Reproducibility of glycaemic thresholds for activation of counterregulatory hormones and hypoglycaemic symptoms in healthy subjects.

Nine healthy subjects were studied on two separate occasions, at least two weeks apart, using the glucose clamp technique to produce a gradual hypoglycaemia. Glucose thresholds for neuroendocrine and symptom responses varied up to 1.5 mmol/l between subjects. There was a significant correlation between individual glucose thresholds on day 1 and 2 for adrenaline (p = 0.0008), growth hormone (p = 0.007) and pancreatic polypeptide (p = 0.02), and for autonomic (p = 0.018) and neuroglycopoenic (p = 0.023) symptoms, whereas no significant correlations were found for glucagon and cortisol. The mean intra-individual differences in glucose thresholds between day 1 and 2 were 0.22 mmol/l for the hormones and 0.25 mmol/l for the symptoms. We conclude that healthy subjects differ in hypoglycaemic thresholds, and that the difference reflects individual variation.