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Horm Metab Res 2003; 35(5): 282-289
DOI: 10.1055/s-2003-41303
Original Basic
© Georg Thieme Verlag Stuttgart · New York

Prolactin-Signal Transduction in Neonatal Rat Pancreatic Islets and Interaction with the Insulin-Signaling Pathway

M.  E.  C.  Amaral 1 , M.  Ueno 2 , J.  B.  Carvalheira 2 , E.  M.  Carneiro 1 , L.  A.  Velloso 2 , M.  J.  A.  Saad 2 , A.  C.  Boschero 1
  • 1 Departamento de Fisiologia e Biofísica and
  • 2 Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas, São Paulo, Brasil
Further Information

Publication History

Received 30 July 2002

Accepted after Revision 7 November 2002

Publication Date:
13 August 2003 (online)

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Abstract

During pregnancy, pancreatic islets undergo structural and functional changes in response to an increased demand for insulin. Different hormones, especially placental lactogens, mediate these adaptive changes. Prolactin (PRL) mainly exerts its biological effects by activation of the JAK2/STAT5 pathway. PRL also stimulates some biological effects via activation of IRS-1, IRS-2, PI 3-kinase, and MAPK in different cell lines. Since IRS-2 is important for the maintenance of pancreatic islet cell mass, we investigated whether PRL affects insulin-signaling pathways in neonatal rat islets. PRL significantly potentiated glucose-induced insulin secretion in islets cultured for 7 days. This effect was blocked by the specific PI 3-kinase inhibitor wortmannin. To determine possible effects of PRL on insulin-signaling pathways, fresh islets were incubated with or without the hormone for 5 or 15 min. Immunoprecipitation and immunoblotting with specific antibodies showed that PRL induced a dose-dependent IRS-1 and IRS-2 phosphorylation compared to control islets. PRL-induced increase in IRS-1/-2 phosphorylation was accompanied by an increase in the association with and activation of PI 3-kinase. PRL-induced IRS-2 phosphorylation and its association with PI 3-kinase did not add to the effect of insulin. PRL also induced JAK2, SHC, ERK1 and ERK2 phosphorylation in neonatal islets, demonstrating that PRL can activate MAPK. These data indicate that PRL can stimulate the IRSs/PI 3-kinase and SHC/ERK pathways in islets from neonatal rats.

Key words

Prolactin - Insulin - Neonatal Rat Islets - Insulin Receptors Substrates 1/2 - PI 3-Kinase - MAP-Kinase - Wortmannin

