AJP - Regulatory, Integrative and Comparative Physiology, Vol 232, Issue 1 10-R17, Copyright © 1977 by American Physiological Society
Acid-base balance and plasma composition in the aestivating lungfish (Protopterus)
R. G. DeLaney, S. Lahiri, R. Hamilton and P. Fishman
Upon entering into aestivation, Protopterus aethiopicus develops a
respiratory acidosis. A slow compensatory increase in plasma bicarbonate
suffices only to partially restore arterial pH toward normal. The cessation
of water intake from the start of aestivation results in hemoconcentration
and marked oliguria. The concentrations of most plasma constituents
continue to increase progressively, and the electrolyte ratios change. The
increase in urea concentration is disproportionately high for the degree of
dehydration and constitutes an increasing fraction of total plasma
osmolality. Acid-base and electrolyte balance do not reach a new
equilibrium within 1 yr in the cocoon.
