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See detailThe HMG-Box Transcription Factor Sox4b Is Required for Pituitary Expression of gata2a and Specification of Thyrotrope and Gonadotrope Cells in Zebrafish.
Quiroz O'Donova, Yobhana ULg; Lopez, Marie-Josée ULg; Mavropoulos, A et al

in Molecular Endocrinology (2012), 26(6), 1014-1027

The pituitary is a complex gland comprising different cell types each secreting specific hormones. The extensive network of signaling molecules and transcription factors required for determination and ... [more ▼]

The pituitary is a complex gland comprising different cell types each secreting specific hormones. The extensive network of signaling molecules and transcription factors required for determination and terminal differentiation of specific cell types is still not fully understood. The SRY-like HMG-box (SOX) transcription factor Sox4 plays important roles in many developmental processes and has two homologs in zebrafish, Sox4a and Sox4b. We show that the sox4b gene is expressed in the pituitary anlagen starting at 24 h after fertilization (hpf) and later in the entire head region including the pituitary. At 48 hpf, sox4b mRNA colocalizes with that for TSH (tshbeta), glycoprotein subunit alpha (gsualpha), and the Zn finger transcription factor Gata2a. Loss of Sox4b function, using morpholino knockdown or expression of a dominant-negative Sox4 mutant, leads to a drastic decrease in tshbeta and gsualpha expression and reduced levels of gh, whereas other anterior pituitary gland markers including prl, slbeta, pomc, and lim3 are not affected. Sox4b is also required for expression of gata2a in the pituitary. Knockdown of gata2a leads to decreased tshbeta and gsualpha expression at 48 hpf, similar to sox4b morphants. Injection of gata2a mRNA into sox4b morphants rescued tshbeta and gsualpha expression in thyrotrope cells. Finally, sox4b or gata2a knockdown causes a significant decrease of gonadotropin expression (lhbeta and fshbeta) at 4 d after fertilization. In summary, our results indicate that Sox4b is expressed in zebrafish during pituitary development and plays a crucial role in the differentiation of thyrotrope and gonadotrope cells through induction of gata2a expression in the developing pituitary. [less ▲]

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See detailThe angiostatic 16K human prolactin overcomes endothelial cell anergy and promotes leukocyte infiltration via nuclear factor-kappaB activation
Tabruyn, Sébastien ULg; Sabatel, Céline ULg; Nguyen, Ngoc-Quynh-Nhu ULg et al

in Molecular Endocrinology (2007), 21(6), 1422-9

The 16-kDa N-terminal fragment of human prolactin (16K hPRL) is a potent angiostatic factor that inhibits tumor growth in mouse models. Using microarray experiments, we have dissected how the endothelial ... [more ▼]

The 16-kDa N-terminal fragment of human prolactin (16K hPRL) is a potent angiostatic factor that inhibits tumor growth in mouse models. Using microarray experiments, we have dissected how the endothelial-cell genome responds to 16K hPRL treatment. We found 216 genes that show regulation by 16K hPRL, of which a large proportion turned out to be associated with the process of immunity. 16K hPRL induces expression of various chemokines and endothelial adhesion molecules. These expressions, under the control of nuclear factor-kappaB, result in an enhanced leukocyte-endothelial cell interaction. Furthermore, analysis of B16-F10 tumor tissues reveals a higher expression of adhesion molecules (intercellular adhesion molecule 1, vascular cell adhesion molecule 1, or E-selectin) in endothelial cells and a significantly higher number of infiltrated leukocytes within the tumor treated with 16K hPRL compared with the untreated ones. In conclusion, this study describes a new antitumor mechanism of 16K hPRL. Because cellular immunity against tumor cells is a crucial step in therapy, the discovery that treatment with 16K hPRL overcomes tumor-induced anergy may become important for therapeutic perspectives. [less ▲]

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See detailThe antiangiogenic factor, 16-kDa human prolactin, induces endothelial cell cycle arrest by acting at both the G(0)-G(1) and the G(2)-M phases
Tabruyn, Sébastien ULg; Nguyen, Ngoc-Quynh-Nhu ULg; Cornet, Anne ULg et al

in Molecular Endocrinology (2005), 19(7), 1932-1942

The 16-kDa N-terminal fragment of human prolactin (16K hPRL) is a potent antiangiogenic factor that has been shown to prevent tumor growth in a xenograph mouse model. In this paper we first demonstrate ... [more ▼]

