bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of nitric oxide synthase III in human thyroid follicular cells: evidence for increased expression in hyperthyroidism
Authors: Colin Ides M , Kopp Peter , Zbären Jakob , Häberli André , Grizzle William E , Jameson J Larry 
Published: December 2008

Abstract
Nitric oxide mediates a wide array of cellular functions in many tissues. It is generated by three known isoforms of nitric oxide synthases (NOS). Recently, the endothelial isoform, NOSIII, was shown to be abundantly expressed in the rat thyroid gland and its expression increased in goitrous glands.
In this study, we analyzed whether NOSIII is expressed in human thyroid tissue and whether levels of expression vary in different states of thyroid gland function. Semiquantitative RT-PCR was used to assess variations in NOSIII gene expression in seven patients with Graves' disease, one with a TSH-receptor germline mutation and six hypothyroid patients (Hashimoto's thyroiditis). Protein expression and subcellular localization were determined by immunohistochemistry (two normal thyroids, five multinodular goiters, ten hyperthyroid patients and two hypothyroid patients).
NOSIII mRNA was detected in all samples: the levels were significantly higher in tissues from hyperthyroid patients compared with euthyroid and hypothyroid patients. NOSIII immunoreactivity was detected in vascular endothelial cells, but was also found in thyroid follicular cells. In patients with Graves' disease, the immunostaining was diffusely enhanced in all follicular cells. A more intense signal was observed in toxic adenomas and in samples obtained from a patient with severe hyperthyroidism due to an activating mutation in the TSH receptor. In multinodular goiters, large follicles displayed a weak signal whereas small proliferative follicles showed intense immunoreactivity near the apical plasma membrane. In hypothyroid patients, NOSIII immunoreactivity was barely detectable.
In summary, NOSIII is expressed both in endothelial cells and thyroid follicular cells. The endothelial localization of NOSIII is consistent with a role for nitric oxide in the vascular control of the thyroid. NOSIII expression in thyroid follicular cells and the variations in its immunoreactivity suggest a possible role for nitric oxide in thyrocyte function and/or growth.
European Journal of Endocrinology 136 649–655
Effects of Benthic Prey Composition and Abundance on Diet and Growth of Black Crappies in Three Florida Lakes
Authors: Tuten Travis , Allen Micheal , Cichra Chuck 
Published: December 2008

AbstractThe influence of benthic prey availability on growth of black crappies Pomoxis nigromaculatus is poorly understood due to scant research on the relationships between benthic prey abundance and composition and black crappie diet. However, benthic taxa play an important role as prey items of black crappies during intermediate ontogenetic diet phases. We evaluated diet, growth, and abundance of black crappies in three large Florida lakes (Lochloosa, Marian, and Monroe), and we related diets to benthic prey availability at these lakes. Black crappies in Lake Monroe obtained the largest size at age, whereas those in Lake Marian had the smallest size at age. Black crappies in Lakes Lochloosa and Marian consistently exhibited positive selection of dipteran pupae; fish in Lake Monroe showed consistently positive selection of a higher‐quality prey item (the mysid shrimp Americamysis almyra) that was not available in Lakes Lochloosa and Marian. A similarity index indicated that benthic prey availability influenced consumption of benthic prey items by black crappies in all three lakes. Differences in prey availability (i.e., density and presence‐absence) and prey selection influenced diet composition and ontogenetic diet shifts of black crappies. Diet and prey availability differences among lakes probably contributed to the variation in black crappie growth rates; the highest growth was observed at Lake Monroe, where the additional prey resource (A. almyra) was available.
Larval Metamorphosis of Individual Pacific Lampreys Reared in Captivity
Authors: McGree Michelle , Whitesel Timothy A. , Stone Jen 
Published: December 2008