References

  • 1 Ihle J N, Witthuhn B A, Quelle F W, Yamamoto K, Thierfelder W E, Kreider B, Silvennoinen O. Signaling by the cytokine receptor superfamily: JAKs and STATs.  Trends Biochem Sci. 1994;  19 222-227
    CrossrefPubMedSearch in Google Scholar
  • 2 Bole-Feysot C, Goffin V, Edery M, Binart N, Kelly P A. Prolactin (PRL) and its receptor: actions, signal transduction pathways and phenotypes observed in PRL receptor knockout mice.  Endocr Rev. 1998;  19 225-268
    CrossrefPubMedSearch in Google Scholar
  • 3 Cousin S P, Hügl S R, Myers M G, White M F, Reifel-Miller A, Rhodes C J. Stimulation of pancreatic β-cell proliferation by growth hormone is glucose-dependent: signal transduction via Janus Kinase 2 (JAK2 )/signal transducer and activator of transcription 5 (STAT5) with no crosstalk to insulin receptor substrate-mediated mitogenic signaling.  Biochem J. 1999;  344 649-658
    CrossrefPubMedSearch in Google Scholar
  • 4 Nielsen J H, Linde S, Welinder B S, Billestrup N, Madsen O D. Growth hormone is a growth factor for the differentiated pancreatic beta-cell.  Mol Endocrinal. 1989;  3 165-173
    PubMedSearch in Google Scholar
  • 5 Freeman M E, Kanyicska B, Lerant A, Nagy G. Prolactin: structure, function, and regulation of secretion.  Physiol Rev. 2000;  80 1523-1631
    CrossrefPubMedSearch in Google Scholar
  • 6 Erwin R A, Kirken R A, Malabarba M G, Farrar W L, Rui H. Prolactin activates Ras via signaling protein SHC, growth factor fereceptor bound 2, and Son of Sevenless.  Endocrinology. 1995;  156 3512-3518
    PubMedSearch in Google Scholar
  • 7 Goupille O, Barnier J-V, Guibert B, Paly J, Djiane J. Effect of PRL on MAPK activation: negative regulatory role of the C-terminal part of the PRL receptor.  Mol Cell Endocrinol. 2000;  159 133-146
    CrossrefPubMedSearch in Google Scholar
  • 8 Yamauchi T, Kaburagi Y, Ueki K, Tsuji Y, Stark G R, Kerr I M, Tsushima T, Akanuma Y, Komuro I, Tobe K, Yasaki Y, Kadowaki T. Growth hormone and prolactin stimulate tyrosine phosphorylation of insulin receptor substrate-1, -2, and -3, their association with p85 phosphatidylinositol 3-kinase (PI3-kinase), and concomitantly PI3-kinase activation via JAK2 kinase.  J Biol Chem. 1998;  273 15 719-15 726
    PubMedSearch in Google Scholar
  • 9 Nielsen J H, Svensson C, Galsgaard E D, Møldrup A, Billestrup N. Beta cell proliferation and growth factors.  J Mol Med. 1999;  77 62-66
    CrossrefPubMedSearch in Google Scholar
  • 10 Nielsen J H, Galsgaard E D, Møldrup A, Friedrichsen B N, Billestrup N, Hansen J A, Lee Y C, Carlsson C. Regulation of β-cell mass by hormones and growth factors.  Diabetes. 2001;  50 [Suppl 1], S25-S29
    PubMedSearch in Google Scholar
  • 11 Folli F, Saad M JA, Backer J M, Kahn C R. Insulin stimulation of phosphatidylinositol 3-kinase activity and association with insulin receptor substrate 1 in liver and muscle of the intact rat.  J Biol Chem. 1992;  267 22 171-22 177
    PubMedSearch in Google Scholar
  • 12 Velloso L A, Carneiro E M, Crepaldi S C, Boschero A C, Saad M JA. Glucose- and insulin-induced phosphorylation of the insulin receptor and its primary substrates IRS-1 and IRS-2 in rat pancreatic islets.  FEBS Lett. 1995;  377 353-357
    CrossrefPubMedSearch in Google Scholar
  • 13 Harbeck M C, Louie D C, Howland J, Wolf B A, Rothenberg P L. Expression of insulin receptor mRNA and insulin receptor substrate 1 in pancreatic islet beta-cells.  Diabetes. 1996;  45 711-717
    PubMedSearch in Google Scholar
  • 14 Saad M JA, Carvalho C RO, Thirone A CP, Velloso L A. Insulin induces tyrosine phosphorylation of JAK2 in insulin-sensitive tissues of intact rat.  J Biol Chem. 1996;  271 22 100-22 104
    PubMedSearch in Google Scholar
  • 15 Trumper K, Trumper A, Trusheim H, Arnold R, Goke B, Horsch D. Integrative mitogenic role of protein kinase B/AKT in β-cells.  Ann N Y Acad Sci. 2000;  921 242-250
    PubMedSearch in Google Scholar
