This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Martínez-Fuentes, A. J. Articles by Malagón, M. M. Search for Related Content PubMed PubMed Citation Articles by Martínez-Fuentes, A. J. Articles by Malagón, M. M.

Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) 38 and PACAP27 Activate Common and Distinct Intracellular Signaling Pathways to Stimulate Growth Hormone Secretion from Porcine Somatotropes¹

Department of Cell Biology, University of Córdoba, 14004-Córdoba, Spain

Address all correspondence and requests for reprints to: Dr. F. Gracia-Navarro, Department of Cell Biology. Faculty of Sciences, University of Córdoba, Avinguda San Alberto Magno, s/n, 14004-Cordoba, Spain. E-mail: bc1grnaf{at}uco.es

We have recently shown that the two bioactive forms of pituitary adenylate cyclase-activating polypeptide, PACAP38 and PACAP27, stimulate GH release and GH messenger RNA (mRNA) accumulation in cultured porcine pituitary cells. However, dose- and time-related differences in the response to both peptides suggested that the signaling mechanisms activated by PACAP38 and PACAP27 in this cell type could differ. To test this hypothesis, we have evaluated hormone release and GH mRNA content after PACAP treatment in combination with selective activators and inhibitors of the adenylate cyclase/cAMP/protein kinase A and the phospholipase C/inositol phosphate (IP)/protein kinase C pathways, and with blockers of intra- and extracellular Ca²⁺. Our results show that activation of the adenylate cyclase/cAMP/protein kinase A system, and extracellular Ca²⁺ entry through L-type Ca²⁺-channels are prevailing and requisite signals for the transduction of the stimulatory effects of both PACAP38 and PACAP27 on GH release and transcription in porcine somatotropes. However, phospholipase C and intracellular Ca²⁺ also contribute, although partially, to PACAP38-induced, but not to PACAP27-induced increase in porcine GH secretion and mRNA levels. These findings demonstrate that in normal somatotropes, PACAP38 can activate multiple transduction pathways that differ from those employed by PACAP27. Moreover, these differences could account for the previously described divergences in the actions of either peptide in porcine somatotropes.

This article has been cited by other articles:

				A. O. L. Wong, W. Li, C. Y. Leung, L. Huo, and H. Zhou Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) as a Growth Hormone (GH)-Releasing Factor in Grass Carp. I. Functional Coupling of Cyclic Adenosine 3',5'-Monophosphate and Ca2+/Calmodulin-Dependent Signaling Pathways in PACAP-Induced GH Secretion and GH Gene Expression in Grass Carp Pituitary Cells Endocrinology, December 1, 2005; 146(12): 5407 - 5424. [Abstract] [Full Text] [PDF]

				C. Klausen, T. Tsuchiya, J. P. Chang, and H. R. Habibi PKC and ERK are differentially involved in gonadotropin-releasing hormone-induced growth hormone gene expression in the goldfish pituitary Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2005; 289(6): R1625 - R1633. [Abstract] [Full Text] [PDF]

				A. Bhattacharya, S. S. Lakhman, and S. Singh Modulation of L-type Calcium Channels in Drosophila via a Pituitary Adenylyl Cyclase-activating Polypeptide (PACAP)-mediated Pathway J. Biol. Chem., September 3, 2004; 279(36): 37291 - 37297. [Abstract] [Full Text] [PDF]

				L. L. Anderson, S. Jeftinija, and C. G. Scanes Growth Hormone Secretion: Molecular and Cellular Mechanisms and In Vivo Approaches Experimental Biology and Medicine, April 1, 2004; 229(4): 291 - 302. [Abstract] [Full Text] [PDF]

				M. M. Malagon, R. M. Luque, E. Ruiz-Guerrero, F. Rodriguez-Pacheco, S. Garcia-Navarro, F. F. Casanueva, F. Gracia-Navarro, and J. P. Castano Intracellular Signaling Mechanisms Mediating Ghrelin-Stimulated Growth Hormone Release in Somatotropes Endocrinology, December 1, 2003; 144(12): 5372 - 5380. [Abstract] [Full Text] [PDF]

				J. L. Ramirez, F. Gracia-Navarro, S. Garcia-Navarro, R. Torronteras, M. M. Malagon, and J. P. Castano Somatostatin Stimulates GH Secretion in Two Porcine Somatotrope Subpopulations through a cAMP-Dependent Pathway Endocrinology, March 1, 2002; 143(3): 889 - 897. [Abstract] [Full Text] [PDF]

				D. Vaudry, B. J. Gonzalez, M. Basille, L. Yon, A. Fournier, and H. Vaudry Pituitary Adenylate Cyclase-Activating Polypeptide and Its Receptors: From Structure to Functions Pharmacol. Rev., June 1, 2000; 52(2): 269 - 324. [Abstract] [Full Text] [PDF]