Endocrinology, Vol 131, 1069-1074, Copyright © 1992 by Endocrine Society

ARTICLES

Pituitary adenylate cyclase-activating polypeptide stimulates calcium mobilization in amphibian pituitary cells

F Gracia-Navarro, M Lamacz, MC Tonon and H Vaudry
Department of Cell Biology, University of Cordoba, Spain.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a 38- amino acid peptide of the glucagon-secretin-vasoactive intestinal polypeptide superfamily. Although PACAP is a potent stimulator of adenylate cyclase activity in the adenohypophysis, the precise target cells for PACAP in the anterior pituitary remain unknown. The aim of the present study was to investigate whether PACAP could stimulate calcium mobilization in individual cells of the pituitary and to determine the type of cells that responded to PACAP. Enzymatically dispersed frog distal pituitary cells were plated on photoetched coverslips and cultured for 3-7 days. The cells were loaded with the fluorescent calcium indicator indo-1, and changes in intracellular calcium concentrations ([Ca2+]i) were monitored using dual wavelength microfluorimetry. The individual cells were localized with the aid of the alpha/numeric grid of the coverslips and identified retrospectively by immunofluorescence. Approximately 45% of GH and PRL cells and 25% of ACTH and TSH cells responded to PACAP (10(-5) M) ejection by an elevation of [Ca2+]i. Only 16% of gonadotropes were stimulated by PACAP. The time course of [Ca2+]i variations showed three different patterns: transient spikes, sustained stimulations, and oscillatory responses. In addition, heterogenous responses were observed within each cell type. These data provide evidence for the involvement of calcium mobilization in the mechanism of action of PACAP on pituitary cells. The results also indicate that in frogs, PACAP may stimulate the secretory activity of GH and PRL cells and, to a lesser extent, ACTH, TSH, and gonadotrope cells.

This article has been cited by other articles:

				J. M. Lugo, A. Rodriguez, Y. Helguera, R. Morales, O. Gonzalez, J. Acosta, V. Besada, A. Sanchez, and M. P. Estrada Recombinant novel pituitary adenylate cyclase-activating polypeptide from African catfish (Clarias gariepinus) authenticates its biological function as a growth-promoting factor in low vertebrates J. Endocrinol., June 1, 2008; 197(3): 583 - 597. [Abstract] [Full Text] [PDF]

				R. OKADA, K. YAMAMOTO, Y. ITO, N. CHARTREL, J. LEPRINCE, A. FOURNIER, H. VAUDRY, and S. KIKUYAMA Effects of Pituitary Adenylate Cyclase-Activating Polypeptide, Vasoactive Intestinal Polypeptide, and Somatostatin on the Release of Thyrotropin from the Bullfrog Pituitary Ann. N.Y. Acad. Sci., July 1, 2006; 1070(1): 474 - 480. [Abstract] [Full Text] [PDF]

				D. Alexandre, H. Vaudry, L. Grumolato, V. Turquier, A. Fournier, S. Jegou, and Y. Anouar Novel Splice Variants of Type I Pituitary Adenylate Cyclase-Activating Polypeptide Receptor in Frog Exhibit Altered Adenylate Cyclase Stimulation and Differential Relative Abundance Endocrinology, July 1, 2002; 143(7): 2680 - 2692. [Abstract] [Full Text] [PDF]

				Z. Hu, V. Lelievre, J. Tam, J. W. Cheng, G. Fuenzalida, X. Zhou, and J. A. Waschek Molecular Cloning of Growth Hormone-Releasing Hormone/Pituitary Adenylyl Cyclase-Activating Polypeptide in the Frog Xenopus laevis: Brain Distribution and Regulation after Castration Endocrinology, September 1, 2000; 141(9): 3366 - 3376. [Abstract] [Full Text] [PDF]

				K. Furuya, R. J. Milchak, K. M. Schegg, J. Zhang, S. S. Tobe, G. M. Coast, and D. A. Schooley Cockroach diuretic hormones: Characterization of a calcitonin-like peptide in insects PNAS, June 6, 2000; 97(12): 6469 - 6474. [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]

				Z. Hu, V. Lelievre, A. Chao, X. Zhou, and J. A. Waschek Characterization and Messenger Ribonucleic Acid Distribution of a Cloned Pituitary Adenylate Cyclase-Activating Polypeptide Type I Receptor in the Frog Xenopus laevis Brain Endocrinology, February 1, 2000; 141(2): 657 - 665. [Abstract] [Full Text] [PDF]

				J. L. González de Aguilar, M. M. Malagón, R. M. Vázquez-Martínez, A. J. Martínez-Fuentes, M. C. Tonon, H. Vaudry, and F. Gracia-Navarro Differential Effects of Dopamine on Two Frog Melanotrope Cell Subpopulations Endocrinology, January 1, 1999; 140(1): 159 - 164. [Abstract] [Full Text]

				A. J. Martinez-Fuentes, J. P. Castano, F. Gracia-Navarro, and M. M. Malagon Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) 38 and PACAP27 Activate Common and Distinct Intracellular Signaling Pathways to Stimulate Growth Hormone Secretion from Porcine Somatotropes Endocrinology, December 1, 1998; 139(12): 5116 - 5124. [Abstract] [Full Text] [PDF]

				M. Montero, L. Yon, K. Rousseau, A. Arimura, A. Fournier, S. Dufour, and H. Vaudry Distribution, Characterization, and Growth Hormone-Releasing Activity of Pituitary Adenylate Cyclase-Activating Polypeptide in the European Eel, Anguilla anguilla Endocrinology, October 1, 1998; 139(10): 4300 - 4310. [Abstract] [Full Text] [PDF]

				J. L. Gonzalez de Aguilar, M. M. Malagon, R. M. Vazquez-Martinez, I. Lihrmann, M.-C. Tonon, H. Vaudry, and F. Gracia-Navarro Two Frog Melanotrope Cell Subpopulations Exhibiting Distinct Biochemical and Physiological Patterns in Basal Conditions and under Thyrotropin-Releasing Hormone Stimulation Endocrinology, March 1, 1997; 138(3): 970 - 977. [Abstract] [Full Text] [PDF]