Abstract
Extract: The levels of free amino acids of serum have been investigated during pregnancy and fetal life in the rhesus monkey (Macaca mulatta). Samples of venous blood were drawn simultaneously from the mother and the umbilical cord of the fetus at cesarian section delivery performed at exactly 50, 75, 100, 125, and 150 days conceptual age and at full-term vaginal delivery (168+4 days). Although a wide range of values was found for each amino acid at each age studied (tables I and II), certain trends were evident. All levels of maternal amino acids except those for taurine, lysine, 3-CH3-histidine and arginine were lower at full-term pregnancy than they were in nonpregnant adult animals. This pattern was apparent by 75 days of gestation and was maintained without further change during the remainder of pregnancy.
The sum of the individual values of all free amino acids in fetal blood was highest at 75 days of gestation; this resulted primarily from elevated levels of glutamine and glutamic acid, histidine, methionine, and valine. Levels of 3-CH3-histidine and glycine showed the opposite trend and were higher during late pregnancy than at 75 days of fetal age. The levels of the other amino acids did not undergo significant changes throughout gestation.
At each age studied, the level of each amino acid in fetal blood was higher than that of the corresponding level in maternal blood. The umbilical cord: maternal ratios for alanine, glutamine plus glutamic acid, leucine, 3-CH3-histidine and valine were significantly elevated at the earliest gesta-tional age. The mean cord: maternal value for all amino acids studied showed a progressive decrease with increasing fetal maturity.
Speculation: The dynamics of fetal growth and development in most laboratory animals are sufficiently different from those in the human to make questionable their relevance to human fetal biology. It is generally acknowledged, however, that certain subhuman primates are similar to the human in many aspects of development. This study defines the changes in the free amino acids of serum of fetal and maternal blood that occur during normal pregnancy in the rhesus monkey, and indicates that this species may be used as a suitable experimental model to investigate protein and amino acid metabolism in experiments that cannot be performed during pregnancy and fetal life in the human.
Similar content being viewed by others
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Kerr, G. The Free Amino Acids of Serum During Development of Macaca mulatto II. During Pregnancy and Fetal Life. Pediatr Res 2, 493–500 (1968). https://doi.org/10.1203/00006450-196811000-00007
Issue Date:
DOI: https://doi.org/10.1203/00006450-196811000-00007