AJP - Regulatory, Integrative and Comparative Physiology, Vol 242, Issue 1 85-R88, Copyright © 1982 by American Physiological Society
Free amino acids in the blood of fetal and maternal Weddell seals
B. J. Murphy, P. W. Hochachka, W. M. Zapol and G. C. Liggins
The content of free amino acids in whole blood was measured in near-term
gravid female Weddell seals (Leptonychotes weddelli) and compared with
fetal amino acid profiles during rest and during experimental diving. With
the exception of taurine and glutathione, Ninhydrin-reactive components of
acid extracts of blood occurred in higher concentrations on the fetal side
of the placenta than on the maternal side. Compared with humans the Weddell
seal displayed higher ratios of fetal arterial to maternal arterial levels
for aspartate, glycine, alanine, valine, tyrosine, phenylalanine, and total
branched-chain amino acids. In the resting state the total free amino acid
concentration in maternal blood was only about 70% as large as the total
amino acid concentration in fetal blood, compared with a value of over 80%
for humans. Only modest changes in the concentrations of specific amino
acids occurred during simulated awake diving, but the overall maternal
pools of glycine, glutamate, and glutamine were augmented, creating
favorable conditions for uptake by the fetus.