AbstractThis study is one of the first to follow individual Pacific lampreys Lampetra tridentata through the process of metamorphosis. Readily observable external changes were described for 13 individual Pacific lampreys undergoing metamorphosis. Changes occurred to the mouth, eyes, and branchial region from July to at least November. During metamorphosis, Pacific lampreys also exhibited asymmetric growth, including an increase in snout depth, that had not previously been reported in the literature. The order of the morphological changes and the patterns of asymmetric growth in the Pacific lamprey closely matched those reported for another Lampetra species, the American brook lamprey L. appendix, but exhibited unexpected variations from those reported in other species of lampreys. Excepting one catastrophic event, under captive rearing conditions 96.4% of the ammocoetes survived and the maximum growth rates of 0.040‐0.071 mm/d were within the range of those estimated for ammocoetes rearing naturally in stream environments. Supplemental feeding improved larval growth but did not influence the incidence of metamorphosis in captively reared animals. To develop effective conservation strategies for Pacific lampreys in the Columbia River basin, it would be prudent to consider that metamorphosis, a time when the animals are relatively vulnerable, may last from July to December.
Use of Microsatellites to Determine Population Structure and Migration of Pacific Herring in British Columbia and Adjacent Regions
Authors: Beacham T. D. , Schweigert J. F. , MacConnachie C. , Le K. D. , Flostrand L. 
Published: December 2008

AbstractThis study assessed genetic population structure of Pacific herring Clupea pallasii in British Columbia and adjacent regions by analyzing microsatellite variation; the utility of microsatellites for stock identification applications was also evaluated. Variation at 14 loci was surveyed in approximately 26,000 Pacific herring from 90 sampling locations. Estimates of the genetic differentiation index FST by locus varied between 0.000 and 0.014, and the mean across all loci was 0.003. Four stocks of Pacific herring were defined in British Columbia, and stocks were also identified in southeast Alaska, Washington, and California. In British Columbia, differences in timing of spawning are the main isolating mechanisms among stocks, although geographic isolation of the spawning populations may also have some effect in maintaining the genetic distinctiveness of each stock. The limited genetic differentiation among Pacific herring populations in British Columbia is consistent with among‐population straying rates that are sufficient to homogenize allele frequencies over broad areas. Analysis of simulated mixtures from fishery sampling suggested that acceptable estimates of stock composition were achieved by use of the microsatellites. Mixed‐stock samples (∼1,700 individuals) were collected during research vessel surveys from 14 locations in British Columbia. Analysis of summer mixed‐stock samples from the Strait of Georgia and adjacent waters indicated that resident fish on the west side of the strait were mainly derived from primary‐spawning populations (i.e., those that spawned during the primary period in March) that failed to migrate to traditional summer feeding grounds. On the east side of the strait, Pacific herring of mainland inlet origin were found in higher proportions and presumably did not move in appreciable numbers to feeding areas off the west coast of Vancouver Island. In northern British Columbia, fish from northern late‐spawning populations dominated fishery samples collected in waters adjacent to the mainland until the end of June; however, by late July, this group had been replaced almost entirely by primary‐spawning Pacific herring of British Columbia origin.
Effect of secretagogues on cytosolic free Ca2+ and insulin release in the hamster clonal β-cell line HIT-T15
Authors: Hughes S. J. , Ashcroft S. J. H. 
Published: December 2008

ABSTRACT
We have examined the effect of secretagogues on cytosolic free Ca2+ (Cai) in the hamster clonal β-cell line HIT-T15 using the Ca2+-binding fluorescent indicator Quin 2. Stimulation of HIT cells by glucose increased Cai in a dose-dependent manner; raising the medium glucose concentration from zero to 2 mm increased Cai by 36%, from 89 ± 4 to 121 ± 6 nm (mean ± s.e.m., n = 23). Further raising the medium glucose concentration to 10 mm increased Cai to 139 ± 6 nm. Cai was maximum and plateaued at 4 min after each addition of glucose. Addition of 40 mm K+ to the medium rapidly depolarized the HIT cells and increased Cai to 407 ± 48 nm. The increases in Cai in response to glucose or K+ were blocked by the simultaneous presence of verapamil (50μm). Stimulation by glucose or K+ also increased insulin release in parallel incubations of Quin 2-loaded HIT cells. Carbamylcholine chloride, forskolin or the phorbol ester 12-O-tetradecanoylphorbol acetate had no significant effect on Cai in glucose-stimulated HIT cells monitored 5 min after the addition of each test agent, despite increasing insulin release by 241, 239 and 216% respectively. These data support the hypothesis that potentiators of insulin release which activate cAMP-dependent protein kinase or protein kinase C do not increase Cai but sensitize the secretory mechanism to Ca2+.
Is intracellular pH a coupling factor in nutrient-stimulated pancreatic islets?
Authors: Best L. , Bone E. A. , Meats J. E. , Tomlinson S. 
Published: December 2008

