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[Dynamics of carbohydrate metabolism in the heart muscle in early ontogenesis]
Insights
Postnatal heart muscle shows declining glycolytic activity after birth, stabilizing by 15-20 days. Key enzyme changes suggest adaptive inhibition of glycolysis alongside increased mitochondrial capacity during early development.
Area of Science:
- Biochemistry
- Developmental Biology
- Cardiovascular Physiology
Context:
- Investigates metabolic shifts in the heart during the early postnatal period.
- Focuses on the interplay between glycolysis, glycogenolysis, and mitochondrial function.
- Examines enzymatic activity changes in cardiac muscle homogenates and extracts.
Purpose:
- To elucidate the dynamic changes in glycolysis and glycogenolysis in the heart after birth.
- To correlate these metabolic changes with alterations in specific glycolytic enzyme activities.
- To understand the adaptive mechanisms regulating energy metabolism during early cardiac ontogenesis.
Summary:
- Glycolytic activity in the heart muscle decreases post-birth, stabilizing around 15-20 days.
- While some enzymes like aldolase and hexokinase show slight declines, phosphofructokinase and lactate dehydrogenase activities increase significantly (50-60%).
- These findings suggest a coordinated regulation where increasing mitochondrial capacity is paralleled by adaptive inhibition of glycolytic phosphorylation, maintaining overall glycolytic and glycogenolytic potential.
Impact:
- Provides insights into the developmental regulation of cardiac energy metabolism.
- Highlights the adaptive strategies employed by the heart to balance substrate utilization during ontogenesis.
- Offers a basis for understanding metabolic disturbances in congenital heart conditions.
Abstract:
The dynamics of glycolysis and glycogenolysis in the postnatal period, determined from the accumulation of lactate in the homogenate of the heart muscle, indicates that the glycolytic activity begins to subside right after the birth and becomes constant after a lapse of 15-20 days. The activity of the phosphorylase, phosphohexoisomerase, enolase and pyruvate-kinase in the heart muscle extract was found to remain virtually unchanged. Some decline is noted in the activity of the aldolase and hexokinase, while that of the phosphofructokinase and lactate-dehydrogenase rises by 50-60 per cent. These data suggest that in the early ontogenesis the increasing capacity of the mitochondrial system in the heart muscle is paralled by an adjustable conditioned inhibition of the glycolytic phosphorylation, with concurrently rising activity of the phosphofructokinas and, consequently, also of the potential capacity of glycolysis and glycogenolysis.