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Effects of age and biotin status on postnatal development of plasma biotinidase activity in rats
G S Heard1, R W Tanner, T L Blevins
1Department of Human Genetics, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0169.
Insights
Neonatal biotinidase activity in rats mirrors human development, unaffected by maternal biotin deficiency. This suggests biotin-depleted rat pups are valuable models for studying biotinidase deficiency disorders.
Area of Science:
- Biochemistry
- Developmental Biology
- Nutritional Science
Background:
- Biotinidase is crucial for biotin recycling.
- Biotinidase deficiency in humans causes severe developmental abnormalities.
- Understanding biotinidase development is essential for diagnosing and treating deficiencies.
Purpose of the Study:
- To investigate the developmental pattern of biotinidase activity in neonatal rats.
- To determine if maternal biotin depletion affects neonatal biotinidase activity.
- To evaluate the utility of biotin-depleted neonatal rats as a model for human biotinidase deficiency.
Main Methods:
- Plasma biotinidase activity was measured in rat pups from control and biotin-depleted dams at various postnatal days.
- Plasma albumin concentrations were also measured.
- Statistical analyses were performed to compare groups and assess correlations.
Main Results:
- Biotinidase activity increased significantly until postnatal day 14, then slightly declined by day 21 in both control and depleted groups.
- No significant differences in biotinidase activity were observed between pups from control and biotin-depleted dams.
- Plasma biotinidase activity and albumin concentration were significantly correlated.
Conclusions:
- Maternal biotin depletion does not impact the developmental trajectory of biotinidase activity in neonatal rats.
- Neonatal biotin-depleted rats exhibit developmental changes in biotinidase activity similar to human newborns.
- These rats serve as a reliable model for studying developmental abnormalities in human biotinidase deficiency.
Abstract:
Biotinidase activity was measured in plasmas of 1-, 7-, 14-, and 21-day-old rats from control dams and dams that had been fed a biotin-depleting diet from Day 15 of gestation. Biotinidase activity increased significantly in the plasma of rats from control and depleted mothers until Postnatal Day 14, after which there was a small but significant decline at Day 21. Differences between the mean activities of the two groups of pups on each sampling day were not significant and there were no significant differences in activity levels attributable to sex. Plasma albumin concentrations increased from birth until Day 21, and plasma biotinidase activity and albumin concentration were significantly correlated (r = +/- 0.43). We suggested that these two proteins may be controlled by a common mechanism in the early postnatal period, and that biotin deficiency does not affect the development of biotinidase activity. Because biotin-depleted neonatal pups show developmental changes in biotinidase activity similar to those of human newborns, and they can be produced reliably by depleting dams from Day 15 of gestation, they may be useful models for studying the developmental abnormalities associated with human biotinidase deficiency.