HOME HELP CONTACT US SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Anhê, G. F Articles by Bordin, S. Search for Related Content PubMed PubMed Citation Articles by Anhê, G. F Articles by Bordin, S.

Laboratory of Molecular Biology, Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo (USP), Lineu Prestes Avenue 1524, São Paulo 05508-900, Brazil
¹ Laboratory of Endocrine Pancreas Physiology, Department of Biological Sciences, São Paulo State University (UNESP), Bauru, SP, Brazil
² Laboratory of Endocrine Pancreas and Metabolism, Department of Physiology and Biophysics, Institute of Biology, State University of Campinas (UNICAMP), Campinas, SP, Brazil

(Correspondence should be addressed to S Bordin; Email: sbordin{at}icb.usp.br)

During pregnancy, the maternal endocrine pancreas undergoes, as a consequence of placental lactogens and prolactin (PRL) action, functional changes that are characterized by increased glucose-induced insulin secretion. After delivery, the maternal endocrine pancreas rapidly returns to non-pregnant state, which is mainly attributed to the increased serum levels of glucocorticoids (GCs). Although GCs are known to decrease insulin secretion and counteract PRL action, the mechanisms for these effects are poorly understood. We have previously demonstrated that signal transducer and activator of transcription 3 (STAT3) is increased in islets treated with PRL. In the present study, we show that STAT3 expression and serine phosphorylation are increased in pancreatic islets at the end of pregnancy (P19). STAT3 serine phosphorylation rapidly returned to basal levels 3 days after delivery (L3). The expression of the sarcoendoplasmic reticulum Ca²⁺-ATPase 2 (SERCA2), a crucial protein involved in the regulation of calcium handling in ß-cells, was also increased in P19, returning to basal levels at L3. PRL increased SERCA2 and STAT3 expressions and STAT3 serine phosphorylation in RINm5F cells. The upregulation of SERCA2 by PRL was abolished after STAT3 knockdown. Moreover, PRL-induced STAT3 serine phosphorylation and SERCA2 expression were inhibited by dexamethasone (DEX). Insulin secretion from islets of P19 rats pre-incubated with thapsigargin and L3 rats showed a dramatic suppression of first phase of insulin release. The present results indicate that PRL regulates SERCA2 expression by a STAT3-dependent mechanism. PRL effect is counteracted by DEX and might contribute to the adaptation of maternal endocrine pancreas during the peripartum period.

This article has been cited by other articles:

				E. C. Vanzela, R. A. Ribeiro, C. A. M. de Oliveira, F. B. Rodrigues, M. L. Bonfleur, E. M. Carneiro, K. L. A. Souza, and A. C. Boschero Pregnancy restores insulin secretion from pancreatic islets in cafeteria diet-induced obese rats Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2010; 298(2): R320 - R328. [Abstract] [Full Text] [PDF]