The 16-kDa N-terminal fragment of human prolactin (16K hPRL) is a potent antiangiogenic factor that has been shown to prevent tumor growth in a xenograph mouse model. In this paper we first demonstrate that 16K hPRL inhibits serum-induced DNA synthesis in adult bovine aortic endothelial cells. This inhibition is associated with cell cycle arrest at both the G(0)-G(1) and the G(2)-M phase. Western blot analysis revealed that 16K hPRL strongly decreases levels of cyclin D1 and cyclin B1, but not cyclin E. The effect on cyclin D1 is at least partially transcriptional, because treatment with 16K hPRL both reduces the cyclin D1 mRNA level and down-regulates cyclin D1 promoter activity. This regulation may be due to inhibition of the MAPK pathway, but it is independent of the glycogen synthase kinase-3 beta pathway. Lastly, 16K hPRL induces the expression of negative cell cycle regulators, the cyclin-dependent kinase inhibitors p21(cip1) and p27(kip1). In summary, 16K hPRL inhibits serum-induced proliferation of endothelial cells through combined effects on positive and negative regulators of cell cycle progression. [less ▲]

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See detailCathepsin D processes human prolactin into multiple 16K-like N-terminal fragments: Study of their antiangiogenic properties and physiological relevance
Piwnica, David; Touraine, Philippe; Struman, Ingrid ULg et al

in Molecular Endocrinology (2004), 18(10), 2522-2542

16K prolactin (PRL) is the name given to the 16-kDa N-terminal fragment obtained by proteolysis of rat PRL by tissue extracts or cell lysates, in which cathepsin D was identified as the candidate protease ... [more ▼]

16K prolactin (PRL) is the name given to the 16-kDa N-terminal fragment obtained by proteolysis of rat PRL by tissue extracts or cell lysates, in which cathepsin D was identified as the candidate protease. Based on its antiangiogenic activity, 16K PRL is potentially a physiological inhibitor of tumor growth. Full-length human PRL ( hPRL) was reported to be resistant to cathepsin D, suggesting that antiangiogenic 16K PRL may be physiologically irrelevant in humans. In this study, we show that hPRL can be cleaved by cathepsin D or mammary cell extracts under the same conditions as described earlier for rat PRL, although with lower efficiency. In contrast to the rat hormone, hPRL proteolysis generates three 16K-like fragments, which were identified by N-terminal sequencing and mass spectrometry as corresponding to amino acids 1 - 132 ( 15 kDa), 1 - 147 (16.5 kDa), and 1 - 150 ( 17 kDa). Biochemical and mutagenetic studies showed that the species-specific digestion pattern is due to subtle differences in primary and tertiary structures of rat and human hormones. The antiangiogenic activity of N-terminal hPRL fragments was assessed by the inhibition of growth factor-induced thymidine uptake and MAPK activation in bovine umbilical endothelial cells. Finally, an N-terminal hPRL fragment comigrating with the proteolytic 17-kDa fragment was identified in human pituitary adenomas, suggesting that the physiological relevance of antiangiogenic N-terminal hPRL fragments needs to be reevaluated in humans. [less ▲]

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See detailThe antiangiogenic factor 16K human prolactin induces caspase-dependent apoptosis by a mechanism that requires activation of nuclear factor-kappa B
Tabruyn, Sébastien ULg; Sorlet, C. M.; Rentier-Delrue, Françoise ULg et al

in Molecular Endocrinology (2003), 17(9), 1815-1823

We have previously shown that the 16-kDa N-terminal fragment of human prolactin (16K hPRL) has antiangiogenic properties, including the ability to induce apoptosis in vascular endothelial cells. Here, we ... [more ▼]

