title: Hypoglycemia-associated autonomic failure in healthy humans: comparison of two vs three periods of hypoglycemia on hypoglycemia-induced counterregulatory and symptom response 5 days later.
abstract: BACKGROUND
  Hypoglycemia-associated autonomic failure (HAAF) limits the ability of patients with diabetes to achieve target glycemia. Animal models have provided insights into the pathogenesis of HAAF, but a robust human model of HAAF in which recurrent hypoglycemia impacts the counterregulatory responses to hypoglycemia days later is lacking.
  
  
  OBJECTIVE
  The aim of this study was to determine the impact of two or three episodes of moderate hypoglycemia on counterregulatory responses to subsequent hypoglycemia induced 5 days later.
  
  
  METHODS
  Six healthy subjects participated in each of the two study protocols. In both protocol 1 and 2, subjects underwent two 2-hour hypoglycemic clamp studies during the morning and afternoon of day 1. In protocol 2, subjects underwent an additional third hypoglycemic clamp during the morning of day 2. All subjects in both protocols underwent a final hypoglycemic clamp on the morning of day 5.
  
  
  RESULTS
  In protocol 1, there were no significant differences in the hypoglycemia-induced hormone response or in symptoms scores between the mornings of days 1 and 5. In protocol 2, hypoglycemia-induced epinephrine (P = .02) and cortisol (P = .04) secretions were significantly lower on day 5 compared with day 1, whereas glucagon (P = .08) and norepinephrine (P = .59) were not different. Also in protocol 2, neurogenic (P = .02) and neuroglycopenic (P = .04) symptoms during hypoglycemia were decreased on day 5 compared with day 1.
  
  
  CONCLUSIONS
  These results demonstrate that exposure of healthy humans to three 2-hour hypoglycemic episodes over 30 hours leads to significant blunting in counterregulatory and symptom response to subsequent hypoglycemia on day 5.
authors.affiliation: Division of Endocrinology and Diabetes (A.M., A.K., E.R.S.), Department of Medicine, and Division of Biostatistics (L.E.E., J.K., R.R.), School of Public Health, University of Minnesota, Minneapolis, Minnesota 55455.
authors.forename: A
authors.initials: A
authors.lastname: Moheet
authors.forename: A
authors.initials: A
authors.lastname: Kumar
authors.forename: L E
authors.initials: LE
authors.lastname: Eberly
authors.forename: J
authors.initials: J
authors.lastname: Kim
authors.forename: R
authors.initials: R
authors.lastname: Roberts
authors.forename: E R
authors.initials: ER
authors.lastname: Seaquist
mesh_terms: D000328:Adult; D001786:Blood Glucose; D005260:Female; D006801:Humans; D007003:Hypoglycemia / Q000097:blood / Q000150:complications / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D054970:Pure Autonomic Failure / Q000097:blood / Q000209:etiology / Q000503:physiopathology*
chemical_list: D001786:Blood Glucose