ABSTRACT
Intracellular pH (pHi) was monitored in dispersed pancreatic islet cells from rats using the fluorescent dye 2′7′bis-carboxyethyl-5′(6′)-carboxyfluorescein. The addition of a weak acid (acetate, propionate or formate) provoked a rapid fall in pHi, corresponding to approximately 0·2 units, followed by a slower return to the basal value. Amiloride also caused a rapid fall in pHi, but no recovery occurred in this case. Addition of NH4Cl induced a rise in pHi. Of the nutrients tested, only glyceraldehyde produced a fall in pHi, both glucose and α-ketoisocaproate causing a gradual and sustained rise in pHi.
Insulin secretion and inositol lipid metabolism in response to nutrient stimuli were markedly inhibited by NH4Cl. The responses to non-nutrient stimuli were unaffected. Glucose-induced insulin secretion and inositol lipid metabolism were potentiated in the presence of amiloride. No such potentiation, however, was observed in the presence of weak acids.
Amiloride and weak acids shared the ability to reduce the fractional outflow rate of 45Ca2+.
It is concluded that pharmacological manipulations of pHi can influence certain aspects of islet cell function, such as calcium handling, though it seems unlikely that the stimulation of islets by nutrient secretagogues occurs as a result of changes in pHi.
Pro-opiomelanocortin mRNA size heterogeneity in ACTH-dependent Cushing's syndrome
Authors: Clark A. J. L. , Lavender P. M. , Besser G. M. , Rees L. H. 
Published: December 2008

ABSTRACT
As an approach to understanding the abnormalities of pro-opiomelanocortin (POMC) gene regulation in human ACTH-secreting tumours, we have analysed the POMC mRNA content of nine such tumours using the Northern blot technique. Most of the tumours and normal human pituitary contained easily detectable quantities of POMC mRNA. The length of this message in most tumours was similar to, or slightly larger than, that in the normal pituitary (1150–1200 bases). Ribonuclease H studies suggested that the origin of any size heterogeneity was a longer poly(A) tail in the tumour RNA. Some tumours, however, expressed a short POMC mRNA (800 bases) which may lack the first two exons of the POMC gene as has been described. A third POMC mRNA size variant (1500 bases) was also seen in low levels in two cases, and as the principal mRNA species in one case. Primer extension and S1 nuclease protection studies suggested that most transcripts in the tumours analysed originated from the conventional promoter, and thus the use of an alternative promoter is not an adequate explanation for the expression of this gene in ectopic ACTH-secreting tumours.
Molecular cloning and sequence analysis of putative chicken prolactin cDNA
Authors: Hanks M.C. , Alonzi J.A. , Sharp P.J. , Sang H.M. 
Published: December 2008

ABSTRACT
A cDNA library was prepared from mRNA isolated from anterior pituitary glands of incubating bantam hens, in which prolactin mRNA levels were predicted to be very high. Nine clones, representing abundant mRNA species, were identified and shown to contain homologous sequences. Two clones, of 871 bp and 580 bp, were analysed by DNA sequencing. The shorter clone was found to be a truncated cDNA product but otherwise identical to the longer clone. The 871 bp cDNA, PRL101, contains an open reading frame capable of encoding a polypeptide of 229 amino acids. This putative polypeptide has a high degree of homology to mammalian prolactins (approximately 70%), strongly suggesting that PRL101 encodes chicken preprolactin. The protein was predicted to have a 30 amino acid signal sequence which would be cleaved off to give a mature protein of 199 amino acids. The peptide sequence also had a 26% homology to chicken growth hormone, which is related to prolactin. This similarity confirms the conclusion that PRL101 is a chicken prolactin cDNA clone. An abundant mRNA of approximately 880 b was detected in poly(A)+ RNA from pituitary glands probed with PRL101. Analysis of chicken genomic DNA showed that there is one copy of the prolactin gene in the genome. PRL101 hybridized strongly to genomic DNA from closely related galliforms (quail and turkey) and less strongly to DNA from more distantly related species (duck and ring dove).
Heterogeneity of responses to LH-releasing hormone and phorbol ester among rat gonadotrophs: a study using a reverse haemolytic plaque assay for LH
Authors: Lewis C. E. , Richards P. S. M. , Morris J. F. 
Published: December 2008

