AJP - Regulatory, Integrative and Comparative Physiology, Vol 250, Issue 2 175-R187, Copyright © 1986 by American Physiological Society
Microcomputer-assisted metabolic studies of voluntary diving of Weddell seals
M. Guppy, R. D. Hill, R. C. Schneider, J. Qvist, G. C. Liggins, W. M. Zapol and P. W. Hochachka
Utilizing a microprocessor-controlled peristaltic withdrawal pump, arterial
blood samples were obtained from Weddell seals (Leptonychotes weddelli)
while diving voluntarily under the sea ice at McMurdo Sound, Antarctica.
Plasma concentrations of glucose, lactate, free fatty acids, urea, and
amino acids were determined in seals at various times during rest, diving,
and recovery. In addition, radiolabeled palmitate, glucose, lactate,
p-aminohippurate, inulin, galactose, and cholate were injected into the
descending aorta of seals in the resting state or during voluntary diving
at sea. Sequential plasma samples were collected, and the kinetics of
wash-in and clearance of each component were determined. Under resting
conditions, the change in specific activity of palmitate, glucose, and
lactate after bolus injection followed smooth multiexponential decay
kinetics as in terrestrial animals. Similar decay curves for the clearance
of organ-specific compounds were also obtained in seals at rest. If, during
voluntary diving, Weddell seals were analogous to exercising animals, the
wash-in and clearance kinetics of all metabolites and organ-specific
compounds would be qualitatively similar to those observed at rest. In
contrast, wash-in and clearance appeared to be qualitatively and
quantitatively modified in a way consistent with utilization of the
classical Scholander diving response in both short and long dives.
