Wakisaka M, Yoshinari M, Yamamoto M, Nakamura S, Asano T, Himeno T, Ichikawa K, Doi Y, Fujishima M
Second Department of Internal Medicine, Kyushu University, Fukuoka City, Japan.
Biochim Biophys Acta. 1997 Nov 28;1362(1):87-96. doi: 10.1016/s0925-4439(97)00071-9.
This study was performed to clarify the presence of sodium-dependent glucose uptake and its role in the synthesis of type IV and type VI collagen by cultured bovine retinal pericytes. The glucose uptake by retinal pericytes and retinal endothelial cells was measured using 3H-D-glucose in the presence or absence of sodium. Glucose uptake in the presence of sodium was twice as high as that observed in the presence of phlorizin and sodium or in the absence of sodium. Sodium-dependent glucose uptake was observed at different sodium concentrations, and its half-maximal stimulation occurred at 48 mM. These findings were not observed in retinal endothelial cells. Levels of type IV and type VI collagen produced by retinal pericytes were significantly increased at glucose concentrations higher than 20 mM. Phlorizin decreased both collagen synthesis and glucose consumption by retinal pericytes incubated with 30 mM of glucose to the levels observed with 5 mM of glucose. These data suggest that sodium-dependent glucose uptake is present in retinal pericytes and that excessive glucose entry into the cell is an important factor for overproduction of collagen. Phlorizin normalized the synthesis of type IV and type VI collagen with decreasing glucose consumption under high glucose conditions.
本研究旨在阐明钠依赖性葡萄糖摄取的存在及其在培养的牛视网膜周细胞合成IV型和VI型胶原中的作用。在有或无钠存在的情况下，使用³H-D-葡萄糖测量视网膜周细胞和视网膜内皮细胞对葡萄糖的摄取。在有钠存在的情况下，葡萄糖摄取量是在存在根皮苷和钠或无钠情况下观察到的两倍。在不同的钠浓度下均观察到钠依赖性葡萄糖摄取，其半最大刺激浓度出现在48 mM。在视网膜内皮细胞中未观察到这些结果。当葡萄糖浓度高于20 mM时，视网膜周细胞产生的IV型和VI型胶原水平显著增加。根皮苷将与30 mM葡萄糖一起孵育的视网膜周细胞的胶原合成和葡萄糖消耗降低至与5 mM葡萄糖一起孵育时观察到的水平。这些数据表明，视网膜周细胞中存在钠依赖性葡萄糖摄取，并且过量的葡萄糖进入细胞是胶原过度产生的重要因素。在高糖条件下，根皮苷通过减少葡萄糖消耗使IV型和VI型胶原的合成恢复正常。