  • 16 Baixeras E, Jeay S, Kelly P A, Postel-Vinay M C. The proliferative and antiapoptotic actions of growth hormone and insulin-like growth factor-1 are mediated through distinct signaling pathways in the Pro-B Ba/F3 cell line.  Endocrinology. 2001;  142 2968-2977
    CrossrefPubMedSearch in Google Scholar
  • 17 Parsons J A, Brelje T C, Sorenson R L. Adaptation of islets of Langerhans to pregnancy: increased islet cell proliferation and insulin secretion correlates with the onset of placental lactogen secretion.  Endocrinology. 1992;  130 1459-1466
    CrossrefPubMedSearch in Google Scholar
  • 18 Sorenson R L, Brelje T C, Roth C. Effects of steroid and lactogenic hormones on islets of Langerhans: a new hypothesis for the role of pregnancy steroids in the adaptation islets to pregnancy.  Endocrinology. 1993;  133 2227-2234
    CrossrefPubMedSearch in Google Scholar
  • 19 Sorenson R L, Brelje T C. Adaptation of islets of Langerhans to pregnancy: β-cells growth, enhanced insulin secretion and the role of lactogenic hormones.  Horm Metab Res. 1997;  29 301-307
    Thieme ConnectPubMedSearch in Google Scholar
  • 20 Green I C, Taylor K W. Effects of pregnancy in the rat on the size and insulin secretory response of the islets of Langerhans.  J Endocr. 1972;  54 317-325
    PubMedSearch in Google Scholar
  • 21 Parsons J A, Bartke A, Sorenson R L. Number and size of islets of Langerhans in pregnant, human growth hormone-expressing transgenic, and pituitary dwarf mice: effect of lactogenic hormones.  Endocrinology. 1995;  136 2013-2021
    CrossrefPubMedSearch in Google Scholar
  • 22 Fleenor D, Petryk A, Driscoll P, Freemark M. Constitutive expression of placental lactogen in pancreatic β cell: effects on cell morphology, growth, and gene expression.  Pediatr Res. 2000;  47 136-142
    PubMedSearch in Google Scholar
  • 23 Vasavada R C, Garcia-Ocaña A, Zawalich W S, Sorenson R L, Dann P, Syed M, Ogren L, Talamantes F, Stewart A F. Targeted expression of placental lactogen in the beta cells of transgenic mice results in beta cell proliferation, islet mass augmentation, and hypoglycemia.  J Biol Chem. 2000;  275 15 399-15 406
    PubMedSearch in Google Scholar
  • 24 Galsgaard E D, Nielsen J H, Moldrup A. Regulation of prolactin receptor (PRLR) gene expression in insulin-producing cells. Prolactin and growth hormone activate one of the rat prlr gene promoters via STAT5a and STAT5b.  J Biol Chem. 1999;  274 18 686-18 692
    PubMedSearch in Google Scholar
  • 25 Boschero A C, Tombaccini D, Atwater I. Effects of glucose on insulin release and 86Rb permeability in cultured neonatal and adult islets.  FEBS Lett. 1988;  236 375-379
    CrossrefPubMedSearch in Google Scholar
  • 26 Boschero A C, Crepaldi S C, Carneiro E M, Delattre E, Atwater I. Prolactin induces maturation of glucose sensing mechanisms in cultured neonatal rat islets.  Endocrinology. 1993;  133 515-520
    CrossrefPubMedSearch in Google Scholar
  • 27 Boschero A C, Tombaccini D, Carneiro E M, Atwater I J. Differences in K+ permeability between cultured adult and neonatal rat islets of Langerhans in response to glucose, tolbutamide, diazoxide and theophylline.  Pancreas. 1993;  8 44-49
    PubMedSearch in Google Scholar
  • 28 Crepaldi S C, Carneiro E M, Boschero A C. Long-term effect of prolactin treatment on glucose-induced insulin secretion in cultured neonatal rat islets.  Horm Metab Res. 1997;  29 220-224
    PubMedSearch in Google Scholar
  • 29 Mendonça A C, Carneiro E M, Bosqueiro J R, Crepaldi-Alves S C, Boschero A C. Development of the insulin secretion mechanism in fetal and neonatal rat pancreatic B-cells: response to glucose, K+, theophylline, and carbamylcholine. Braz.  J Med Biol Res. 1998;  31 841-846
    PubMedSearch in Google Scholar
  • 30 Withers D J, Gutierrez J S, Towery H, Burks D J, Ren J-M, Previs S, Zhang Y, Bernal D, Pons S, Shulman G I, Bonner-Weir S, White M F. Disruption of IRS-2 causes type 2 diabetes in mice.  Nature. 1998;  391 900-904
    CrossrefPubMedSearch in Google Scholar
