| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Articles |
Parathyroid hormone (PTH)-related protein (PTHrP) is present in the pancreatic islet. Recent data in transgenic mice suggest that PTHrP might modulate islet mass and insulin secretion. In the present study, we assessed the effect of the N-terminal PTH-like region of PTHrP on DNA synthesis in isolated rat islets. PTHrP (1-34), between 1 pM and 10 nM, for 48 h stimulated []thymidine incorporation into rat islets. This effect was maximally induced, about 2.5-fold over control, by 10 pM of this peptide, decreasing thereafter. In contrast, PTHrP (38-64) amide or PTHrP (107-139) were ineffective in increasing DNA synthesis in islets. Using reverse transcription followed by PCR, we confirmed that rat islets express PTHrP and the type I PTH/PTHrP receptor. Addition of a neutralizing anti-PTHrP antibody to the incubation medium of proliferating islets decreased islet DNA synthesis by 30%. The effect of a submaximal dose (30 pM) of PTHrP (1-34) on DNA synthesis in rat islets was abolished by 25 nM bisindolylmaleimide I, a protein kinase C (PKC) inhibitor, but not by 25 microM adenosine 3',5'-cyclic monophosphorothioate, Rp-isomer, a protein kinase A inhibitor. Moreover, 100 nM phorbol-12-myristate-13-acetate for 48 h also increased DNA synthesis 2-fold over controls in islets. PTHrP (1-34), at 100 nM, in contrast to 50 microM forskolin or 10 mM NaF, failed to affect adenylate cyclase activity in islet membranes. PTHrP, at 30 pM, was also found to increase 2-fold insulin released into the islet-conditioned medium within 24-48 h. Our results suggest that PTHrP is a modulator of pancreatic islet growth and/or function by a PKC-mediated mechanism.
This article has been cited by other articles:
|
|
 |
|
  J. L. Beith, E. U. Alejandro, and J. D. Johnson Insulin Stimulates Primary {beta}-Cell Proliferation via Raf-1 Kinase Endocrinology, May 1, 2008; 149(5): 2251 - 2260. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. C. Vasavada, L. Wang, Y. Fujinaka, K. K. Takane, T. C. Rosa, J. M.D. Mellado-Gil, P. A. Friedman, and A. Garcia-Ocana Protein Kinase C-{zeta} Activation Markedly Enhances {beta}-Cell Proliferation: An Essential Role in Growth Factor Mediated {beta}-Cell Mitogenesis Diabetes, November 1, 2007; 56(11): 2732 - 2743. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. S. Narang and R. I. Mahato Biological and biomaterial approaches for improved islet transplantation. Pharmacol. Rev., June 1, 2006; 58(2): 194 - 243. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Fujinaka, D. Sipula, A. Garcia-Ocana, and R. C. Vasavada Characterization of Mice Doubly Transgenic for Parathyroid Hormone-Related Protein and Murine Placental Lactogen: A Novel Role for Placental Lactogen in Pancreatic {beta}-Cell Survival Diabetes, December 1, 2004; 53(12): 3120 - 3130. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Cebrian, A. Garcia-Ocana, K. K. Takane, D. Sipula, A. F. Stewart, and R. C. Vasavada Overexpression of Parathyroid Hormone-Related Protein Inhibits Pancreatic {beta}-Cell Death In Vivo and In Vitro Diabetes, October 1, 2002; 51(10): 3003 - 3013. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. W.J. Janssen, J. G.J. Hoenderop, A. R.M.M. Hermus, F. C.G.J. Sweep, G. J.M. Martens, and R. J.M. Bindels Expression of the Novel Epithelial Ca2+ Channel ECaC1 in Rat Pancreatic Islets J. Histochem. Cytochem., June 1, 2002; 50(6): 789 - 798. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