We have previously shown that the 16-kDa N-terminal fragment of human prolactin (16K hPRL) has antiangiogenic properties, including the ability to induce apoptosis in vascular endothelial cells. Here, we examined whether the nuclear factor-kappaB (NF-kappaB) signaling pathway was involved in mediating the apoptotic action of 16K hPRL in bovine adrenal cortex capillary endothelial cells. In a dose-dependent manner, treatment with 16K hPRL induced inhibitor kappaB-alpha degradation permitting translocation of NF-kappaB to the nucleus and reporter gene activation. Inhibition of NF-kappaB activation by overexpression of a nondegradable inhibitor kappaB-alpha mutant or treatment with NF-kappaB inhibitors blocked 16K hPRL-induced apoptosis. Treatment with 16K hPRL activated the initiator caspases-8 and -9 and the effector caspase-3, all of which were essential for stimulation of DNA fragmentation. This activation of the caspase cascade by 16K hPRL was also NF-kappaB dependent. These findings support the conclusion that NF-kappaB signaling plays a central role in 16K hPRL-induced apoptosis in vascular endothelial cells. [less ▲]

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See detailAndrogen-driven prostate epithelial cell proliferation and differentiation in vivo involve the regulation of p27.
Waltregny, David ULg; Leav, Irwin; Signoretti, Sabina et al

in Molecular Endocrinology (2001), 15(5), 765-82

Androgens control both growth and differentiation of the normal prostate gland. However, the mechanisms by which androgens act upon the cell cycle machinery to regulate these two fundamental processes are ... [more ▼]

Androgens control both growth and differentiation of the normal prostate gland. However, the mechanisms by which androgens act upon the cell cycle machinery to regulate these two fundamental processes are largely unknown. The cyclin-dependent kinase (cdk) inhibitor p27 is a negative cell cycle regulator involved in differentiation-associated growth arrest. Here, we investigate the role and regulation of p27 in the testosterone proprionate (TP)-stimulated regeneration of the ventral prostate (VP) of castrated rats. Continuous TP administration to castrated rats triggered epithelial cell proliferation, which peaked at 72 h, and then declined despite further treatment. Castration-induced atrophy of the VP was associated with a significant increase in p27 expression as compared with the VP of intact animals. Twelve hours after the initiation of androgen treatment, total p27 levels as well as its fraction bound to cdk2, its main target, significantly dropped in the VP of castrated rats. Thereafter, concomitantly to the induction of epithelial cell proliferation, the glandular morphology of VP was progressively restored at 48-96 h of TP treatment. During this period of the regenerative process, whereas both proliferating basal and secretory epithelial cells did not express p27, the protein was selectively up-regulated in the nonproliferating secretory epithelial compartment. This up-regulation of p27 expression was coincident with an increase in its association with, and presumably inhibition of, cdk2. At each time point of TP treatment, p27 abundance in the VP was inversely correlated with the level of its proteasome-dependent degradation activity measured in vitro in VP lysates, whereas only slight changes in the amount of p27 transcripts were detected. In addition, the antiandrogen flutamide blocked maximal TP-induced p27 degradation completely. Finally, the expression of skp2, the ubiquitin ligase that targets p27 for degradation, was seen to increase with androgen administration, preceding maximal proliferation and concomitantly to augmented p27 degradation activity. Taken together, our data indicate that androgens mediate both proliferation and differentiation signals in normal prostate epithelial cells in vivo, through regulation of p27. [less ▲]

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See detailThe antiangiogenic factor 16K PRL induces programmed cell death in endothelial cells by caspase activation
Martini, J. F.; Piot, C.; Humeau, L. M. et al

in Molecular Endocrinology (2000), 14(10), 1536-49

We asked whether the antiangiogenic action of 16K human PRL (hPRL), in addition to blocking mitogen-induced vascular endothelial cell proliferation, involved activation of programmed cell death. Treatment ... [more ▼]

We asked whether the antiangiogenic action of 16K human PRL (hPRL), in addition to blocking mitogen-induced vascular endothelial cell proliferation, involved activation of programmed cell death. Treatment with recombinant 16K hPRL increased DNA fragmentation in cultured bovine brain capillary endothelial (BBE) and human umbilical vein endothelial (HUVE) cells in a time- and dose-dependent fashion, independent of the serum concentration. The activation of apoptosis by 16K hPRL was specific for endothelial cells, and the activity of the peptide could be inhibited by heat denaturation, trypsin digestion, and immunoneutralization, but not by treatment with the endotoxin blocker, polymyxin-B. 16K hPRL-induced apoptosis was correlated with the rapid activation of caspases 1 and 3 and was blocked by pharmacological inhibition of caspase activity. Caspase activation was followed by inactivation of two caspase substrates, poly(ADP-ribose) polymerase (PARP) and the inhibitor of caspase-activated deoxyribonuclease (DNase) (ICAD). Furthermore, 16K hPRL increased the conversion of Bcl-X to its proapoptotic form, suggesting that the Bcl-2 protein family may also be involved in 16K hPRL-induced apoptosis. These findings support the hypothesis that the antiangiogenic action of 16K hPRL includes the activation of programmed cell death of vascular endothelial cells. [less ▲]

