bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of Galanin‐Like Peptide Gene Expression By Pituitary Hormones and Their Downstream Targets
Authors: Cunnningham M. J. , Krasnow S. M. , Gevers E. F. , Chen P. , Thompson C. K. , Robinson I. C. A. F. , Smith M. S. , Clifton D. K. , Steiner R. A. 
Published: February 2004

AbstractGalanin‐like peptide (GALP) mRNA is expressed in neurones of the hypothalamic arcuate nucleus and within pituicytes in the neurohypophysis. Several neuropeptides that are expressed in the arcuate nucleus participate in the neuroendocrine regulation of pituitary hormone secretion. Our objective was to determine the extent to which GALP might be a target for regulation by pituitary hormones or their downstream targets in the rat. The expression of GALP mRNA in the arcuate nucleus was reduced by hypophysectomy as determined by in situ hybridization. However, this did not appear to be attributable to the loss of either gonadal or adrenal steroids because castrated, ovariectomized and adrenalectomized rats had GALP mRNA expression that was indistinguishable from their respective controls. Next, we investigated the effects of growth hormone deficiency on GALP mRNA expression by studying dwarf rats and found that GALP gene expression was not different between dwarf rats and controls. We found that thyroidectomy led to a significant reduction in GALP mRNA expression compared to intact controls, and thyroidectomized rats implanted with thyroxine pellets had GALP mRNA expression that was similar to intact controls. Thus, the reduction of GALP mRNA expression seen in hypophysectomized animals may reflect, in part, a selective loss of thyroid hormone. We also found that the expression of GALP mRNA was increased in the neurohypophysis of lactating rats compared to nonlactating rats, whereas GALP mRNA expression in the arcuate nucleus was unaffected by lactation. This suggests that the induction of GALP gene expression in pituicytes is physiologically associated with activation of oxytocin and vasopressin secretion during lactation.
Expression of the Arginine Vasopressin Gene in Response to Salt Loading in Oxytocin Gene Knockout Mice
Authors: Ozaki Y. , Nomura M. , Saito J. , Luedke C. E. , Muglia L. J. , Matsumoto T. , Ogawa S. , Ueta Y. , Pfaff D. W. 
Published: February 2004

AbstractAccumulating evidence suggests that both oxytocin and arginine vasopressin (AVP) are vital components in the regulation of body fluid balance. However, the physiological role of oxytocin and possible cooperative interactions between oxytocin and AVP in sodium balance remain obscure, even though recent studies using oxytocin knockout (OTKO) mice suggested that oxytocin may contribute to the regulation of salt appetite. In the present study, we examined the effects of salt loading (drinking 2% NaCl for 5 days) on the expression of the AVP gene in the paraventricular (PVN) and supraoptic nuclei (SON) of wild‐type, OTKO and heterozygous littermates using in situ hybridization histochemistry. In addition, the effects of salt loading on the expression of the oxytocin gene were also examined in wild‐type and heterozygous mice. Under the non salt‐loaded condition, the levels of AVP mRNA in the PVN and SON of OTKO mice were significantly decreased compared to those in wild‐type mice. Nevertheless, the up‐regulation of the expression of the AVP gene in response to salt loading was preserved in OTKO mice. The degree of the up‐regulation in OTKO mice tended to be greater compared to those in wild‐type mice, suggesting compensatory up‐regulation of the expression of the AVP gene in OTKO mice after salt loading. The basal levels of oxytocin mRNA in the PVN and SON of heterozygous mice were significantly lower than those in wild‐type mice. Salt loading caused an increase of oxytocin mRNA levels in the PVN and SON of both wild‐type and heterozygous mice. The ratios of increase of oxytocin mRNA levels were very similar between wild‐type and heterozygous mice, suggesting that the single remaining oxytocin gene in heterozygous mice responds normally to an osmotic cue. Finally, salt loading tended to increase the serum concentration of sodium regardless of genotype, and there were no genotype differences in both the control and salt‐loaded groups. These results suggest ways in which oxytocin may play a cooperative role together with AVP in the regulation of sodium balance.
Dual Excitatory and Inhibitory Effects of Stimulation of Intrinsic Innervation of the Anterior Pituitary on Adrenocorticotropic Hormone Release in the Rat
Authors: Gao L.‐Z. , Ju G. 
Published: February 2004

