HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Am J Physiol Regul Integr Comp Physiol 292: R1033-R1042, 2007. First published September 28, 2006; doi:10.1152/ajpregu.00308.2006
0363-6119/07 $8.00

This Article Free upon publication Full Text Full Text (PDF) All Versions of this Article: 292/2/R1033    most recent 00308.2006v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by MacCormack, T. J. Articles by Driedzic, W. R. Search for Related Content PubMed PubMed Citation Articles by MacCormack, T. J. Articles by Driedzic, W. R.

COMPARATIVE AND EVOLUTIONARY PHYSIOLOGY

The impact of hypoxia on in vivo glucose uptake in a hypoglycemic fish, Myoxocephalus scorpius

Ocean Sciences Centre, Memorial University of Newfoundland, St. John's, Newfoundland, Canada

Submitted 9 May 2006 ; accepted in final form 27 September 2006

The mechanisms controlling carbohydrate utilization in teleost fish are poorly understood, particularly in the heart. Tissue glucose uptake and cardiovascular characteristics were measured in the short-horned sculpin, Myoxocephalus scorpius, a species exhibiting low blood glucose levels, during normoxia and hypoxia to assess the role of adenosine receptors in the control of glucose uptake and anaerobic metabolism. As expected, hypoxia exposure (300 min at 2 mg/l dissolved oxygen) resulted in a bradycardia and plasma lactate accumulation, but glucose uptake rates did not change in heart, brain, gill, spleen, and white muscle. Plasma glucose-to-intracellular glucose ratios indicated that glucose uptake was the rate-limiting step in glucose utilization. The majority of intracellular glucose was unphosphorylated, however, suggesting that hexokinase is also important in controlling the tissue glucose gradient. During hypoxia, the cholinergic blocker atropine resulted in tachycardia but did not significantly change tissue glucose uptake rates or heart and brain adenosine levels. In contrast, the combined treatment of atropine and an adenosine receptor blocker [8-(p-sulfophenyl)theophylline] during hypoxia increased heart glucose uptake to levels fivefold higher than normoxic fish, with no additive effects on cardiovascular parameters. Significant tissue lactate accumulation was observed in this group of fish, signifying that adenosine receptors may depress anaerobic metabolism, even though tissue adenosine accumulation was absent during hypoxia. White muscle accumulated glucose during normoxia, suggesting the presence of gluconeogenic pathways or active uptake mechanisms not previously described in this tissue.

2-deoxyglucose; adenosine receptor; atropine; short-horned sculpin

This article has been cited by other articles:

				S. L. Steele, K. H. A. Lo, V. W. T. Li, S. H. Cheng, M. Ekker, and S. F. Perry Loss of M2 muscarinic receptor function inhibits development of hypoxic bradycardia and alters cardiac {beta}-adrenergic sensitivity in larval zebrafish (Danio rerio) Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2009; 297(2): R412 - R420. [Abstract] [Full Text] [PDF]

				M. Diaz, Y. Vraskou, J. Gutierrez, and J. V. Planas Expression of rainbow trout glucose transporters GLUT1 and GLUT4 during in vitro muscle cell differentiation and regulation by insulin and IGF-I Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2009; 296(3): R794 - R800. [Abstract] [Full Text] [PDF]

				S. Polakof, S. Panserat, E. Plagnes-Juan, and J. L. Soengas Altered dietary carbohydrates significantly affect gene expression of the major glucosensing components in Brockmann bodies and hypothalamus of rainbow trout Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2008; 295(4): R1077 - R1088. [Abstract] [Full Text] [PDF]

				S. Polakof, J. M. Miguez, and J. L. Soengas In vitro evidences for glucosensing capacity and mechanisms in hypothalamus, hindbrain, and Brockmann bodies of rainbow trout Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2007; 293(3): R1410 - R1420. [Abstract] [Full Text] [PDF]