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See detailAt Least Three Subdomains of V-Erba Are Involved in Its Silencing Function
Busch, Kerstin; Martin, Bernd; Baniahmad, Aria et al

in Molecular Endocrinology (1997), 11(3), 379-89

Several members of the thyroid hormone receptor (TR) family are able to switch from a transcriptional repressor to a transcriptional activator upon binding of their ligand. The oncogene v-erbA is a ... [more ▼]

Several members of the thyroid hormone receptor (TR) family are able to switch from a transcriptional repressor to a transcriptional activator upon binding of their ligand. The oncogene v-erbA is a variant form of the TR unable to bind hormone and thus acts as a constitutive repressor. We demonstrate, using fusion proteins between the DNA-binding domain of the yeast factor GAL4 and the silencing domains of v-erbA and TR beta, that point mutations in three different regions severely affect their repression function. Furthermore, the three regions, each as an inactive fusion protein with the GAL4 DNA-binding domain, restore silencing activity when assembled on the same promoter. These observations define at least three silencing subdomains, SSD1-SSD3, which are involved in the silencing function of v-erbA. We propose a model in which full silencing activity is brought about by the combined interaction of each silencing subdomain with corepressors and/or basal transcription factors. [less ▲]

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See detailCharacterization of an up-stream promoter directing extrapituitary expression of the human prolactin gene
Berwaer, M.; Martial, Joseph ULg; Davis, J. R.

in Molecular Endocrinology (1994), 8(5), 635-42

The human PRL gene is expressed outside pituitary lactotrophs in decidualized endometrium and lymphoid cells, but here the mRNA contains a 5'-untranslated region from an additional noncoding exon 1a. We ... [more ▼]

The human PRL gene is expressed outside pituitary lactotrophs in decidualized endometrium and lymphoid cells, but here the mRNA contains a 5'-untranslated region from an additional noncoding exon 1a. We have isolated a genomic DNA clone containing human PRL exon 1a with 2800 basepairs (bp) of 5'-flanking sequences. Sequencing locates exon 1a -5840 bp up-stream of the pituitary start site. To study its suspected regulatory function, various lengths of the 5'-flanking region were linked to the luciferase (Luc) reporter gene. Their ability to direct gene expression has been analyzed in transfection studies. The proximal 1620 bp of promoter sequence directed Luc expression in the T-lymphoid Jurkat cell line, and this was unaffected by 5'-deletion to the proximal 453 bp. However, further 5'-deletion to the most proximal 67 bp drastically reduced this activity by 90%. The exon 1a promoter was inactive in pituitary GH3 cells and HeLa cells; in contrast, the exon 1b pituitary promoter, active in GH3 cells, was inactive in Jurkat cells. DNase-I footprinting studies and further 5'- and 3'-deletion analysis identified factor-binding sites within an enhancer element located at -375/-212 bp, which contributed approximately 50% of the promoter activity. [less ▲]

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See detailInsulin expression in pancreatic islet cells relies on cooperative interactions between the helix loop helix factor E47 and the homeobox factor STF-1.
Peers, Bernard ULg; Sharma, S.; Teitelman, G. et al

in Molecular Endocrinology (1994), 8(12), 1798-806

The development of endocrine cell types within the pancreas is thought to involve the progressive restriction of pluripotential stem cells, which gives rise to the four major cell types: insulin ... [more ▼]

