EFFECT OF GROWTH-HORMONE ON HUMAN ALVEOLAR MACROPHAGE OXIDATIVE-METABOLISM

Background - Growth hormone (GH) has diverse immunological actions and has been shown to augment oxidative metabolism in rat peritoneal and porcine alveolar macrophages and both human and animal neutrophils. A study was performed to determine the effects of GH on human alveolar m acrophages in vitro. Methods - Macrophages were harvested from 10 pati ents undergoing bronchoalveolar lavage and incubated with 0, 10 and 10 0 nmol/ml GH for four hours. Oxidative metabolism was assessed by mean s of a fluorescent assay using FMLP and E coli as stimulants. Fluoresc ence was measured using flow cytometry. Results - No difference in bas al or stimulated oxidative metabolism was found between the GH and con trol groups. Conclusions - GH does not have a direct stimulatory actio n on human alveolar macrophages in vitro. However, this does not exclu de an indirect effect in vivo. The results contrast with previous stud ies on animal alveolar macrophages.