title: Cell swelling-induced peptide hormone secretion.
abstract: Cell swelling induces peptide exocytosis using unique signaling pathway. Hyposmotic-induced secretion in normal cells is not mediated by specific receptors, is independent from extra and intracellular Ca(2+), sodium and potassium channels activity, prostaglandins, leukotriens, does not involve cytoskeleton, cAMP generation, phospholipase A(2), G proteins, protein kinase C. It is promoted by swelling of the secretory vesicles. Resistance to endogenous inhibitors is frequent attribute of this type of secretion. Swelling-induced secretion involves also secretory vesicles not involved in conventional stimulation. Hyposmosis-induced insulin secretion is more sensitive to high cellular cholesterol than conventional one suggesting substantial difference between mechanisms. Participation of sequential exocytosis as dominating mechanism in swelling-induced exocytosis is hypothesized. Signaling and response in tumor cells often differs from native cells and varies markedly between cell lines. Pathogenetic implications: cell swelling could be involved in alcohol induced hypoglycemia in diabetic patients and release of peptides from pituitary and neurons. Swelling-induced products could be mediators of ischemic preconditioning involved also in protection of diabetic heart. Swelling-induced exocytosis is an ancient mechanism generally present in cells; in cells engaged in water and salt regulation is covered by specific response mediated by specific signaling. Disturbance of specific response leads to swelling-induced - inappropriate secretion of antidiuretic hormone - SIADH.
authors.affiliation: Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia. Vladimir.strbak@savba.sk
authors.forename: Vladimír
authors.initials: V
authors.lastname: Strbák
mesh_terms: D048429:Cell Size; D005089:Exocytosis; D006801:Humans; D007473:Ion Channels / Q000378:metabolism; D007511:Ischemia / Q000503:physiopathology; D036361:Peptide Hormones / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D007473:Ion Channels; D036361:Peptide Hormones