The development of endocrine cell types within the pancreas is thought to involve the progressive restriction of pluripotential stem cells, which gives rise to the four major cell types: insulin-, glucagon-, somatostatin-, and pancreatic polypeptide-expressing cells. The mechanism by which these peptide hormone genes are induced and then either maintained or repressed during development is unknown, but their coexpression in early precursor cells suggests the involvement of common regulatory factors. Here we show that the somatostatin transcription factor STF-1 is also a principal regulator of insulin expression in beta-cells of the pancreas. STF-1 stimulates the insulin gene by recognizing two well defined islet-specifying elements on the insulin promoter and by subsequently synergizing in trans with the juxtaposed helix-loop-helix protein E47. Within the STF-1 protein, an N-terminal trans-activation domain functions cooperatively with E47 to stimulate insulin transcription. As truncated STF-1 polypeptides lacking the N-terminal activation domain strongly inhibit insulin promoter activity in beta-islet cells, our results suggest that the specification of islet cell types during development may be in part determined by the expression of STF-1 relative to other islet cell factors. [less ▲]

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See detailOkadaic acid, a protein phosphatase inhibitor, enhances transcription of a receptor gene containing sequence A of the human prolactin promoter
Wera, S.; Belayew, A.; Martial, Joseph ULg

in Molecular Endocrinology (1993), 7(8), 965-71

Human PRL (hPRL) gene expression is controlled by cAMP and Ca2+. This control is mediated by two cis-elements: a Pit-1 binding site (-62 to -35) and sequence A (-110 to -85), present in the hPRL promoter ... [more ▼]

Human PRL (hPRL) gene expression is controlled by cAMP and Ca2+. This control is mediated by two cis-elements: a Pit-1 binding site (-62 to -35) and sequence A (-110 to -85), present in the hPRL promoter. We have investigated whether protein phosphatases could be involved in this regulation. GC-type rat pituitary tumor cells were transfected with sequence -138 to -35 of the hPRL gene promoter, upstream from a thymidine kinase promoter and a chloramphenicol acetyltransferase (CAT) reporter gene. Addition of okadaic acid (OA), a specific inhibitor of protein phosphatases 1 and 2A, stimulates transient expression of the CAT gene. The dose-response curve shows a maximal effect at 25 nM OA (2.2-fold stimulation above controls). The OA effect is also observed with a natural 4500-base pair hPRL promoter. A single copy of the hPRL promoter sequence -115 to -85 (sequence A) confers to a thymidine kinase-CAT construct an identical response to OA, whereas a single copy of the proximal Pit-1 binding site does not. Synergism is observed between cAMP and OA in activating PRL gene transcription. This synergism is also observed with a single copy of sequence A. The effect of cAMP is not mediated by an L-type Ca2+ channel, since addition of the Ca2+ channel antagonist verapamil does not decrease it, nor does complexing extracellular Ca2+ significantly reduce it. Furthermore, OA and the Ca2+ channel opener BAY K8644 exert additive effects. [less ▲]

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See detailCharacterization of somatostatin transactivating factor-1, a novel homeobox factor that stimulates somatostatin expression in pancreatic islet cells.
Peers, Bernard ULg; Johnson, T.; Ferreri, K. et al

in Molecular Endocrinology (1993), 7(10), 1275-83

The endocrine pancreas consists of several differentiated cell types that are distinguished by their selective expression of peptide hormones such as insulin, glucagon, and somatostatin. Although a number ... [more ▼]

The endocrine pancreas consists of several differentiated cell types that are distinguished by their selective expression of peptide hormones such as insulin, glucagon, and somatostatin. Although a number of homeobox-type factors have been proposed as key regulators of individual peptide genes in the pancreas, their cellular distribution and relative abundance remain uncharacterized. Also, their overlapping DNA binding specificities have further obscured the regulatory functions these factors perform during development. In this report we characterize a novel homeobox-type somatostatin transactivating factor termed STF-1, which is uniformly expressed in cells of the endocrine pancreas and small intestine. The 283-amino acid STF-1 protein binds to tissue-specific elements within the somatostatin promoter and stimulates somatostatin gene expression both in vivo and in vitro. Remarkably, STF-1 comprises the predominant tissue-specific element-binding activity in nuclear extracts from somatostatin-producing pancreatic islet cells, suggesting that this protein may have a primary role in regulating peptide hormone expression and specifying endocrine cell lineage in the developing gut. [less ▲]

