Division of Endocrinology, Diabetes, and Hypertension, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
OBJECTIVE: Inflammation may have a major role in the pathogenesis and prognosis of critical illness. Hyperglycemia increases levels of the inflammatory cytokine interleukin-6 (IL-6) and is associated with increased risks of morbidity and mortality. Because hypoglycemia is also associated with adverse outcomes, we tested the hypothesis that hypoglycemia increases IL-6. RESEARCH DESIGN AND METHODS: Seventeen healthy men and women participated in hypoglycemic and euglycemic-hyperinsulinemic clamp studies (target blood glucose levels 2.7 and 5.0 mmol/l, respectively), separated by 1-3 months. IL-6, ACTH, and cortisol were measured at baseline and at 45, 75, 105, and 135 min after initiation of the insulin infusion. RESULTS: IL-6, ACTH, and cortisol levels increased significantly (P < 0.0001) during hypoglycemia but not euglycemia. IL-6 increased from mean +/- SEM 1.0 +/- 0.2 pg/ml at baseline to 2.6 +/- 0.2 pg/ml after 135 min of hypoglycemia, whereas IL-6 levels were unchanged during euglycemia. CONCLUSIONS: Hypoglycemia increases IL-6 levels in healthy individuals.