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Development of enzymes of energy metabolism in rat heart
Insights
Enzymatic activity in developing rat hearts shows significant changes. Key enzymes like hexokinase decrease postnatally, while others like ATPase and citrate synthase increase substantially, reflecting metabolic maturation.
Area of Science:
- Biochemistry
- Developmental Biology
- Cardiology
Background:
- Cardiac metabolism undergoes significant shifts during development.
- Understanding enzyme activity changes is crucial for comprehending heart maturation.
Purpose of the Study:
- To investigate the developmental profiles of various cardiac enzymes in rats.
- To elucidate the temporal changes in enzyme activity from fetal stages to adulthood.
Main Methods:
- Enzyme activity assays were performed on rat heart tissue.
- Samples were collected from embryonic day (E) 17 to adult stages.
Main Results:
- Hexokinase activity was highest in the fetal period, decreasing at birth.
- Alpha-glycerophosphate dehydrogenase and oxidase activities diverged post-day 15.
- Citrate synthase, succinate dehydrogenase, and ATPase activities increased significantly (2- to 20-fold).
- Adenylate kinase showed constant activity; AMP deaminase and creatine kinase increased during development.
Conclusions:
- Rat heart development involves distinct dynamic changes in key metabolic enzymes.
- These enzymatic shifts are critical for adapting cardiac function from fetal to adult life.
Abstract:
The behavior of several enzymes was studied during rat heart development (4 days before birth to adult stage). Hexokinase has its highest activity during the fetal period; it decreases at birth and remains with low activity in the adult. The alpha-glycerophosphate dehydrogenase and alpha-glycerophosphate oxidase profiles are similar up to the 15th day of development. From there onwards, both profiles diverge, the cytoplasmic activity increasing 3-fold, while the mitochondrial activity remains unchanged. The developmental profiles of the malate dehydrogenases are almost parallel. The development of citrate synthase and succinate dehydrogenase results in a 2- to 4-fold increase in their activities. However, ATPase increases dramatically (20-fold) over the same period. With respect to the enzymes of the adenine nucleotide metabolism, adenylate kinase is fully expressed throughout all ages examined, showing no variation during development. AMP deaminase and creatine kinase increase during development, the cytoplasmic creatine kinase reaching a high level at birth whereas the increases of the mitochondrial enzymes take place gradually during development.