The amino-acid pattern in human foetal and maternal plasma at delivery

Crumpler, H. R.; Dent, C. E.; Lindan, O.

doi:10.1042/bj0470223

Cited by 62 publications

(15 citation statements)

References 6 publications

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“…It is apparent that some amino acids, notably serine, have a higher concentration in fetal blood; whereas others, such as the basic amino acids lysine, arginine, and histidine, are approximately at the same concentration in the two blood streams. The total molar concentration of the amino acids measured in this study was 1.7 times greater in fetal blood (4.79 vs. 2.81 mM), in agreement with earlier observations about the a-amino 1430 Lemons, Adcock, Jones, Naughton, Meschia, and Battaglia nitrogen content of maternal and fetal blood (4) or plasma (1,20). Umbilical venous-arterial differences for amino acids.…”

Section: Resultssupporting

confidence: 80%

Umbilical uptake of amino acids in the unstressed fetal lamb.

Ja¹,

Ew²,

Jones³

et al. 1976

J. Clin. Invest.

267

120

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A B S T R A C T The whole blood concentrations of 22 amino acids were measured in a chronic, unstressed fetal lamb preparation. Samples were taken daily from the umbilical artery, umbilical vein, and maternal artery over the latter quaiter of gestation. 73 sets of samples (from the umbilical artery and vein and the maternal artery) from 13 animals were analyzed for amino acid levels. Oxygen contents were determined simultaneously in 48 sets (umbilical artery and vein) to relate fetal oxygen consumption to amino acid uptake via the umbilical circulation.The results indicate that there is no umbilical uptake of the acidic amino acids, glutamate and aspartate; there is, in fact, a net flux of glutamate out of the fetus into the placenta. As both of these amino acids are major constituents of body proteins, the data indicate that they are formed within the fetus. The umbilical uptake of some neutral and basic amino acids (e.g., valine, leucine, isoleucine, arginine, phenylalanine, and tyrosine) is in considerable excess of estimated growth requirements, suggesting that some amino acids undergo extensive transamination and oxidative degradation in the fetus.Finally, the net uptake of nitrogen, carbon, and calories by the growing ovine fetus in the formn of amino acids, glucose, and lactate is compared to estimated requirements as determined in previous studies.

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Section: Resultssupporting

confidence: 80%

Umbilical uptake of amino acids in the unstressed fetal lamb.

Ja¹,

Ew²,

Jones³

et al. 1976

J. Clin. Invest.

267

120

View full text Add to dashboard Cite

show abstract

“…Numerous studies have demonstrated that each amino acid is maintained at higher levels in fetal blood than in maternal blood [3,4,7,9,11,12,17,20,26]. This has occurred even in the face of an elevation in the level of amino acid in maternal blood (4,13,15].…”

Section: Discussionmentioning

confidence: 99%

The Free Amino Acids of Serum During Development of Macaca mulatto II. During Pregnancy and Fetal Life

Kerr

1968

Pediatr Res

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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-GH 3 -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-GH 3 -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-GH 3 -histidine and valine were significantly elevated at the earliest gestational age. The mean cord: maternal value for all amino acids studied showed a progressive decrease with increasing fetal maturity.

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“…Low plasma a-amino nitrogen concentra tion is a general feature of late pregnancy [Christensen and Streicher, 1948], which may be explained by the fact that amino acids are actively accumulated by the placenta [Batta glia and Meschia, 1978] and transferred to the fetus, thus resulting in a high fetal/maternal plasma amino acid ratio [Crumpler et al, 1950], However, pregnant rats as well as preg nant women already show a hypoaminoacidemia at a stage when the weight of the feto placental unit is still negligible, as it is the case on the 12th day of pregnancy in the rat [Palou et al, 1977] and in the first trimester of human gestation [Schoengold et al, 1978], The decrease in plasma amino acid concen trations during pregnancy is mainly ac counted for by gluconeogenic amino acids and especially by alanine.…”

Section: Introductionmentioning

confidence: 99%

Alanine Turnover Rate and Its Hepatic Metabolism Are Increased in Midpregnant Rat

et al. 1988

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At mid pregnancy (12th day) fed rats exhibit a drop of blood alanine level when the weight of the fetoplacental unit is still negligible. A primed infusion A-V method was used to measure alanine kinetics in fed midpregnant rats and virgin controls, using L-[2,3–³H]alanine as a tracer. Alanine turnover and metabolic clearance rates were higher on day 12 than in virgin controls. The increase in alanine turnover rate was accounted for by an increase in alanine degradation. Since the liver is the main site of alanine degradation, alanine uptake was studied in isolated hepatocytes. Hepatocytes isolated from midpregnant rats utilized 50% more alanine than those from virgin controls. This increase was mainly due to metabolism rather than incorporation into proteins. In conclusion, the alanine turnover rate and its hepatic metabolism are increased in fed midpregnant rats, resulting in the decrease in blood alanine.

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The amino-acid pattern in human foetal and maternal plasma at delivery

Cited by 62 publications

References 6 publications

Umbilical uptake of amino acids in the unstressed fetal lamb.

Umbilical uptake of amino acids in the unstressed fetal lamb.

The Free Amino Acids of Serum During Development of Macaca mulatto II. During Pregnancy and Fetal Life

Alanine Turnover Rate and Its Hepatic Metabolism Are Increased in Midpregnant Rat

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