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Institutes of
* General Pathology,
Human Anatomy,
§ Medical Sciences, and
¶ Human Physiology II, Faculty of Medicine, University of Milan, Milano, Italy; and
Gife Laboratory, Lugano, Switzerland
1Correspondence: Institute of General Pathology, University of Milan, Via Mangiagalli, 31, I-20133 Milan, Italy. E-mail: Giuseppe.Scalabrino{at}unimi.it
We have recently demonstrated that the myelinolytic lesions in the
spinal cord (SC) of rats made deficient in vitamin B12
(cobalamin) (Cbl) through total gastrectomy (TG) are tumor necrosis
factor-
(TNF-
)-mediated. We investigate whether or not permanent
Cbl deficiency, induced in the rat either through TG or by chronic
feeding of a Cbl-deficient diet, might modify the levels of three
physiological neurotrophic factorsepidermal growth factor (EGF),
vasoactive intestinal peptide (VIP), and somatostatin (SS)in the
cerebrospinal fluid (CSF) of these rats. We also investigated the
ability of the central nervous system (CNS) in these Cbl-deficient rats
to synthesize EGF mRNA and of the SC to take up labeled Cbl in
vivo. Cbl-deficient rats, however the vitamin deficiency is
induced, show a selective decrease in EGF CSF levels and an absence of
EGF mRNA in neurons and glia in various CNS areas. In contrast,
radiolabeled Cbl is almost exclusively taken up by the SC white matter,
but to a much higher degree in totally gastrectomized (TGX) rats.
Chronic administration of Cbl to TGX rats restores to normal both the
EGF CSF level and EGF mRNA expression in the various CNS areas
examined. This in vivo study presents the first evidence
that the neurotrophic action of Cbl in the CNS of TGX rats is mediated
by stimulation of the EGF synthesis in the CNS itself. It thus appears
that Cbl inversely regulates the expression of EGF and TNF-
genes in
the CNS of TGX rats.Scalabrino, G., Nicolini, G., Buccellato, F. R., Peracchi, M., Tredici, G., Manfridi, A., Pravettoni, G. Epidermal
growth factor as a local mediator of the neurotrophic action of vitamin
B12 (cobalamin) in the rat central nervous system.
Key Words: cerebrospinal fluid epidermal growth factor subacute combined degeneration totally gastrectomized rat
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