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Effect of neonatal undernutrition upon cerebroside sulfate degradation in the developing rat brain
M C Brown1, J N Larocca, C Sato
1Departamento de Quimica Biologica, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires, IQUIFIB (CONICET-UBA) Argentina.
Insights
Undernourished rats show negligible in vivo degradation of brain cerebroside sulfates. This impaired catabolism, not Arylsulfatase A deficiency, contributes to galactolipid accumulation in starvation.
Area of Science:
- Neuroscience
- Biochemistry
- Developmental Biology
Background:
- Decreased accumulation of cerebroside sulfates is observed in undernourished rats.
- Galactolipids are crucial components of brain development.
Purpose of the Study:
- To investigate if reduced cerebroside sulfate accumulation in undernourished rats is due to increased catabolism.
- To determine the in vivo degradation rate of brain cerebroside sulfates in normal versus undernourished rats.
Main Methods:
- Intracranial injection of a cerebroside sulfate precursor in 18-day-old rats.
- Intraperitoneal injection of unlabeled sodium sulfate (chase).
- Measurement of labeled cerebroside sulfates in the brain up to 48 hours post-chase.
Main Results:
- Normal rats showed significant degradation of cerebroside sulfates (41-55% reduction by 48h).
- Undernourished rats exhibited negligible degradation, with radioactivity remaining constant.
- Arylsulfatase A activity patterns were similar in both groups, ruling out enzyme deficiency.
Conclusions:
- Undernutrition significantly impairs the in vivo degradation of brain cerebroside sulfates.
- The lack of catabolism, rather than Arylsulfatase A deficiency, contributes to altered galactolipid levels in starved rats.
- This finding highlights a critical metabolic disruption in the developing brain during starvation.
Abstract:
In order to find out if the decreased accumulation of cerebroside sulfates observed in 21-d-old undernourished rats was in part the result of an increased rate of catabolism of these galactolipids, the in vivo degradation of brain cerebroside sulfates was studied in 18-d-old normal and undernourished rats. Two hours after the intracranial injection of the precursor (0 time), the animals were injected intraperitoneally with unlabeled sodium sulfate. Labeled cerebroside sulfates were measured in the brain up to 48 h after the chase. In normal animals, the radioactivity decreased at 24 h and 48 h to 55% and 41%, respectively, of the value obtained at 0 time. In undernourished animals, degradation was negligible, since the radioactivity attained at 0 time remained almost constant up to 48 h. The lack of in vivo degradation of cerebroside sulfates observed in the starved rats cannot be explained by a deficiency of Arylsulfatase A, since the pattern of activity of the enzyme was similar in both groups of animals.