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See detailAlanine-scanning mutagenesis of human prolactin: importance of the 58-74 region for bioactivity
Goffin, V.; Norman, M.; Martial, Joseph ULg

in Molecular Endocrinology (1992), 6(9), 1381-92

We have generated 10 alanine mutants of human PRL (hPRL), a member of the PRL/GH family, to investigate the involvement of the highly conserved 58-74 region in the biological behavior of the protein. When ... [more ▼]

We have generated 10 alanine mutants of human PRL (hPRL), a member of the PRL/GH family, to investigate the involvement of the highly conserved 58-74 region in the biological behavior of the protein. When treated with polyclonal anti-hPRL antibodies, all mutants were immunologically indistinguishable from the unmodified hPRL, and circular dichroism analyses indicated that their alpha-helix content was similar to that of the unmodified hormone. Mutations C58A, K69A, and, to a lesser extent, P66A affected drastically the ability of hPRL first to bind to the lactogenic receptor and second to stimulate the proliferation of Nb2 lymphoma cells, proving the importance of the 58-74 peptide segment for hPRL bioactivity. Binding affinities of these mutants to the Nb2 lactogenic receptor have been compared to lactogenic binding data previously obtained for several mutants of hGH. The comparison reveals that the residues involved in the biological properties of the two proteins are not at topologically equivalent positions. Hence, we suggest that the binding of these hormones to the lactogenic receptors occurs through a different molecular mechanism having distinct requirements at the residue level. [less ▲]

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See detailPit-1 binding sequences permit calcium regulation of human prolactin gene expression
Hoggard, Nigel; Davis, Julian R E; Berwaer, Monique et al

in Molecular Endocrinology (1991), 5(11), 1748-54

This study examines the regulation of the human PRL (hPRL) gene promoter by intracellular calcium. Deletants of the 5'-flanking region of the hPRL gene and constructs consisting of the thymidine kinase ... [more ▼]

This study examines the regulation of the human PRL (hPRL) gene promoter by intracellular calcium. Deletants of the 5'-flanking region of the hPRL gene and constructs consisting of the thymidine kinase promoter linked to the first or second proximal Pit-1 binding site were fused to the bacterial chloramphenicol acetyl transferase (CAT) reporter gene. With the complete 5-kilobase pair (kbp) hPRL promoter sequence the calcium channel agonist Bay K8644 induced a significant 2-fold increase in CAT reporter gene expression and the antagonist verapamil a 4.5-fold reduction, using GH3 cells cultured in physiological levels of calcium. The transcriptional response to calcium influx was similar with a series of 5'-deleted hPRL-CAT constructs including those that comprised the proximal (up to 740 bp) or distal (-1300- to -1700-bp) sequences alone. When treating cells cultured in low calcium conditions the induction with the hPRL promoter increased to 5-fold on the addition of exogenous calcium and Bay K8644. The pituitary-specific expression of the hPRL gene is conferred by the interaction of the pituitary-specific factor Pit-1 with several binding sites located in the 5'-flanking DNA, of which three are located in the proximal region. This suggested that Pit-1 binding sites may be involved in the calcium response.(ABSTRACT TRUNCATED AT 250 WORDS) [less ▲]

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See detailExpression of preprotachykinin-A and neuropeptide-Y messenger RNA in the thymus
Ericsson, Anders; Geenen, Vincent ULg; Robert, François et al

in Molecular Endocrinology (1990), 4

The preprotachykinin-A gene, the common gene of mRNAs encoding both substance-P (SP) and neurokinin- A (NKA), was shown to be expressed in Sprague-Dawley rat thymus by detection of specific mRNA in gel ... [more ▼]

