to downregulate Bcl-2 mRNA and Bcl-2 protein expression, and to stimulate apoptosis of these cells in a manner comparable with that noted for TAM+AT. The synergism of both TAM+AT and TGFβ1+AT for apoptosis was suppressed by estradiol. Co-incubation of TAM+AT with anti-TGFβ antibody did not block down-regulation of Bcl-2 protein expression or stimulation of apoptosis. The synergistic effects of TAM+AT on apoptosis therefore occur independently of TGFβ, although TGFβ may interact with AT in a novel manner to provide another important anti-proliferative mechanism for breast cancer cells.
Method for the determination of primary, secondary, and tertiary amino groups in star‐shaped polyamide 12 with a poly(ethylene imine) core
Authors: Baumann F. E. , Haeger H. , Novikova O. , Oenbrink G. , Richter R. 
Published: December 2004

AbstractA star‐branched poly(ethylene imine)‐g‐polyamide 12 with a high concentration of primary amino end groups is an object of interest for future chemical modifications. In many cases, the concentration of primary amino groups, which are also the end groups of the polyamide 12 arms, and the concentrations of secondary and tertiary amino groups in a sample need to be known independently. Because of the difference in the reactivity of phthalic acid toward amino groups, its reaction with poly(ethylene imine)‐g‐polyamide 12 can be used for the analytical determination of these groups. With primary amino groups, phthalic acid forms phthalimido moieties, which are detectable by IR spectroscopy. The IR bands can be used for quantitative analysis with an appropriate calibration procedure. The concentration of primary amino groups can also be calculated as the difference between the concentration of all types of amino groups before the reaction with phthalic acid and the final concentration of amino and carboxylic groups after the reaction. The final concentration of the amino groups is equal to the concentration of unreacted tertiary amino groups after the reaction with phthalic acid anhydride. The difference between the final concentration of carboxylic groups and the initial concentration of carboxylic groups is equivalent to the concentration of secondary amino groups, which react with phthalic acid to form phthalamido acid moieties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 556–563, 2005