Counterregulatory Hormone and Symptom Responses to Insulin-Induced Hypoglycemia in the Postprandial State in Humans

Counterregulatory Hormone and Symptom Responses to Insulin-Induced Hypoglycemia in the Postprandial State in Humans Francesca Porcellati , Simone Pampanelli , Paolo Rossetti , Cristina Cordoni , Stefania Marzotti , Luciano Scionti , Geremia B. Bolli and Carmine G. Fanelli From the Section of Internal Medicine, University of Perugia, Perugia, Italy Address correspondence and reprint requests to Carmine G. Fanelli, University of Perugia, Section of Internal Medicine, Via E. Dal Pozzo, 06126 Perugia, Italy. E-mail: cgfanelli{at}interfree.it or fanelli{at}dimisem.med.unipg.it Abstract Plasma counterregulatory hormones and symptoms were measured during hypoglycemia in the postprandial and in the fasting state in humans to establish differences in physiological responses. We studied 8 nondiabetic subjects and 10 subjects with type 1 diabetes on two different occasions during clamped insulin-induced hypoglycemia (2.4 mmol/l) in the sitting position. On one occasion, subjects ate a standard mixed meal, and on the other they remained fasting. In response to postprandial as compared with fasting hypoglycemia, nondiabetic subjects exhibited lower total symptom scores (6.6 ± 0.4 vs. 11.5 ± 0.8, P = 0.001), which was due to less hunger (1.1 ± 0.1 vs. 4.2 ± 0.2), lower suppression of plasma C-peptide (0.23 ± 0.1 vs. 0.08 ± 0.07 nmol/l, P = 0.032), and greater responses of plasma glucagon (248 ± 29 vs. 163 ± 25 ng · l −1 · min −1 , P = 0.018), plasma adrenaline (4.5 ± 0.6 vs. 3.1 ± 0.4 nmol · l −1 · min −1 , P = 0.037), norepinephrine (3.8 ± 0.3 vs. 3.2 ± 0.2 nmol · l −1 · min −1 , P = 0.037), and pancreatic polypeptide (217 ± 12 vs. 159 ± 22 pmol · l −1 · min −1 , P = 0.08). Except for plasma C-peptide, responses in diabetic subjects were similarly affected. Notably, in diabetic subjects responses of glucagon, which were absent in the fasting state, nearly normalized after a meal. In conclusion, in the postprandial compared with the fasting hypoglycemic state, total symptoms are less, but counterregulatory hormones are greater and responses of glucagon nearly normalize in type 1 diabetic subjects. AUC, area under the curve FFA, free fatty acid Footnotes Accepted August 14, 2003. Received May 20, 2003. DIABETES