The preprotachykinin-A gene, the common gene of mRNAs encoding both substance-P (SP) and neurokinin- A (NKA), was shown to be expressed in Sprague-Dawley rat thymus by detection of specific mRNA in gel-blot analyses. In situ hybridization revealed dispersed PPT-A-labeled cells in sections from rat thymus, with a concentration of grains over a subpopulation of cells in the thymic medulla. Also, neuropeptide-Y mRNA-expressing cells were found in the rat thymus, primarily in the thymic medulla. Rat thymic extracts contained SP-like immunoreactivity (SP-LI), and the major part of the immunoreactivity coeluted with authentic SP and SP sulfoxide standards. SP-LI was also detected in human thymus, which contained between 0.09-0.88 ng SP-LI/ g wet wt. Evidence for translation of preprotachykinin- A mRNA in the rat thymus was obtained from the demonstration of NKA-LI in thymic cells with an epithelial-like cell morphology. Combined with previous observations on the immunoregulatory roles of tachykinin peptides and the existence of specific receptors on immunocompetent cells, the demonstration of intrathymic synthesis of NKA suggests a role for NKA-LI peptides in T-cell differentiation in the thymus. [less ▲]

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See detailEvidence of pre-prosomatostatin mRNA in human normal and tumoral anterior pituitary gland
Pagesy, P.; Li, J. Y.; Rentier-Delrue, Françoise ULg et al

in Molecular Endocrinology (1989), 3(8), 1289-94

Expression of the SRIH gene was investigated in six human normal anterior pituitaries, six GH-, three PRL-, three mixed GH/PRL-secreting and four nonsecreting adenomas. Total cellular RNA and poly(A ... [more ▼]

Expression of the SRIH gene was investigated in six human normal anterior pituitaries, six GH-, three PRL-, three mixed GH/PRL-secreting and four nonsecreting adenomas. Total cellular RNA and poly(A+) mRNAs were analyzed by dot and Northern blot hybridization to a 3'-end labeled oligonucleotide probe specific for the human pre-proSRIH mRNA. A weak but detectable pre-proSRIH hybridization signal was present in human normal anterior pituitaries and in the four groups of adenomas. The size of this pre-proSRIH mRNA was indistinguishable from that found in our hypothalamic samples and close to that described in the literature. The wide variation of the signal intensity from one case to the other in each group of the different types of normal and tumoral antehypophyseal samples prevented establishment of any correlation between the level of pre-proSRIH mRNA and the nature of the pituitary tissue. The presence of SRIH mRNA in human normal and tumoral anterior pituitary tissues provides a sound basis to substantiate the hypothesis of a SRIH biosynthesis in the human anterior pituitary gland. [less ▲]

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See detailPITUITARY-HORMONES DEPENDENT EXPRESSION OF INSULIN-LIKE GROWTH FACTOR-I AND FACTOR-II IN THE IMMATURE HYPOPHYSECTOMIZED RAT TESTIS
Closset, Jean ULg; Gothot, André ULg; SENTE, Béatrice et al

in Molecular Endocrinology (1989), 3(7), 1125-1131

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See detailDiscrepancy between prolactin (PRL) messenger ribonucleic acid and PRL content in rat fetal pituitary cells: possible role of dopamine
Hooghe-Peters, E. L.; Belayew, A.; Herregodts, P. et al

in Molecular Endocrinology (1988), 2(12), 1163-8

Data are controversial concerning the time when PRL-synthesizing cells are detected for the first time in the rat pituitary. Using a very sensitive immunocytochemical technique, we could visualize only a ... [more ▼]

Data are controversial concerning the time when PRL-synthesizing cells are detected for the first time in the rat pituitary. Using a very sensitive immunocytochemical technique, we could visualize only a few PRL cells before day 10 after birth. At that time, pituitary PRL was still 200 times less abundant than in the adult (on a tissue weight basis) whereas PRL mRNA per mg total RNA was only 80 times lower than in the adult. However, by in situ hybridization, we could demonstrate the presence of PRL mRNA in cells from fetal day 18 on. We have also followed the expression of GH gene in rat pituitary cells during development. In contrast to results obtained with PRL cells, quantitative analysis of cDNA probe hybridization to GH mRNA correlated well with measurements of immunostained cells. We found that PRL was released in the blood from fetal day 19 onwards. Thus, at that time PRL is synthesized and secreted but not stored. We therefore measured brain dopamine levels, and the data support the idea that the rise in dopamine levels after birth contributes to PRL storage. We confirmed in vitro that newborn pituitary cells can store PRL when cultured in the presence of dopamine. [less ▲]

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See detailHormone genes : Structure, evolution and expression in bacteria
Goodman, H. M.; Hallewell, R. A.; Martial, Joseph ULg et al

in Molecular Endocrinology (1979)

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