Unaltered cerebral blood flow during hypoglycemic activation of the sympathochromaffin system in humans

W. J. Powers, P. J. Boyle, I. B. Hirsch, P. E. Cryer

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

To determine if increases in plasma epinephrine and norepinephrine caused by hypoglycemia are associated with increments in cerebral blood flow (CBF), we measured CBF with positron emission tomography in normal humans at ambient fasting arterial plasma glucose levels and at clamped plasma glucose levels of 5.3, 3.5, and 2.8 mmol/l using the hyperinsulinemic, stepped hypoglycemic clamp technique. Despite significant increases in plasma epinephrine to 7,340 ± 350 (SE) pmol/l and in plasma norepinephrine to 3.32 ± 0.35 nmol/l, mean hemispheric CBF (41 ± 1, 49 ± 1, 48 ± 2, and 51 ± 3 ml · 100 g-1 · min-1) remained constant at the ambient (5.2), 5.3, 3.5, and 2.8 mmol/l glycemic levels, respectively. Furthermore, there was no correlation between CBF and either plasma epinephrine levels ranging from 160 to 10,580 pmol/l or plasma norepinephrine levels ranging from 0.56 to 5.10 nmol/l. Failure to demonstrate any dose-response relationship between plasma catecholamine levels and CBF argues against their primary role in cerebrovascular control during hypoglycemia.

Original languageEnglish
Pages (from-to)R883-R887
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume265
Issue number4 34-4
DOIs
StatePublished - 1993

Keywords

  • epinephrine
  • glycemic thresholds during hypoglycemia
  • hypoglycemia
  • norepinephrine

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