Original Article Antecedent Hindbrain Glucoprivation Does Not Impair the Counterregulatory Response to Hypoglycemia

Recurrent hypoglycemia impairs hormonal counterregula-tory responses (CRRs) to further bouts of hypoglycemia. The hypothalamus and hindbrain are both critical for sens-ing hypoglycemia and triggering CRRs. Hypothalamic glu-cose sensing sites are implicated in the pathogenesis of defective CRRs; however, the contribution of hindbrain glucose sensing has not been elucidated. Using a rat model, we compared the effect of antecedent glucoprivation tar-geting hindbrain or hypothalamic glucose sensing sites with the effect of antecedent recurrent hypoglycemia on CRR to hypoglycemia induced 24 h later. Recurrent hypo-glycemia decreased sympathoadrenal (1,470 325 vs. 3,811 540 pg/ml in controls [t 60 min], P 0.001) and glucagon secretion (222 43 vs. 494 56 pg/ml in controls [t 60]), P 0.003) in response to hypoglycemia. Ante