AJP - Regu Information on EB 2010
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Regul Integr Comp Physiol 264: R687-R695, 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 Pinder, A. W.
Right arrow Articles by Smits, A. W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Pinder, A. W.
Right arrow Articles by Smits, A. W.

AJP - Regulatory, Integrative and Comparative Physiology, Vol 264, Issue 4 687-R695, Copyright © 1993 by American Physiological Society

ARTICLES

Mechanisms of acute hemoconcentration in bullfrogs in response to hypoxemia

A. W. Pinder and A. W. Smits
Zoology Department, University of Massachusetts, Amherst 01003.

Three general mechanisms have been proposed to explain rapid increases in red blood cell concentration in vertebrates in response to hypoxia: spleen emptying, red blood cell swelling, and decreases in plasma volume. We have experimentally tested these potential mechanisms for the hemoconcentration of red blood cells associated with hypoxemia in cold (10 degrees C), submerged bullfrogs. The mean increase of hematocrit was approximately 1.4-fold (the increase was highly variable between individual frogs) when arterial oxygen saturation was reduced from 80% to 8% by lowering ambient O2 partial pressure (PO2). The largest response was seen when arterial oxygen saturation was below 33% (a saturation that is not unusual in submerged amphibians). There was no difference between hematocrit increases during hypoxemia in spleen-ligated compared with sham-operated frogs submerged in hyperoxic, normoxic, and hypoxic water, suggesting that spleen emptying is not the primary mechanism. Increased hematocrit was not due to red blood cell swelling: mean corpuscular hemoglobin concentration increased slightly as hematocrit increased, indicating that red blood cells shrank slightly rather than swelling. Plasma volume, measured in a separate group of animals by dilution of 51Cr-labeled autologous red blood cells, decreased almost 50% during hypoxemia, closely correlated with a mean increase of 1.76-fold of hematocrit. We thus conclude that the hematocrit increase seen during hypoxemia in bullfrogs is caused by a loss of plasma volume. This has important implications for cardiovascular function, since blood viscosity, oxygen carrying capacity, and cardiac output are all affected by changes in plasma volume.


This article has been cited by other articles:


Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
M. Busk, F. B. Jensen, and T. Wang
Effects of feeding on metabolism, gas transport, and acid-base balance in the bullfrog Rana catesbeiana
Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2000; 278(1): R185 - R195.
[Abstract] [Full Text] [PDF]


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