Endocrine Abstracts

The factors affecting counterregulatory (CR) responses to hypoglycaemia in T2DM remain uncertain. Previous studies have suggested an effect of glycaemic control on CR responses in T2DM. Little data exists on the effect of treatment with metformin (MET) vs. Sulphonylurea (SUL) on the CR responses to hypoglycaemia in T2DM.

To date, we have performed stepped hypoglycaemic hyperinsulinaemic clamp studies (2-4 mU/kg/min) on 5 subjects treated with MET (Age 50.6, +/- 11.7 years, M: F 4: 1, BMI 30.2 +/- 4.2 kg/m2, DM duration 3.9 +/- 4.3 years, HBA1c 7.2 +/- 0.5 % ) and 3 with SUL. (Age 50 +/- 6.2 years, M: F 2: 1, BMI 28.4 +/- 4.8 kg/m2, DM duration 7.42 +/- 5.5 years). CR did not differ at 3.3 mmol/l and 2.8 mmol/l steps for epinephrine, glucagon, and GH. However cortisol responses were higher in the SUL vs. MET group at the 3.3 mmol (738 +/- 140 vs. 640 +/- 70 nmol/l, p=0.05) and 2.8 mmol/l step (859 +/- 128 vs. 640 +/- 133 nmol/l, p=0.08). HBA1c correlated with cortisol responses at glucose levels of 3.3 mmol/l (r = 0.74) and 2.8 mmol/l (r = 0.85) for all 8 subjects (MET + SUL). In summary cortisol responses to hypoglycaemia were higher in the SUL vs. MET group, and glycaemic control as measured by HbA1c may affect cortisol responses to hypoglycaemia in both groups. These preliminary data may suggest that oral agents have specific effects on the cortisol responses to hypoglycaemia while glycaemic control of T2DM impacts on cortisol responses irrespective of therapy.