Protein kinase C activation mediates acidosis down-regulation of intestinal arginine absorption in proliferating rat crypt cells

• Published in: The Journal of surgical research 2004-10, Vol.121 (2), p.275-275
• Main Authors: Choudry, H.A., Souba, W.W., Meng, Q., Vary, T.C., Karinch, A.M., Lin, C., Pan, M.
• Format: Article
• Language: English
• ISSN: 0022-4804; 1095-8673
• DOI: 10.1016/j.jss.2004.07.031

Introduction. The small intestinal undifferentiated crypt cells and differentiated villous cells serve different physiological functions in response to various stimuli. L-Arginine is the exclusive precursor for nitric oxide (NO) biosynthesis and an important nutrient for intestinal integrity during stress states. The purpose of this in vitro study was to investigate the poorly understood intracellular signaling pathways involved in the acidosis regulation of intestinal membrane arginine absorption in the undifferentiated rat intestinal crypt IEC-6 cells. Methods. IEC-6 cells were grown to subconfluence and incubated in growth media of various pHs (pH 6.6 to pH 7.4, adjusted with 1 M HCl and/or NaHCO 3), ±PKC inhibitor Chelerythrine Cl (CHEL, 0–6.6 μM), Phosphatidylinositide-3 kinase (PI-3 kinase) inhibitors wortmannin (0–10 μM), and LY 294004 (LY, 0–10 μM). 3H-arginine (5 μm) transport activity, arginine transporter MCAT1 mRNA levels, cellular protein kinase C (PKC) levels were measured. Data are means ± SD and analyzed by ANOVA with P < 0.05. Results. Desired extracellular pH (pH 6.6 to pH 7.4) was achieved in 6 h and remained stable. Chronic acidosis (pH 6.6,