ABSTRACT
Protein kinase C (PK-C) has been implicated in the action of LHRH because LHRH-induced release of LH is partially mimicked by phorbol esters which activate PK-C, and reduced in magnitude by inhibitors of PK-C. We have used a reverse haemolytic plaque assay for LH to visualize and compare the direct effects on individual rat gonadotrophs of (1) a 2-h exposure to a range of concentrations of LHRH and phorbol 12-myristate 13-acetate (PMA) and (2) a single maximally stimulatory dose (10 nm) of LHRH or PMA, or LHRH in the presence of inhibitors of PK-C (retinal and isoquinolone sulphonamide; H7) over six consecutive 30-min intervals.
Quantitative analysis of the size and number of haemolytic plaques indicated that LHRH induced a dose- and time-dependent increase in the amount of LH released by individual gonadotrophs, with no evidence of the priming effect of LHRH. Stimulation by 10 nm LHRH induced recruitment of actively secreting gonadotrophs which reached maximum levels by 90 min. There was a delay of 90–120 min before 10 nm PMA caused a significant release of LH, as assessed by both the size and number of plaques. During the first 30 min of exposure, the presence of 10 μm retinal or H7 augmented LHRH-induced secretion of LH, with the absence of any inhibition of the effects of LHRH until 90–120 min, when both the size and number of plaques were reduced compared with those formed in the presence of LHRH alone.
Heterogeneity of responsiveness to LHRH among gonadotrophs was evident from the bimodal distribution of plaque sizes formed after 60–180 min of exposure to LHRH. The size of gonadotrophs was correlated with that of plaques by 60 min of exposure to LHRH, with the larger cells secreting more LH. By contrast, not until 180 min did PMA induce such heterogeneity in secretion. PMA or LHRH in the presence of retinal or H7 resulted in only a unimodal distribution of plaque sizes, with the absence of a discrete population of cells producing the larger plaques.
These findings indicate that PK-C is not crucial for the immediate LH-releasing action of LHRH but could well be involved in other, slower LHRH-induced effects such as post-translational modification of LH, up-regulation of LHRH receptors and/or gonadotroph multiplication.
Specific effects of agonists of the calcium messenger system on secretion of 'late-pathway' steroid products by intact tissue and dispersed cells of the rat adrenal zona glomerulosa
Authors: Vinson G. P. , Laird S. M. , Whitehouse B. J. , Hinson J. P. 
Published: December 2008

ABSTRACT
Recent data have implicated the phosphatidylinositol/calcium second-messenger system in the control of aldosterone secretion by the adrenal zona glomerulosa. However, in the rat adrenal there are few reports of a direct effect of protein kinase C activation on steroid secretion, while the effects of calcium mobilization may be variable. Since the rat adrenal zona glomerulosa is sensitive to the mode of tissue preparation, these mechanisms were reinvestigated in intact (non-dispersed) capsular tissue and collagenase-dispersed zona glomerulosa cells.
Steroidogenesis in the intact zona glomerulosa was markedly affected by agonists of the calcium messenger system. Most notably, aldosterone and 18-hydroxycorticosterone (18-OH-B) secretion were stimulated by A23187 (100 nmol to 10 μmol/l) and BAY K 8644 (500 nmol/l). Phorbol 12-myristate 13-acetate (TPA; 1 pmol to 1 μmol/l) stimulated aldosterone secretion at all doses and caused a dose-dependent increase in 18-OH-B and 18-hydroxydeoxycorticosterone (18-OH-DOC) secretion. Corticosterone secretion was slightly increased in the presence of A23187 but not by TPA or BAY K 8644. Production of 18-OH-DOC was unaffected by A23187 and BAY K 8644. The calcium channel antagonist verapamil (10 μmol/l) inhibited ACTH-stimulated aldosterone secretion by the intact zona glomerulosa but had no effect on corticosterone secretion.
Verapamil (10 μmol/l) also inhibited the increase in aldosterone secretion by collagenase-dispersed zona glomerulosa cells stimulated by ACTH (100 fmol to 100 nmol/l), angiotensin II (100 pmol to 10 nmol/l) and potassium (5·9 and 8·4 mmol/l); stimulated corticosterone secretion was unaffected. Aldosterone secretion by dispersed zona glomerulosa cells was unaffected by the calcium ionophore A23187 (10 nmol to 100 μmol/l) or by TPA (1 nmol to 10 μmol/l). Corticosterone secretion was also unaffected by A23187 over the same dose range, but was increased slightly by high doses of TPA (10 and 1 μmol/l), while the calcium channel agonist BAY K 8644 had no effect on either steroid.
The results show that calcium mobilization and protein kinase C activation can stimulate steroid secretion in the rat adrenal zona glomerulosa and that large and reproducible effects are seen when intact tissue is used. In general only 18-OH-B and aldosterone secretion were affected; effects on corticosterone and 18-OH-DOC were much less marked. Together with the effects of calcium blockers, the data strongly support the view that protein kinase C activation and calcium mobilization are primarily involved in the control of the 'late pathway' of aldosterone biosynthesis.
STRUCTURAL ORGANIZATION OF THE HUMAN ANDROGEN RECEPTOR GENE
Authors: Kuiper G.G.J.M. , Faber P.W. , van Rooij H.C.J. , van der Korput J.A.G.M. , Ris-Stalpers C. , Klaassen P. , Trapman J. , Brinkmann A.O. 
Published: December 2008