AbstractThe gland cells of the mammalian anterior pituitary are innervated by substantial amounts of nerve fibres, and there is evidence that the nerve fibres are functionally active. In the rat, the nerve fibres make typical excitatory synapses with corticotropes. The physiological significance of this synaptic relationship was investigated in the present study. The anterior pituitary of the rat was sliced and stimulated with electrical field in a chamber. The perfusate was continuously collected and immunoradioassayed for adrenocorticotropic hormone (ACTH). When the gland slices were stimulated at a high frequency of 10 Hz, there was a significant inhibition of ACTH secretion. Stimulation at a low frequency of 2 Hz resulted in a quick and transient excitation of ACTH release. The results indicate that stimulation of the nerve fibres in the anterior pituitary has dual excitatory and inhibitory effects on ACTH secretion.
Reduced Progesterone Metabolites Protect Rat Hippocampal Neurones From Kainic Acid Excitotoxicity In Vivo
Authors: Ciriza I. , Azcoitia I. , Garcia‐Segura L. M. 
Published: February 2004

AbstractThe ovarian hormone progesterone is neuroprotective in some animal models of neurodegeneration. Progesterone actions in the brain may partly be mediated by the locally produced metabolites 5α‐dihydroprogesterone and 3α,5α‐tetrahydroprogesterone. The neuroprotective effects of these two metabolites of progesterone were assessed in this study. Ovariectomized Wistar rats were injected with kainic acid, to induce excitotoxic neuronal death in the hippocampus, and with different doses of 5α‐dihydroprogesterone and 3α,5α‐tetrahydroprogesterone. The number of surviving neurones in the hilus of the dentate gyrus of the hippocampus was assessed with the optical disector method. The administration of kainic acid resulted in a significant decrease in the number of hilar neurones and in the induction of vimentin expression in reactive astrocytes, a sign of neural damage. Low doses of 5α‐dihydroprogesterone (0.25 and 0.5 mg/kg body weight, b.w.) prevented the loss of hilar neurones and the appearance of vimentin immunoreactivity in astrocytes. Higher doses (1–2 mg/kg b.w.) were not neuroprotective. By contrast, low doses of 3α,5α‐tetrahydroprogesterone (0.25–1 mg/kg b.w.) were unable to protect the hilus from kainic acid while higher doses (2–4 mg/kg b.w.) were protective. The different optimal neuroprotective doses of 5α‐dihydroprogesterone and 3α,5α‐tetrahydroprogesterone suggest that these two steroids may protect neurones using different mechanisms. The neuroprotective effects of 3α,5α‐tetrahydroprogesterone may be exerted by the inhibition of neuronal activity via the GABAA receptor. This latter possibility is supported by the observation that 3β,5α‐tetrahydroprogesterone, an isomer of 3α,5α‐tetrahydroprogesterone that does not bind to GABAA receptor, was not neuroprotective. In summary, our findings suggest that progesterone neuroprotective effects may be, at least in part, mediated by its reduced metabolites 5α‐dihydroprogesterone and 3α,5α‐tetrahydroprogesterone.
Altered Expression of p53 mRNA in the Brain and Pituitary During Repeated Immobilization Stress: Negative Correlation with Glucocorticoid Receptor mRNA Levels
Authors: Nishimura K. , Makino S. , Tanaka Y. , Kaneda T. , Hashimoto K. 
Published: February 2004

AbstractIn our previous study, apparent reduction of glucocorticoid receptor (GR) mRNA was seen in the hippocampus and the hypothalamic paraventricular nucleus (PVN) during repeated immobilization (IMO) stress, but not following starvation. Our laboratory has also shown that the sp1 activates, whereas tumour suppressor p53 represses the promoter activity of GR gene. In an attempt to reveal the possibility that transcription factors such as sp1 and/or p53 are involved in the regulation of GR mRNA expression in the hippocampus and in the PVN in vivo, we examined the expression of GR mRNA, p53 mRNA, and sp1 mRNA in the hippocampus and in the PVN during repeated IMO and following starvation. In addition, the expression of these mRNAs was examined in the anterior pituitary, another GR‐rich area. GR mRNA in all subfields of the hippocampus was robustly decreased, while GR mRNA in the anterior pituitary was increased, 24 h following 4 × IMO (2 h daily, for 4 consecutive days) and immediately after 5 × IMO. GR mRNA in the PVN was significantly decreased immediately after 5 × IMO, but not at 24 h after 4 × IMO. Conversely, p53 mRNA in the PVN and hippocampus was increased, whereas p53 mRNA in the anterior pituitary was decreased, 24 h following 4 × IMO and immediately after 5 × IMO. Sp1 mRNA was unchanged in all areas examined following repeated IMO. Following 4 days of starvation, neither GR mRNA, p53 mRNA nor sp1 mRNA showed any changes in the PVN and the hippocampus, except there was a minor decrease in GR mRNA in CA1‐2. In the anterior pituitary, 4 days of starvation induced a minor, but significant increase in GR mRNA, whereas it decreased p53 mRNA. Overall, regression analyses revealed a negative correlation between GR mRNA levels and p53 mRNA levels in CA1‐2 and dentate gyrus of the hippocampus and in the anterior pituitary. GR mRNA in the PVN also showed a tendency towards the negative correlation with p53 mRNA levels. The results raise the possibility that p53 negatively regulates GR mRNA expression in the PVN, the hippocampus and the anterior pituitary during repeated immobilization stress.
Circadian Rhythm of Melatonin Release From the Photoreceptive Pineal Organ of a Teleost, Ayu (Plecoglossus altivelis) in Flow‐Thorough Culture
Authors: Iigo M. , Fujimoto Y. , Gunji‐Suzuki M. , Yokosuka M. , Hara M. , Ohtani‐Kaneko R. , Tabata M. , Aida K. , Hirata K. 
Published: February 2004