  • 31 Briaud I, Rouault C, Bailbé D, Portha B, Reach G, Poitout V. Glucose-induced insulin mRNA accumulation is impaired in islets from neonatal streptozotocin-treated rats.  Horm Metab Res. 2000;  32 103-106
    PubMedSearch in Google Scholar
  • 32 Laemmli U K. Cleavage of a structural proteins during the assembly of the head of bacteriophage T.  Nature. 1970;  227 680-685
    PubMedSearch in Google Scholar
  • 33 Yu Z-W, Eriksson J W. The upregulating effect of insulin and vanadate on cell surface insulin receptors in rat adipocytes is modulated by glucose and energy availability.  Horm Metab Res. 2000;  32 310-315
    PubMedSearch in Google Scholar
  • 34 Berlanga J J, Gualillo O, Buteau H, Applanat M, Kelly P A, Edery M. Prolactin actives tyrosyl phosphorylation of insulin receptor substrate1 and phosphatidylinositol-3-OH kinase.  J Biol Chem. 1997;  272 2050-2052
    CrossrefPubMedSearch in Google Scholar
  • 35 Ptasznik A, Beattie G M, Mally M I, Cirulli V, Lopez A, Hayek A. Phosphatidylinositol 3-kinase is a negative regulator of cellular differentiation.  J Cell Biol. 1997;  137 1127-1136
    CrossrefPubMedSearch in Google Scholar
  • 36 Levy-Toledano R, Blaettler D H, LaRochelle W J, Taylor S I. Insulin-induced activation of phosphatidylinositol (PI) 3-kinase.  J Biol Chem. 1995;  270 30 018-30 022
    PubMedSearch in Google Scholar
  • 37 Velloso L A, Folli F, Sun X J, White M F, Saad M JA, Kahn C R. Cross-talk between the insulin and angiotensin signaling systems.  Proc Natl Acad Sci USA. 1996;  93 12 490-12 495
    PubMedSearch in Google Scholar
  • 38 Fasshauer M, Klein J, Ueki K, Kriauciunas K M, Benito M, White M F, Kahn C R. Essential role of insulin receptor substrate-2 in insulin stimulation of Glut 4 translocation and glucose uptake in brown adipocytes.  J Biol Chem. 2000;  275 25 494-25 501
    PubMedSearch in Google Scholar
  • 39 Mandrup-Poulsen T. Beta-cell apoptosis: stimuli and signaling.  Diabetes. 2001;  50 [Suppl 1] S58-S63
    CrossrefPubMedSearch in Google Scholar
  • 40 Nunoi K, Yasuda K, Tanaka H, Kubota A, Okamoto Y, Adachi T, Shihara N, Uno M, Xu L M, Kagimoto S, Seino Y, Yamada Y, Tsuda K. Wortmannin, a PI 3-kinase inhibitor: promoting effect on insulin secretion from pancreatic beta cells through cAMP-dependent pathway.  Biochem Biophys Res Commun. 2000;  270 798-805
    CrossrefPubMedSearch in Google Scholar
  • 41 Aspinwall C A, Qian W-J, Roper M G, Kulkarni R N, Kahn C R, Kennedy R T. Roles of insulin receptor substrate-1, phosphatidylinositol 3-kinase, and release of intracellular Ca2+ stores in insulin-stimulated insulin secretion in β-cells.  J Biol Chem. 2000;  275 22 331-22 341
    PubMedSearch in Google Scholar
  • 42 Da Silva Xavier G, Varadi A, Ainscow E K, Rutter G A. Regulation of gene expression by glucose in pancreatic beta-cells (MIN 6) via insulin secretion and activation of phosphatidylinositol 3-kinase.  J Biol Chem. 2000;  275 36 269-36 277
    PubMedSearch in Google Scholar
  • 43 Aikin R, Rosenberg L, Maysinger D. Phosphatidylinositol 3-kinase signaling to AKT mediates survival in isolated canine islets of Langerhans.  Biochem Biophys Res Commun. 2000;  277 455-461
    CrossrefPubMedSearch in Google Scholar
  • 44 Friedrichsen B N, Galsgaard E D, Nielsen J H, Møldrup A. Growth hormone- and prolactin- induced proliferation of insulinoma cells, INS-1, depends on activation of STAT5 (signal transducer and activator of transcription 5).  Mol Endocrinol. 2001;  15 136-148
    CrossrefPubMedSearch in Google Scholar
  • 45 Buckley A R, Buckley D J. Prolactin regulation of apoptosis-associated gene expression in T cells.  Ann N Y Acad Sci. 2000;  917 522-533
    PubMedSearch in Google Scholar

Prof. A. C. Boschero

Departamento de Fisiologia e Biofísica · Instituto de Biologia · CP 6109 · Universidade Estadual de Campinas (UNICAMP)

Campinas 13083-970 · SP · Brasil

Phone: 55 19 3788 6202

Fax: 55 19 3289 3124

Email: boschero@unicamp.br