Composition of Gomori‐positive inclusions in astrocytes of the hypothalamic arcuate nucleus

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Abstract
Background: Astrocytes within the hypothalamic arcuate nucleus contain Gomori‐positive inclusions that exhibit a nonenzymatic peroxidase activity. The source and composition of these Gomori‐positive inclusions are currently unknown. Recent evidence, derived from cultured astrocytes, suggests that Gomori‐positive inclusions may consist of autophagocytized accumulations of altered mitochondria and that the peroxidase activity is generated by iron or other metals which accumulate in these mitochondria. Methods: The present study applies electron microscopy, energy dispersive X‐ray microanalysis, and immunocytochemistry in conjunction with confocal microscopy to determine the structure and composition of Gomori‐positive inclusions in vivo. Results: The results indicate that Gomori‐positive inclusions are heterogeneous structures often associated with microtubules and that they contain conspicuous mitochondrial components. Gomori‐positive inclusions exhibit X‐ray emission peaks for copper and, less often, chromium, either of which could account for the peroxidase activity. Conclusions: These results support the hypothesis that Gomori‐positive inclusions are autophagosomes in which mitochondria are prominent.