Gene expression of neurotrophins and their receptors in lead nitrate-induced rat liver hyperplasia

Neurotrophins including nerve growth factor (NGF), brain-derived neurotroph ic factor (BDNF), and neurotrophin-3 (NT-3) are known to play important rol es in the survival, proliferation, differentiation, and/or maintenance of f unction in several tissues including neuronal tissues. The role of neurotro phins in liver tissue, however, has not yet been clarified. In the present study, we assessed the temporal change in gene expression of neurotrophins, NGF, BDNF, and NT-3, and their receptors, low affinity neurotrophin recept or (p75NTR) and Trks A, B, and C, by RT-PCR technique in the liver of rats treated with lead nitrate (LN; 0.1 mmol/kg body weight), an inducer of live r hyperplasia. The mRNAs for NGF, BDNF with exon 4, NT-3, p75NTR, and all T rk members were detected in the LN-untreated liver. LNtreatment resulted in increases in the levels of NGF, BDNF with exon 4, NT-3, p75NTR, and TrkA m RNAs and further led to expression of BDNF mRNA with exon 3. The increase i n gene expression of neurotrophins and their receptors was closely correlat ed with those in liver weight. In this report, we propose for the first tim e that neurotrophins may play crucial roles in LN-induced liver hyperplasia . (C) 2000 Academic Press.