Abstract

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 macrophages in vitro. METHODS: Macrophages were harvested from 10 patients undergoing bronchoalveolar lavage and incubated with 0, 10 and 100 nmol/ml GH for four hours. Oxidative metabolism was assessed by means of a fluorescent assay using FMLP and E coli as stimulants. Fluorescence was measured using flow cytometry. RESULTS: No difference in basal or stimulated oxidative metabolism was found between the GH and control groups. CONCLUSIONS: GH does not have a direct stimulatory action on human alveolar macrophages in vitro. However, this does not exclude an indirect effect in vivo. The results contrast with previous studies on animal alveolar macrophages.