Related Experiment Videos
Red cell metabolic alterations in postnatal life in term infants: possible control mechanisms
Insights
Red blood cell enzyme activity in infants changes with declining fetal hemoglobin, not red cell age. Inorganic phosphorus influences glycolytic intermediates, indicating unique fetal red cell changes during erythropoiesis.
Area of Science:
- Biochemistry
- Neonatology
- Hematology
Background:
- Red blood cell (RBC) metabolism shifts after birth.
- Fetal hemoglobin (HbF) concentration declines postnatally.
- RBC enzyme activity and glycolytic intermediates are crucial for cellular function.
Purpose of the Study:
- To investigate correlations between RBC glycolytic intermediates and enzymes with fetal hemoglobin levels and red cell age in term infants.
- To understand the influence of plasma inorganic phosphorus (Pi) on these metabolic pathways.
Main Methods:
- Correlation analysis of RBC glycolytic intermediates and enzymes.
- Measurement of fetal hemoglobin concentration (%F).
- Assessment of intra- and extracellular venous pH, plasma inorganic phosphorus (Pi), and pyruvate kinase (PK) activity.
Main Results:
- Non-age-dependent enzymes (phosphoglycerate kinase, enolase, phosphofructokinase) correlated significantly with the decline in %F, not PK activity.
- Age-dependent enzymes (hexokinase, glucose-6-phosphate dehydrogenase) correlated with PK activity.
- Plasma Pi concentration significantly impacted glucose-6-phosphate levels, suggesting an extracellular influence on glycolytic intermediates.
Conclusions:
- Postnatal changes in specific RBC enzymes are linked to the transition from fetal to adult erythropoiesis.
- Plasma inorganic phosphorus plays a role in modulating RBC glycolytic pathways in term infants.
- These findings highlight distinct metabolic adaptations in fetal vs. adult red blood cells.
Abstract:
Red cell glycolytic intermediates and enzymes in term infants in the first year of life were correlated with the fetal hemoglobin concentration (%F), intra- and extracellular venous pH, plasma inorganic phosphorus (Pi) and pyruvate kinase (PK) activity. Changes in the non-age-dependent enzymes phosphoglycerate kinase, enolase, and phosphofructokinase correlated most significantly with the postnatal decline in %F (P less than 0.001), not the age of the red cell population, as reflected in PK activity. The age-dependent enzymes, hexokinase and glucose-6-phosphate dehydrogenase, however, correlated well with PK activity (P less than 0.001). The concentration of glucose-6-phosphate did not correlate significantly with the postnatal decline in %F (P greater than 0.05) or PK (P greater than 0.10), but correalted significantly with the plasma Pi concentration (P less than 0.001). "Total triose phosphate" and 2,3-diphosphoglycerate did not correlate with Pi. It appears from these studies that an extracellular factor, Pi alters the pattern of glycolytic intermediates in term infants and that the postnatal changes in phosphoglycerate kinase, enolase, and phosphofructokinase are unique to the "fetal" red cell and reflect passage from fetal to "adult" erythropoiesis.