AbstractIn the present study, we tested whether the pineal organ of ayu (Plecoglossus altivelis), an osmerid teleost close relative of salmonids, harbours a circadian oscillator regulating rhythmic melatonin release using flow‐through culture. The pineal organ maintained under light/dark cycles released melatonin in a rhythmic fashion with high levels during the dark phase. A circadian rhythm of melatonin release persisted in constant darkness for at least four cycles. Characteristics of the circadian rhythm (free‐running period, phase and amplitude) exhibited small variations among cultures when the data was normalized, indicating that this system is sufficient for the analysis of the circadian rhythm both at qualitative and quantitative levels. Six‐hour extension of the light phase from the normal onset time of the dark phase or exposure to constant light for 36 or 48 h before transfer to constant darkness significantly inhibited melatonin release. Phase shifts in the circadian rhythm of melatonin release were also observed. Thus, the ayu pineal organ contains all the three essential components of the circadian system (a circadian clock, the photoreceptor responsible for photic entrainment of the clock, and melatonin generating system as an output pathway). This system should provide a useful model for analysing the physiological and molecular basis of the vertebrate circadian system. In addition, further comparative studies using salmonids and related species including ayu will provide some insight into the evolution of the roles of the pineal organ in the vertebrate circadian system.
Effects of population spatial structure on the quantity and quality of seeds set byPrimula sieboldii(Primulaceae)
Authors: WATANABE ATSUKO , GOKA KOUICHI , WASHITANI IZUMI 
Published: February 2004

AbstractEffects of spatial population structure on the reproductive success ofPrimula sieboldiiE. Morren, an endangered heterostylous perennial, were studied through the analysis of quantity and quality of seeds in a natural habitat in central Japan. Seed set of individual flowering ramets varied significantly depending on the degrees of isolation from their potential mates. The flowering ramets, which have the opposite‐morph ramets within 5 m, set significantly higher mean seeds per flower (approx. 15) than that of more isolated ramets (approx. 5). The former produced a considerably variable number (0–100) of seeds per flower, while the latter set more or less uniform number of seeds per flower. Viability of seeds from the former ramets was also variable with significantly higher mean viability percentage than the latter. Early seedling survival was also significantly different between the maternal isolation classes, while survival and growth of the established seedlings in a greenhouse did not differ significantly between these classes. The level of allozyme heterozygosity of the surviving progenies was not significantly different between the classes differing in maternal isolation. The observation suggests that the isolated maternal plants produced fewer and less viable seeds, which may be a result of strong inbreeding depression that manifests in early life stages of the progenies. By the stage of seedling establishment, therefore, less fit homozygotes are purged while fitter heterozygotes are allowed to survive irrespective of maternal isolation.
Oxylobium/Gastrolobium(Fabaceae : Mirbelieae) conundrum: further studies using molecular data and a reappraisal of morphological characters
Authors: CHANDLER GREGORY T. , BAYER RANDALL J. , GILMORE SIMON R. 
Published: February 2004

