Human cerebral blood flow and metabolism in acute insulin-induced hypoglycemia

Richard P. Kennan, Kan Takahashi, Cynthia Pan, Harry Shamoon, Jullie W. Pan

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

How the human brain functions under conditions of acute hypoglycemia remains a complex question by virtue of the potential simultaneous shifts in processes of perfusion, metabolism, and changing demand. We examined this issue by measuring cerebral blood flow (CBF) and oxidative metabolism (CMRO 2) in insulin-induced hypoglycemic (HG) and euglycemic (EG) conditions at rest and during motor activation in normal human subjects using magnetic resonance (MR). Experiments were performed on 12 subjects (9M, 3F). The protocol consisted of insulin-induced hypoglycemia (targeting a HG of 60mg/dL) followed by euglycemia, or in reverse order, each phase lasting approximately 1.5h. Euglycemia was performed with the same insulin infusion rate so as to match the hypoglycemic phase. Magnetic resonance data were acquired 30 mins after the target plasma glucose was achieved so as to minimize any acute effects. Although the depth of hypoglycemia achieved in the present study was relatively small, the present data found a significant increase in flow in motor cortex with mild hypoglycemia, from 56.4±13.6mL/100 g min (euglycemia) to 64.3± 7.6mL/100 g min (hypoglycemia). Using the Renkin-Crone exponential model of oxygen extraction with MR models of susceptibility-based relaxation, analysis of the flow measurements, relaxation and BOLD data also implied that throughout the studies, metabolism and flow remained coupled. Elementary motor task activation was not associated with any consistent larger activated flows. Thus it remains that although mild hypoglycemia induced an increase in basal flow and metabolism, a similar increase was not seen in task activation.

Original languageEnglish (US)
Pages (from-to)527-534
Number of pages8
JournalJournal of Cerebral Blood Flow and Metabolism
Volume25
Issue number4
DOIs
StatePublished - Apr 2005

Fingerprint

Cerebrovascular Circulation
Hypoglycemia
Insulin
Hypoglycemic Agents
Magnetic Resonance Spectroscopy
Basal Metabolism
Motor Cortex
Perfusion
Oxygen
Glucose
Brain

Keywords

  • Functional magnetic resonance
  • Human
  • Hypoglycemia
  • Insulin
  • Perfusion

ASJC Scopus subject areas

  • Endocrinology
  • Neuroscience(all)
  • Endocrinology, Diabetes and Metabolism

Cite this

Human cerebral blood flow and metabolism in acute insulin-induced hypoglycemia. / Kennan, Richard P.; Takahashi, Kan; Pan, Cynthia; Shamoon, Harry; Pan, Jullie W.

In: Journal of Cerebral Blood Flow and Metabolism, Vol. 25, No. 4, 04.2005, p. 527-534.

Research output: Contribution to journalArticle

Kennan, Richard P. ; Takahashi, Kan ; Pan, Cynthia ; Shamoon, Harry ; Pan, Jullie W. / Human cerebral blood flow and metabolism in acute insulin-induced hypoglycemia. In: Journal of Cerebral Blood Flow and Metabolism. 2005 ; Vol. 25, No. 4. pp. 527-534.
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