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Hepatic mitochondrial fatty acid oxidation during the perinatal period in the rat
Insights
Hepatic mitochondrial enzymes involved in fatty acid oxidation, such as carnitine acyltransferase I, show rapid increases post-birth. These changes are influenced by maternal diet and pregnancy duration, impacting fetal liver enzyme activity.
Area of Science:
- Biochemistry
- Developmental Biology
- Metabolism
Background:
- Hepatic mitochondrial enzymes play a crucial role in fatty acid oxidation.
- Developmental changes in these enzymes are critical for neonatal adaptation.
- Carnitine acyltransferase I and acyl-CoA synthetase are key enzymes in this pathway.
Purpose of the Study:
- To investigate the developmental changes in hepatic mitochondrial enzymes after birth.
- To compare the activity patterns of carnitine acyltransferase I, carnitine acyltransferase II, and acyl-CoA dehydrogenase.
- To explore the influence of maternal factors on fetal liver enzyme activity.
Main Methods:
- Enzyme activity assays were performed on liver samples at different developmental stages.
- Studies included comparisons between suckling and weaned animals.
- Maternal dietary interventions and pregnancy conditions were manipulated.
Main Results:
- Carnitine acyltransferase I activity increased rapidly after birth, peaking during suckling and declining post-weaning.
- Acyl-CoA synthetase activity also increased rapidly post-birth, with a major surge within 3 hours.
- Carnitine acyltransferase II and acyl-CoA dehydrogenase showed minimal developmental changes.
- Maternal factors like prolonged pregnancy, starvation, or high polyunsaturated fat diet increased fetal liver acyl-CoA synthetase and carnitine acyltransferase I activity.
Conclusions:
- Hepatic mitochondrial carnitine acyltransferase I and acyl-CoA synthetase exhibit significant postnatal developmental increases.
- These enzymes are more responsive to developmental cues than carnitine acyltransferase II and acyl-CoA dehydrogenase.
- Maternal nutrition and pregnancy status can prenatally influence fetal liver enzymes critical for fatty acid metabolism.
Abstract:
1. The activity of hepatic mitochondrial carnitine acyltransferase I increases rapidly after birth, is high during the suckling period and falls after weaning. In contrast, carnitine acyltransferase II and acyl-CpA dehydrogenase exhibit few developmental changes. 2. These and previous studies indicate that outer mitochondrial membrane acyl-CoA synthetase and inner membrane carnitine acyltransferase I increase in activity after birth much more rapidly than to any other enzymes of fatty acid oxidation. 3. Studies of the 18 hr after caesarian delivery indicate that whereas the major increase in the activity of acyl-CoA synthetase occurs within 3 hr of birth the change in carnitine acyltransferase I activity is less rapid. 4. Prolonged pregnancy, starvation of the mother or feeding the mother a high polyunsaturated fat content diet resulted in increased activities of acyl-CoA synthetase and carnitine acyltransferase I in the fetal liver.