Figure 1. Effects of elevated D-glucose on L-arginine transport in human umbilical vein endothelial cells isolated from gestational diabetic pregnancies.

L-Arginine transport (100 μM, 1 min, Krebs buffer) was measured in third passage diabetic endothelial cells after incubation of cells for 0-48 h in M199 containing 20 % serum and either 5 mm (^), 25 mm D-glucose (•) or 5 mm D-glucose + 20 mm D-mannitol (data not shown). After 48 h all culture media were replaced with M199 containing 20 % serum and 5 mm D-glucose (48-96 h) and L-arginine transport was measured in Krebs solution containing 5 mm D-glucose. The dotted line represents L-arginine transport in non-diabetic endothelial cells cultured in 5 mm D-glucose + 20 mm D-mannitol (replotted from Fig. 1 in Sobrevia et al. 1996). Values denote the means ±s.e.m. of experiments in 7 different cell cultures.