Related Experiment Video
Updated: Jul 28, 2026
Isolation and Differentiation of Stromal Vascular Cells to Beige/Brite Cells
Published on: March 28, 2013
Development of peroxisomal beta-oxidation activities in brown fat of perinatal rabbits
1Department of Biological Sciences, George Washington University, Washington, D.C.
Insights
Peroxisomal activity in rabbit brown fat peaks before birth, suggesting a role in development rather than thermogenesis. Mitochondrial activity is highest at birth.
Area of Science:
- Cell Biology
- Developmental Biology
- Metabolic Biochemistry
Background:
- Brown adipose tissue (BAT) is crucial for thermogenesis, particularly in neonates.
- The roles of peroxisomes and mitochondria in developing BAT are not fully understood.
- Peroxisomal and mitochondrial enzyme activities change during perinatal development.
Purpose of the Study:
- To investigate the developmental profile of peroxisomal enzyme activities in rabbit brown fat.
- To compare peroxisomal and mitochondrial enzyme activities during perinatal development.
- To elucidate the specific role of peroxisomes in brown fat development and function.
Main Methods:
- Analysis of peroxisomal enzyme activities (acyl-CoA oxidase, catalase, KCN-insensitive beta-oxidation) in rabbit brown fat.
- Isolation of peroxisomal fractions from brown fat homogenates using sucrose gradient centrifugation.
- Measurement of mitochondrial enzyme activities (cytochrome c oxidase) for comparison.
Main Results:
- Peroxisomal enzyme activities were highest in 25-day fetuses and significantly decreased after birth.
- Mitochondrial enzyme activities, like cytochrome c oxidase, peaked at birth.
- Key beta-oxidation enzymes were found in both peroxisomal and mitochondrial fractions, with higher levels in peroxisomes during fetal development.
Conclusions:
- Peroxisomes exhibit peak activity prior to birth in rabbit brown fat, contrasting with mitochondrial activity.
- Peroxisomes likely play a role in priming brown fat development rather than direct thermogenesis.
- These findings highlight distinct developmental trajectories for peroxisomal and mitochondrial functions in brown adipose tissue.
Abstract:
The development of peroxisomal activities in brown fat was analyzed in perinatal rabbits, 25- and 30-day fetuses, newborns, 5- and 10-day-old pups. Purified peroxisomal fractions were obtained from brown fat homogenates by sucrose gradient centrifugation at a density of 1.22 g/cm3. Enzymes specifically associated with the isolated peroxisomes, acyl-CoA oxidase, catalase and KCN-insensitive beta-oxidation, were most active in 25-day fetuses and much less active after birth. Mitochondrial-associated activities such as cytochrome c oxidase were greatest at birth. The beta-oxidation enzymes, enoyl-CoA hydratase, beta-hydroxyacyl-CoA dehydrogenase, and thiolase were present in mitochondrial as well as peroxisomal fractions. Nevertheless, the levels of these three enzymes in peroxisomes were higher in fetuses. Thus, peroxisomes, in contrast to mitochondria, were most active prior to birth. This suggests that peroxisomes do not participate in brown fat thermogenesis but that they have some role in priming the development of brown fat in perinatal rabbits.
