Different phlorizin binding properties to porcine mucosa of the jejunum and ileum in relation to SGLT1 activity

作者：Herrmann J^*; Moeller N; Lange P; Breves G

来源：Journal of Animal Science, 2016, 94(suppl_3): 238-242.

DOI：10.2527/jas2015-9702

• alpha-methyl-D-glucopyranoside
• intestinal transport
• phlorizin
• pigs
• SGLT1
• small intestines

The capacity for electrogenic glucose transport is higher in the porcine ileum compared with the jejunum, independent from the abundance of Na+/glucose-linked cotransporter 1 (SGLT1) in the apical membrane. However, it is unknown whether SGLT1 is only associated with or functionally integrated into the membrane when it is detected by immunoblotting. Phlorizin is a potent SGLT1 inhibitor and can be used as an indicator for active SGLT1 protein, which was the aim of this study. In Ussing chambers, the electrogenic response of SGLT1-mediated transport in porcine jejunal and ileal mucosa was induced with alpha-methyl-D-glucopyranoside (AMG) and was terminated by phlorizin administration. Additionally, brush-border membrane vesicles (BBMV) were prepared and incubated with [H-3]-phlorizin to estimate membrane-integrated SGLT1. Ileal increases in short-circuit conditions (I-sc) after AMG were greater compared with the jejunum (P < 0.01). Subsequent phlorizin treatment caused similar I-sc decreases close to basal levels in the intestinal segments. Na+-dependent [H-3]-phlorizin binding to BBMV was similar in both segments. In contrast to the ileum, jejunal BBMV had an unspecific binding capacity similar to Na+-dependent binding. In consequence, Na+-specific phlorizin binding was greater in the ileum (P < 0.01). Immunoblotting with BBMV revealed similar total apical SGLT1 abundance in both intestinal segments. Phlorizin treatment as indicator for active SGLT1 molecules approved similar apical transporter abundance in porcine jejunum and ileum based on Na+-dependent phlorizin binding but also revealed unexpected Na+-independent phlorizin binding to jejunal BBMV.

• 出版日期2016-9