Gasser, Kenneth W.
B.S. (Bachelor of Science)
Department of Biological Sciences
Pancreatic secretory granules contain electrolyte transport pathways for Cl⁻ and K⁺ that may contribute to exocyto- tic membrane fusion or net fluid secretion following membrane fusion. Recently the granule K⁺ transport pathway was shown to exhibit characteristics of the ATP-sensitive K⁺ channels which include inhibition by ATP. K⁺ transport by the zymogen granule membrane was measured indirectly following K+ dependent osmotic swelling and ionophore-induced lysis of the granule while incubated in KC1 and sucrose solutions, pH 7.0, at 37°C. This lysis rate was K⁺ dependent and ATP inhibited. The results also show that this granule K⁺ transport pathway can be activated by cAMP- dependent protein kinase phosphorylation. ATP reduced the K⁺ dependent rate in a dose dependent manner. Subsequent incubation of apical plasma membranes with 15 units/ml of the catalytic subunit of protein kinase A restored K⁺ transport in fusion experiments. Although protein kinase C induced K⁺ transport was not elevated over control levels, the results of protein kinase A stimulated K⁺ transport support the assertion of ATP-sensitive K⁺ transport by secretory granules. This suggests a mechanism for the regulation of secretory granules consistent with the known signaling mechanisms controlling stimulus-secretion coupling in pancreatic acinar cells.
Lindley, Kimberly A., "ATP-sensitive K? transport in rat pancreatic zymogen granule membranes and activation by protein kinase A." (1996). Honors Capstones. 199.
29 unnumbered pages
Northern Illinois University
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