Relationship between insulin responses to D-glucose and to L-arginine in women with a history of gestational diabetes.

The relationship between insulin responses to glucose and to arginine was studied in non-obese women with previous gestational diabetes (PGD). One group, n = 10, had normal glucose tolerance (NGT) by WHO criteria and another, n = 8, had impaired glucose tolerance (IGT). A third group of women without PGD, n = 12, was also studied. A hyperglycaemic clamp (blood glucose level 11 mM) and an arginine stimulation test (150 mg/kg L-arginine followed by 10 mg/kg.min) were performed on separate days. The ratios of arginine to glucose responses 0-10 min differed: they were 1.00 for non-PGD, 1.29 for NGT and 1.46 for IGT (P < 0.02 vs non-PGD). A further difference between groups was the ratio between first- and second-phase glucose-induced insulin secretion, which was significantly decreased in IGT, 0.72, compared with NGT, 0.98 (P < 0.01), and non-PGD, 1.05 (P < 0.005). However, within each group insulin responses 0-10 min to glucose and arginine were strongly correlated: for NGT (r = 0.75, P < 0.05), for IGT (r = 0.85, P < 0.01) and for women without PGD (r = 0.69, P < 0.05). Insulin sensitivity, as assessed by the M/I ratio, was non-significantly decreased in IGT (0.18 +/- 0.03 mg/kg.min per mU/l vs 0.26 +/- 0.03 in NGT and 0.28 +/- 0.03 in non-PGD, P < 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)