A New Role for Aquaporin 7 in Insulin Secretion

Cellular Physiology and Biochemistry

关键词: Cell swelling;    AQP7;    Insulin-producing β-cells;    Insulin secretion;   

DOI  :  10.1159/000337588

学科分类：分子生物学，细胞生物学和基因

来源: S Karger AG

【 摘 要 】

Bacgrouns/Aims Several insulinotropic agents were recently reported to cause β-cell swelling. The possible participation of AQP7 to water transport was investigated in AQP7^{+/ +} or AQP7^-/- mice. Methods Aquaporin expression, insulin secretion, cell swelling and electrical activity were investigated in pancreatic islets. Results RT-PCR revealed the expression of AQP5 and AQP8 mRNA. Double immunofluorescent labeling indicated their presence in β-cells. Whilst basal insulin release from isolated pancreatic islets incubated at 2.8 mM D-glucose did not differ between AQP7^{+/ +} or AQP7^-/- mice, the secretion of insulin evoked by the omission of 50 mM NaCl, the substitution of 50 mM NaCl by 100 mM glycerol or a rise in D-glucose concentration to 8.3 mM and 16.7 mM was severely impaired in the islets from AQP7^-/- mice. Yet, exposure of β-cells to either the hypotonic medium or a rise in D-glucose concentration caused a similar degree of swelling and comparable pattern of electrical activity in cells from AQP7^{+/ +} and AQP7^-/- mice. Both the cell swelling and change in membrane potential were only impaired in AQP7^-/- cells when exposed to 50 mM glycerol. Conclusion It is proposed, therefore, that AQP7 may, directly or indirectly, play a role at a distal site in the exocytotic pathway.

【 授权许可】

CC BY-NC-ND