Expression of growth hormone-releasing factor, growth hormone, insulin-like growth factor-1 and its binding proteins in human lung

Reverse transcription PCR showed that mRNA encoding the neurohormones growt h hormone-releasing factor (GRF) and GH, and its receptor GH-R, together wi th IGF-1 splice variants and IGFBPs are expressed by inflammatory cells fou nd in the normal human airway. Unfractionated BALC moderately express GRF, GH and GH-R, IGFBP-2 to IGFBP-6, and IGFBP-rPI. In addition, BALC preferent ially express the class 1 IGF-1Ea splice variant of the IGF-1 gene. A simil ar pattern of expression occurs in purified AM, except they do not appear t o express GH-R. In marked contrast, AM precursor peripheral blood monocytes , do not express neuropeptides or IGF-1 and only express IGFBP-1, -4 and -6 and IGFBP-rPI. These data suggest that normal human inflammatory airway ce lls possess a powerful array of neurohormones and IGFBPs that are available for modulating local IGF-1 bioavailability in the lung. (C) 2000 Harcourt Publishers Ltd.