The possible involvement of pancreatic polypeptide in the paracrine regulation of human and rat adrenal cortex.
Pancreatic polypeptide (PP) is a member of a family of 36-amino acid brain-gut peptides, including neuropeptide Y (NPY) and polypeptide YY (PYY) and acting through many subtypes of Y receptors belonging to the superfamily of the G protein-coupled receptors. PP was found to increase both glucocorticoid and cyclic-AMP production by dispersed rat and human adrenocortical cells in a concentration-dependent manner. Minimal and maximal effective concentrations were 10(-10) and 10(-8) M, respectively. The glucocorticoid secretagogue effect of 10(-8) M PP was blocked by the protein kinase A (PKA) unhibitor H-89, but not by the ACTH-receptor antagonist corticotropin-inhibiting peptide (CIP) Autoradiography showed the presence of [125I]PP binding sites in the inner zones of rat and human adrenal cortex, which were not displaced by NPY, PYY, ACTH or CIP. Sizable amounts of PP-immunoreactivity were detected in the medulla of both rat and human adrenals (about 50-100 fmol/mg); this content may give rise, upon submaximal stimulation of PP release, to local intraadrenal concentrations of about 10(-8)/10(-7) M. Collectively, these findings allow us to draw the following conclusions: (i) PP stimulates glucocorticoid secretion, acting through specific receptors coupled with the adenylate cyclase/PKA-dependent signaling pathway; and (ii) PP could be included in that group of regulatory peptides, contained in adrenal medulla, which are able to control the secretory function of the cortex acting in a paracrine manner.
Nussdorfer
G G
GG
Department of Anatomy, University of Padua, Italy.
Mazzocchi
G
G
Malendowicz
L K
LK
D000302:Adrenal Cortex / Q000166:cytology / Q000502:physiology*; D000313:Adrenal Medulla / Q000378:metabolism; D000818:Animals; D001345:Autoradiography; D001665:Binding Sites / Q000502:physiology; D002478:Cells, Cultured; D003345:Corticosterone / Q000096:biosynthesis; D006801:Humans; D006854:Hydrocortisone / Q000096:biosynthesis; D008297:Male; D009994:Osmolar Concentration; D010191:Pancreatic Polypeptide / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D019899:Paracrine Communication / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D014018:Tissue Distribution
D010191:Pancreatic Polypeptide; D003345:Corticosterone; D006854:Hydrocortisone