AbstractA molecular phylogeny ofOxylobium,Gastrolobiumand related genera, includingBrachysema,Jansonia,NemciaandPodolobium,is presented. The study was conducted using five molecular regions and 48 taxa, utilizing chloroplast DNA (thetrnK 5′ intron,psbA/trnH intergenic spacer,trnL intron and adjacenttrnL/trnF intergenic spacer) and nuclear ribosomal DNA (ETS and ITS) markers.Oxylobiumis shown to be polyphyletic, whileGastrolobiumis paraphyletic, containing within it the generaBrachysema,JansoniaandNemcia, as well asOxylobium lineare. This concurs with a previous molecular analysis and the results of the two analyses are compared. Morphological traits, such as subtending bracts, ovule number and fluoroacetate content, are shown to be homoplastic and suites of characters for defining the different genera using different morphological characters are presented. Our results support a recent monograph that expandsGastrolobiumto includeBrachysema,Jansonia,NemciaandOxylobium lineare. This revision leavesOxylobiumandPodolobiumoccurring exclusively in eastern Australia, whileGastrolobiumoccurs almost exclusively in south‐western Australia, with only two species,G. brevipesandG. grandiflorum, occurring outside this area.
Effects of nutrient availability on the production of pentaynene, a secondary compound related to defense, in Rudbeckia hirta
Authors: ALMEIDA‐CORTEZ JARCILENE , SHIPLEY BILL , ARNASON JOHN THOR 
Published: February 2004

AbstractThis study focused on the effect of different availabilities of mineral resources in hydroponic culture on the production of polyacetylenic defences of Rudbeckia hirta L. Specifically, we investigated if there was any difference concerning the amount of pentaynene, measured with high performance liquid chromatography (HPLC), produced in flowers of plants grown at high light intensity (500 µmol m−2 s−1 photosynthetic photon flux density) and two levels of mineral resources (full strength and 1/5 dilution) in a hydroponic solution. A working hypothesis was that the concentration of secondary compounds would increase with decreasing nutrient supply, in accordance with the carbon:nutrient balance hypothesis. The amount of pentaynene produced in the flowers of R. hirta decreased with increasing flower age but increased significantly when the plant was subjected to a reduced nutrient availability. The decrease in pentaynene concentrations with flower age was also less pronounced in the nutrient‐stressed plants.
Unusual Crystallization Behavior of Selenium in the Presence of Organic Molecules at Room Temperature
Authors: Ohtani Tsukio , Takayama Norihiro , Ikeda Kazuaki , Araki Masako 
Published: February 2004

Abstract
Amorphous Se was converted into fibrous crystals of hexagonal Se or polyhedral crystals of α-monoclinic Se when exposed to organic fluids at room temperature for several days. The growth phase was dependent upon the dielectric constant of the organic liquids. It is notable that hexagonal Se and α-monoclinic Se formed under vapors of d- and l-camphor, respectively. It is proposed that the organic compounds do not act as solvents, but play a catalytic role in the reactions.
Chiral analysis of butaclamol enantiomers in human plasma by HPLC using a macrocyclic antibiotic (vancomycin) chiral stationary phase and solid phase extraction
Authors: Aboul‐Enein Hassan Y. , Hefnawy Mohamed M. 
Published: February 2004

AbstractAn enantioseparation of the antipsychotic drug butaclamol in human plasma by high‐performance liquid chromatography (HPLC) with solid phase extraction is presented. The separation was achieved on the vancomycin macrocyclic antibiotic chiral stationary phase (CSP) Chirobiotic V with a polar ionic mobile phase (PIM) consisting of methanol : glacial acetic acid : triethylamine (100:0.2:0.05, v/v/v) at a flow rate of 0.5 ml/min. The detection wavelength was 262 nm. Bond Elut C18 solid phase extraction cartridges were used in the sample preparation of butaclamol samples from plasma. The method was validated over the range of 100–3,000 ng/ml for each enantiomer concentration (R2 > 0.999). Recoveries for (+)‐ and (−)‐butaclamol were in the range of 94–104% at the 300–2,500 ng/ml level. The method proved to be precise (within‐run precision ranged from 1.1–2.6% and between‐run precision ranged from 1.9–3.2%) and accurate (within‐run accuracies ranged from 1.5–5.8% and between‐run accuracies ranged from 2.7–7.7%). The limit of quantitation (LOQ) and limit of detection (LOD) for each enantiomer in human plasma were 100 ng/ml and 50 ng/ml, respectively. Chirality 16:147–152, 2004. © 2004 Wiley‐Liss, Inc.
Enantiomeric separation of dansyl amino acids using macrocyclic antibiotics as chiral mobile phase additives by narrow‐bore high‐performance liquid chromatography
Authors: Sharp V. Scott , Letts Maureen N. , Risley Donald S. , Rose John P. 
Published: February 2004

