Lactate distribution and metabolism during and after anoxia in the
turtle, chrysemys picta bellii.
Jackson, D. C., V. I. Toney, and S. Okamoto.
Department of Physiology, Brown University, Providence, RI
02912
APStracts 3:0087R, 1996.
To determine the fate of lactate during and following prolonged
anoxia, 14C-labeled lactate was injected into turtles after 2 h of a
6 h submergence at 20oC. 14C activities of plasma and chamber water
were tested at intervals during anoxia and also in expired air during
39 h of recovery. Partitioning of label in major body compartments
(ECF, ICF, and shell) and 14C activity and glycogen in selected
tissues (heart, liver, and muscle) were measured after anoxia (N=7)
and after recovery (N=6). Shell 14C and [lactate] were extensively
measured on 6 anoxic turtles. During anoxia all 14C remained in the
animal indicating no urine production. At 6 h anoxia 47% of recovered
14C, presumably still as lactate, was in the ECF, 27% in the ICF, and
30% in the shell. During recovery plasma [lactate] fell from 35 to 5
mEq but surrounding water and expired air accounted for only 9 and
8%, respectively, of recovered label. The ICF portion grew to 41%,
associated with a recovery in tissue glycogen. The shell still had
22% of total label. We conclude that during recovery from anoxia
lactate is predominantly resynthesized to glycogen and only a small
fraction is directly oxidized. During anoxia, however, lactate is
widely distributed in the body and a surprisingly large and
functionally significant fraction resides in the shell.
Received 28 August 1995; accepted in final form 23 February 1996.
APS Manuscript Number R536-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 20 March 96