Iron-independent neuronal expression of transferrin receptor mRNA in the rat

Neuronal transferrin receptor protein expression is highly upregulated wide ly in CNS following iron deficiency. Using the medial habenular nucleus as a model of neuronal transferrin receptor mRNA expression, the present study examined 17-day-old rats subjected to variations in dietary iron. Changing the iron availability resulted in alterations in plasma and cerebrospinal fluid (CSF) levels of transferrin and iron. The iron-binding capacity of tr ansferrin in CSF was exceeded in normal and iron-overloaded rats. In spite of a lowering of the concentration of brain iron by approximately 22% in ir on-deficient rats, neuronal transferrin receptor mRNA was not affected when measured by quantitative densitometry, Brain iron and neuronal transferrin receptor mRNA expression was unaltered in iron overloaded rats. The absenc e of a rise in transferrin receptor mRNA during iron deficiency suggests th at neuronal transferrin receptor mRNA expression is regulated by another me chanism than the post-transcriptional regulation mechanism, which has been attributed to cells of non-neural tissue. (C) 1999 Elsevier Science B.V. Al l rights reserved.