AbstractSeven macrocyclic antibiotics were evaluated as chiral selectors for the enantiomeric separation of 11 dansyl amino acids using narrow‐bore high‐performance liquid chromatography (HPLC). The macrocyclic antibiotics were incorporated as mobile phase additives to determine the enantioselective effects on the chiral analytes. The resolution and capacity factor (k′) of each analyte were assessed while varying the structure of macrocyclic antibiotic and the mobile phase buffer pH. The selectivity of the chiral selectors was measured as a function of changes in these parameters. All 11 dansyl amino acids were separated by at least one of the chiral selectors. Three‐dimensional computer modeling of the more effective chiral selectors illustrated the importance of macrocyclic antibiotic structure concerning stereospecific analyte interaction. Chirality 16:153–161, 2004. © 2004 Wiley‐Liss, Inc.
Absorption, fluorescence, and cd spectroscopic study of chiral recognition by a binaphthyl‐derived chromogenic calixcrown host
Authors: Kubinyi Miklós , Pál Krisztina , Baranyai Péter , Grofcsik András , Bitter István , Grün Alajos 
Published: February 2004

AbstractThe (R)‐ and (S)‐enantiomers of a binaphthyl‐appended calix4crown‐6 ether with two 2,4‐dinitrophenylazo chromophore units ((R)‐1 and (S)‐1) as chiral hosts were tested in their reactions with the enantiomers of α‐methylbenzylamine ((R)‐MBA, (S)‐MBA)) and phenylglycinol ((R)‐PGL, (S)‐PGL) as chiral guests. The visible absorption spectra indicate a two‐step process: the first is a nonenantioselective proton transfer from the host to the guest, which is followed by the enantioselective real complexation. In the visible range of the CD spectra a positive/negative band belongs to the absorption of pure (R)‐1/(S)‐1, and a negative/positive exciton couplet to the absorption of (R)‐1‐(S)‐MBA/(S)‐1‐(R)‐MBA complexes. The latter phenomenon suggests that the complexation of amines is accompanied by a chiral arrangement of the two chromophore units in the hosts. The UV fluorescence of (R)‐1/(S)‐1 arising from the binaphthyl moiety is quenched by K+ ions, but not by the amine guests, showing that the interaction between the binaphthyl group and the complexed amines is weak. Chirality 16:174–179, 2004. © 2004 Wiley‐Liss, Inc.
Differential recognition of resveratrol isomers by the human estrogen receptor‐α: Molecular dynamics evidence for stereoselective ligand binding
Authors: Abou‐Zeid Laila A. , El‐Mowafy Abdalla M. 
Published: February 2004

AbstractResveratrol (RSVL) is a phytoestrogen that occurs naturally in two forms (trans‐ (E) and cis‐ (Z)). We have conducted molecular dynamics (MD) studies to differentially characterize the estrogen receptor‐α (ER‐α) binding profiles of RSVL stereoisomers. Favorable orientations for RSVL isomers at the ER‐α pocket were first inferred from (1) alignment with pharmacophoric elements of the pure ER‐α agonists estradiol (E2) and (2) assessment of ligand recognition by the ER‐α binding domain. Subsequently, these orientations for RSVL isomers were subjected to MD analyses versus E2. A 100‐picosecond MD simulation revealed that E2 contributed four stable hydrogen bonds with the key ER‐α pocket reasidue: Arg394, Glu353, His524, and Leu525. Further, E2 displayed favorable binding energy, conformational energy change (ΔE), and movement of the binding pocket residues (RMSd). Compared to E2, (E)‐RSVL lacked a hydrogen bond (HB) with His524 but formed three additional bonds with Gly521, Phe404, and Met343 of the ER‐α pocket. Further, (E)‐RSVL conferred more favorable energy of interaction, less favorable ΔE, but comparable RMSd values. In contrast, (Z)‐RSVL orientations missed hydrogen bonding (HB) with His524 and Leu525, two essential ligand binding residues, and/or produced considerably less favorable‐binding energy, −ΔE, and ‐RMSd values than did (E)‐RSVL. In conclusion, the present study demonstrates the utility of this MD model in distinguishing between RSVL stereoisomers. The weak binding of (Z)‐RSVL by the human ER‐α binding is congruent with its inferior ligand profiles in ER‐endowed biological systems. Further, evidence is provided for a considerable variation in the mode of recognition of the mixed agonist/antagonist (E)‐RSVL, and the pure agonist E2. Chirality 16:190–195, 2004. © 2004 Wiley‐Liss, Inc.