Tohoku J. Exp. Med., 2002, 198 (3)

Role of Mitochondrial NADH Shuttle System in Acute Amylase Secretion
by Acetylcholine from Mouse Pancreatic Acinar Cells

KYOKO NAKANO, TERUKO TAKEO, TATSUSUKE SATO, SECHIKO SUGA,¹ KAZUHIRO ETO,²
TAKASHI KADOWAKI² and MAKOTO WAKUI¹

Department of Medical Technology, Hirosaki University School of Health Sciences, Hirosaki 036-8564, ¹Department of Physiology, Hirosaki University School of Medicine, Hirosaki 036-8562, and ²Department of Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655

Using the mice that lack mitochondrial glycerol-3-phosphate dehydrogenase (mGPDH), a rate limiting enzyme of the glycerol-phosphate NADH shuttle, we investigated the role of the NADH shuttle system in amylase secretion in response to acetylcholine (ACh) in pancreatic acinar cells. The pancreatic acinar cells of mGPDH-deficient mice were not different in histology and immunohistochemistry from those of wild-type mice. In both types of pancreatic acinar cells from wild-type and mGPDH-deficient mice, ACh similarly potentiated amylase secretion, measured in 30 minutes after the ACh stimulation. A 30 minutes pre-treatment of wild-type cells with aminooxyacetate (AOA), an inhibitor of aspartate aminotransferases of the malate-aspartate NADH shuttle, did not change the rate of ACh-induced amylase secretion, measured in the following 30 minutes. In also mGPDH-deficient cells treated with AOA, thus in this situation all mitochondrial NADH shuttles being dysfunctioning, ACh induced amylase release in a similar amount to that in AOA-untreated cells. The basal levels of intracellular Ca²⁺ concentration ([Ca²⁺]_i), the ACh-stimulated levels of [Ca²⁺]_i and Ca²⁺ oscillation patterns in response to ACh were similar in wild-type and mGPDH-deficient cells, and the AOA-treatment did not affect these [Ca²⁺]_i responses. The levels of intracellular concentration of ATP before and during stimulation with ACh were similar in wild-type and mGPDH-defficient cells. In only AOA-treated mGPDH-deficient cells, the level of ATP decreased after the ACh stimulation. These results suggest that acute response of amylase secretion to ACh from mouse pancreatic acinar cells does not require simultaneous functioning of the mitochondrial NADH shuttle system, although the supply of intracellular ATP decreases during the ACh stimulation.

Keywords —— pancreas; acetylcholine; amylase secretion; NADH shuttle system

© 2002 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2002, 198, 151-162

Address for reprints: Kyoko Nakano, M.D., Department of Medical Technology, Hirosaki University School of Health Sciences, 66-1 Honcho, Hirosaki 036-8564, Japan.

e-mail: n1220@cc.hirosaki-u.ac.jp