XXXX is an autocrine or paracrine hormone synthesized and secreted by airway bronchial epithelial cells.

@entity5 @entity1239 @entity1617 @entity1877 @entity6786 @entity28508 @entity934
The role of @entity934 ( @entity1617 ) as a key neurotransmitter in the central and peripheral nervous system is well established. However, the role of @entity1617 may be broader because @entity1617 may also function as an autocrine or paracrine signaling molecule in a variety of nonneuronal tissues. To begin to establish @entity1617 of nonneuronal origin as a paracrine hormone in lung, we have examined neonatal and adult monkey bronchial epithelium for the components involved in nicotinic cholinergic signaling. Using immunohistochemistry and RT-PCR, we have demonstrated in lung bronchial epithelial cells (BECs) expression of @entity1877 acetyltransferase, the vesicular @entity1617 transporter, the @entity1877 high-affinity transporter, alpha7, alpha4, and beta2 nicotinic @entity1617 receptor ( @entity6786 ) subunits, and the @entity6786 accessory protein @entity28508 . Confocal microscopy demonstrates that these factors are expressed in epithelial cells and are clearly distinct from neighboring nerve fibers. Confirmation of RNA identity has been confirmed by partial sequence analysis of PCR products and by cDNA cloning. Primary culture of BECs confirms the synthesis and secretion of @entity1617 and the activity of cholinesterases. Thus, @entity1617 meets all the criteria for an autocrine/paracrine hormone in lung bronchial epithelium. The nonneuronal cholinergic signaling pathway in lung provides a potentially important target for cholinergic drugs. This pathway may also explain some of the effects of @entity1239 on fetal development and also provides additional mechanisms by which smoking affects lung @entity5 growth and development.
