Distribution of neurturin mRNA and immunoreactivity in the peripheral tissues of adult rats.

Abstract

Neurturin (NTN) is a recently discovered neurotrophic factor related to glial cell line-derived neurotrophic factor (GDNF) and has a wide spectrum of biological roles in different types of neurons in the central and peripheral nervous systems. However, information on its expression in peripheral tissues has been limited, and there is no information on its peptide distribution. As a step to examine its role and action mechanisms in neuronal and non-neuronal cells in the periphery, the present study investigated the distribution patterns of its mRNA and peptide in some major peripheral organs of adult rats by in situ hybridization and immunohistochemistry. A widespread expression of NTN mRNA was found in the selected organs of various systems, with a high level in pituitary intermediate lobe, intestine, salivary gland, and testis, and a moderate level in ovary, adrenal gland, kidney, thyroid, and spleen. NTN peptide was also present in the peripheral organs studied, with its distribution corresponding to that of mRNA. In conclusion, NTN is expressed widely in many regionally well-defined cellular systems in various peripheral tissues, suggesting that NTN may act as a target-derived neurotrophic factor for innervating neurons and may have maintenance functions in non-neuronal cells of these adult organs.