ABSTRACT
The complete coding region of the human androgen receptor gene has been isolated from a genomic library. The information for the androgen receptor was found to be divided over eight exons and the total length of the gene exceeded 90 kb. The sequence encoding the N-terminal region is present in one large exon. The two putative DNA-binding fingers are encoded separately by two small exons. The information for the hormone-binding domain is split over five exons. Positions of introns are identical to those reported for the chicken progesterone receptor and the human oestrogen receptor genes. Southern blot analysis of genomic DNA with various specific probes reveal that the human androgen receptor is encoded by a single-copy gene.
Activation of the thyroid peroxidase gene in human thyroid cells: effect of thyrotrophin, forskolin and phorbol ester
Authors: Collison K. S. , Banga J. P. , Barnett P. S. , Kung A. W. C. , McGregor A. M. 
Published: December 2008

ABSTRACT
The enzyme thyroid peroxidase (TPO) plays a central role in thyroid hormone synthesis and is the target for the autoimmune attack in lymphocytic thyroiditis. We have examined the activation of the TPO gene in cultured human thyrocytes using slotblot hybridization with a synthetic 40 mer oligonucleotide probe derived from the nucleotide sequence of the human TPO gene. The oligonucleotide probe was shown by Northern blotting to hybridize specifically to an approximately 3 kb RNA species from thyroid tissue of patients with Graves' disease, but not to RNA preparations from human or bovine retinal tissue, providing compelling evidence for the specificity of the probe for TPO mRNA. Addition of TSH (10 mU/ml) to primary thyroid cultures for 4 h led to increased TPO mRNA levels which were maximal after 48 h and significantly higher than basal even after 7 days of co-culture. Activation of TPO mRNA by TSH showed dose dependency over a wide range (0·01–100 mU/ml), with a maximal effect at 10 mU TSH/ml in cells cultured for a period of 72 h.
Comparison of TPO mRNA levels with the accumulation of thyroglobulin mRNA levels following stimulation by TSH indicated that the induction of the gene encoding thyroglobulin precedes transcription of the TPO gene. The adenylate cyclase activator forskolin (1–100 μm) mimicked TSH in increasing TPO mRNA levels whilst, in contrast, the phorbol ester 12-O-tetradecanoyl phorbol 13-acetate (TPA; 0·01–1 μm) led to levels of TPO mRNA that were lower than basal. Thus TSH induces a specific dose-dependent activation of TPO mRNA which is mimicked by agents which increase cyclic AMP. In contrast, TPA-induced activation of protein kinase C inhibits this response.
Expression of biologically active recombinant-derived chicken prolactin in Escherichia coli
Authors: Hanks M. C. , Talbot R. T. , Sang H. M. 
Published: December 2008

ABSTRACT
The putative chicken prolactin (chPRL) cDNA clone PRL101 was manipulated in vitro and cloned into the Escherichia coli expression vector pKK233-2 to produce a plasmid coding for recombinant-derived mature chPRL (R-chPRL). Expression of this manipulated cDNA sequence in E. coli resulted in the production of a 23 kDa protein which cross-reacted with specific chPRL antisera in Western blots. The partially purified protein stimulated ring dove crop sac mucosa to proliferate in a PRL bioassay, demonstrating that the R-chPRL was biologically active. R-chPRL was expressed at a level of approximately 1·5% of total cell protein.