Table 4.
Effects of insulin and elevated D-glucose on amino acid and 2-deoxy-D-glucose transport in human umbilical vein endothelial cells isolated from gestational diabetic pregnancies
| Transport (pmol (μg protein)−1 min−1) | ||||||
|---|---|---|---|---|---|---|
| Condition | l-Lysine | l-Citrulline | l-Leucine | l-Serine | l-Cystine | 2DG |
| 5 mm D-glucose | 4·3 ± 0·1 | 1·9 ± 0·5 | 5·3 ± 0·7 | 1·8 ± 0·7 | 1·8 ± 0·7 | 3·5 ± 0·9 |
| 5 mm D-glucose + insulin | 2·1 ± 0·1 * | 1·9 ± 0·3 | 4·8 ± 0·6 | 2·1 ± 0·4 | 2·2 ± 0·5 | 3·8 ± 0·8 |
| 25 mm D-glucose | 4·6 ± 0·2 | 1·9 ± 0·9 | 4·6 ± 1·2 | 1·8 ± 0·2 | 2·3 ± 0·3 | 4·1 ± 0·9 |
| 25 mm D-glucose + insulin | 4·5 ± 0·1 | 2·1 ± 0·1 | 4·9 ± 0·3 | 1·8 ± 0·5 | 2·2 ± 0·6 | 3·8 ± 0·7 |
Diabetic endothelial cells were cultured in M199 containing 20 % serum and either 5 or 25 mm D-glucose in the absence or presence of 1 nM insulin added during the last 8 h of a 24 h incubation period. Cells were then incubated in Krebs solution and initial rates of transport measured over 30-120 s. Values denote the means ± s.e.m. of n = 3 different cell cultures
P < 0·04 relative to values in 5 or 25 mm D-glucose or 25 mm D-glucose + insulin. All other values for L-lysine transport were significantly (P < 0·04) elevated compared with non-diabetic cells cultured in 5 mm D-glucose (L-lysine: 2·9 ± 0·5 pmol (μg protein)−1 min−1, n = 4 paired experiments). 2DG, 2-deoxy-D-glucose.