Importance of hepatic glucoreceptors in sympathoadrenal response to hypoglycemia.

Abstract

To ascertain whether hepatic glucoreceptors are important to hypoglycemic counterregulation, a localized euglycemic clamp was employed across the liver during general hypoglycemia. Dogs were infused peripherally with insulin (18-21 pmol.kg-1.min-1) for 150 min to induce systemic hypoglycemia. During the liver-clamp (LC) protocol, glucose was infused via the portal vein to maintain euglycemia at the liver. In control experiments, i.e., matched infusion (MI), glucose was infused peripherally at a rate determined to yield similar arterial glycemia levels in the two protocols. Arterial glucose concentrations were not different between protocols during the final hour of insulin infusion (3.26 +/- 0.21 and 3.25 +/- 0.21 mM during LC and MI, respectively; P = 0.91). Calculated hepatic glucose concentrations during the same period were significantly higher for LC (5.22 +/- 0.23 mM) than for MI (3.25 +/- 0.21 mM). During MI, both epinephrine and norepinephrine rose significantly from basal values of 562 +/- 87 pM and 1.21 +/- 0.19 nM to plateaus of 3691 +/- 1097 pM (P = 0.0001) and 2.38 +/- 0.35 nM (P = 0.0002), respectively. However, during LC, the elevation in epinephrine was suppressed by 42 +/- 8% (P = 0.015) relative to MI. Six of seven animals demonstrated a suppression in the norepinephrine response, averaging 32 +/- 13% (NS, P = 0.068). The glucagon response to hypoglycemia was unaffected by the level of hepatic glycemia. Hepatic hypoglycemia is essential to produce the full sympathoadrenal response to insulin-induced hypoglycemia.

• Authors: C M Donovan, J B Halter, R N Bergman
• Journal: Diabetes (Diabetes) Vol. 40 Issue 1 Pg. 155-8 (Jan 1991) ISSN: 0012-1797 [Print] United States
• PMID: 1849847 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Blood Glucose
• Insulin
• Receptors, Cell Surface
• glucose receptor
• Glucagon
• Glucose
• Norepinephrine
• Epinephrine

Topics

• Adrenal Glands (physiopathology)
• Animals
• Blood Glucose (metabolism)
• Dogs
• Epinephrine (blood, metabolism)
• Glucagon (blood)
• Glucose (metabolism)
• Glucose Clamp Technique
• Hypoglycemia (chemically induced, physiopathology)
• Insulin (blood, pharmacology)
• Kinetics
• Liver (metabolism)
• Male
• Norepinephrine (blood, metabolism)
• Receptors, Cell Surface (metabolism)
• Time Factors