AJP - Regu Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Regul Integr Comp Physiol 265: R1036-R1042, 1993;
0363-6119/93 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by King, P. A.
Right arrow Articles by Storey, K. B.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by King, P. A.
Right arrow Articles by Storey, K. B.

AJP - Regulatory, Integrative and Comparative Physiology, Vol 265, Issue 5 1036-R1042, Copyright © 1993 by American Physiological Society

ARTICLES

Adaptations of plasma membrane glucose transport facilitate cryoprotectant distribution in freeze-tolerant frogs

P. A. King, M. N. Rosholt and K. B. Storey
Department of Medicine, University of Vermont, Burlington 05405.

Natural freeze tolerance in several anuran species involves the accumulation of high concentrations of glucose as a cryoprotectant in body fluids and tissues. The present study identifies an important new molecular mechanism supporting freeze tolerance, an adaptive increase in the capacity for facilitated transport of cryoprotectant across plasma membranes by increasing the numbers and/or activity of plasma membrane glucose transporters. Glucose transport by membranes isolated from liver and skeletal muscle was analyzed in two species, the freeze-tolerant wood frog Rana sylvatica and the freeze-intolerant leopard frog Rana pipiens. Membranes from both liver and muscle of R. sylvatica displayed much higher rates of carrier-mediated glucose transport, measured by a rapid filtration technique, compared with corresponding rates for R. pipiens membranes. For the liver Vmax values for glucose transport by membrane vesicles were 69 +/- 18 and 8.4 +/- 2.3 nmol.mg protein-1.s-1 at 10 degrees C for R. sylvatica and R. pipiens, respectively. This difference was due primarily to a greater number of glucose transporters in R. sylvatica liver membranes; the total number of transporter sites, determined by cytochalasin B binding, was 4.7-fold higher in the freeze-tolerant species. For muscle membranes, the Vmax for glucose transport was 4.9 +/- 1 and 0.6 +/- 0.16 nmol.mg-1 x s-1 at 22 degrees C for R. sylvatica and R. pipiens, respectively. However, in muscle there were no differences in the number of membrane transporters between species.(ABSTRACT TRUNCATED AT 250 WORDS)


This article has been cited by other articles:


Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
Y. Voituron, P. Joly, M. Eugene, and H. Barre
Freezing tolerance of the European water frogs: the good, the bad, and the ugly
Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2005; 288(6): R1563 - R1570.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online