Abstract
Abstract: :
Purpose: To characterize the mode of glucose transport mechanism in the bovine ciliary body epithelium (CBE). Methods: Fresh bovine CBE was isolated and mounted with a modified Ussing chamber. The electrical parameters at 35-37°C were recorded using the Dual Voltage Clamp-1000 (World Precision Instruments, Sarasota, FL). The L-[3H]-glucose (LG) and 3-O-methyl-D-[14C]-glucose (MDG) fluxes across the CBE were studied. Effects with different inhibitors, phloretin (0.1mM), cytochalasin-B (0.01mM) and ouabain (0.1mM), on glucose flux were also investigated. Results: There was no significant net glucose (both LG and MDG) flux across the bovine CBE (p≷0.05, n=10). The LG flux was 26±2 nEqh-1cm-2 both from stroma to aqueous sides (SèA) and aqueous to stroma sides (AèS). MDG fluxes were 196±15 nEqh-1cm-2 (SèA) and 190±15 nEqh-1cm-2 (AèS). Bilateral addition of inhibitors, phloretin (0.1mM) and cytochalasin-B (0.01mM), significantly reduced the MDG (but not LG) flux by 43.8% (p<0.001, n=11) and 80.3% (p<0.001, n=9) respectively. No significant reduction was found in glucose flux after the addition of ouabain (0.1mM). Conclusion: No active glucose secretion was found for both LG and MDG in this study. Facilitative glucose transport is the major mode of glucose transport mechanism in the bovine CBE. Supported by The Hong Kong Polytechnic University Research Grant GW079.
Keywords: 348 ciliary body • 438 inflow/ciliary body