Volume-sensitive amino acid efflux from a pancreatic β-cell line

• Published in: Molecular and cellular endocrinology Vol. 162; no. 1; pp. 201 - 208
• Main Authors: Grant, A.C.G., Thomson, J., Zammit, V.A., Shennan, D.B.
• Format: Journal Article
• Language: English
• Published: Elsevier Ireland Ltd 25-04-2000
• Subjects: Animo acid efflux; Cell swelling; Hyposmotic shock; Pancreatic β cell line; Pancreatic β cell line; Hyposmotic shock; Animo acid efflux; Cell swelling
• ISSN: 0303-7207; 1872-8057
• DOI: 10.1016/S0303-7207(99)00260-9

Cell swelling, induced by a hyposmotic shock, increased the fractional release of taurine from INS-1 cells. Volume-sensitive taurine release was (a) dependent upon the extent of cell swelling; (b) fully reversible; and (c) temperature dependent. Volume-sensitive taurine efflux was independent from the
trans-membrane Na
+-gradient. DIDS markedly inhibited volume-activated taurine efflux but not basal taurine release suggesting that the volume-sensitive pathway is quiescent under isosmotic conditions. Volume-activated taurine release inactivated in the continued presence of a hyposmotic shock. Cell-swelling also increased the fractional release of
d-aspartate from INS-1 cells. Volume-activated
d-aspartate efflux was inhibited by DIDS, albeit to a lesser extent than volume-sensitive taurine release. It is predicted that volume-sensitive amino acid efflux acts in parallel with other volume-activated transport mechanisms to regulate the volume of insulin-secreting cells.