Distribution of NOS in normoxic vs. hypoxic rat lung: upregulation of NOS by chronic hypoxia

摘要: Expression and localization of nitric oxide synthase (NOS) in the lungs chronically hypoxic normoxic rats were studied using both immunohistochemistry NADPH diaphorase (NADPH-d) staining techniques. In rat, NOS was detected by methods endothelium large pulmonary vessels epithelium bronchi bronchioli. expression not resistance but prominently expressed these after 2-4 wk chronic hypoxia. contrast to small vessels, bronchial exhibited immunostaining lungs. Hypoxia also found induce de novo smooth muscle muscle. enzyme activity lung homogenates assessed [3H]arginine [3H]citrulline conversion. The soluble NOS, particulate increased These results demonstrate hypoxia-induced upregulation protein rat lung, suggesting a potentially important role adaptation circulation lack is consistent with physiological studies that NO may be involved mechanism for maintaining normally low vascular resistance.