LIPOCORTIN-1 DISTRIBUTION IN BRONCHOALVEOLAR LAVAGE FROM HEALTHY-HUMAN LUNG - EFFECT OF PREDNISOLONE

Lipocortin-1 (LC-1; annexin-1) may mediate some anti-inflammatory acti ons of the glucocorticoids, probably after binding to specific cell su rface binding sites. We have quantified LC-1 levels in bronchoalveolar lavage (BAL) fluid and cells collected from seven healthy volunteers before and after 7 days of treatment with an oral glucocorticoid, pred nisolone (30 mg/day). Extracellular BAL LC-1 was higher and cellular L C-1 was lower after prednisolone than before [extracellular: before, m edian 98 ng/mg albumin (range 48-350 ng/mg albumin); after, 236 ng/mg albumin (19-414 ng/mg albumin); P < 0.05. Cellular: before, 23.3 ng/10 (6) cells (14.6-26.9 ng/10(6) cells); after, 18.0 ng/10(6) cells (122- 268 ng/10(6) cells); P < 0.05]. The distribution of LC-1 within BAL ce lls ex vivo (cell surface = 25%, cytosol = 50%, membrane = 25%) was un affected by prednisolone treatment. However, in adherent cells that ha d been cultured for 4 h, 70-80% of the LC-1 was on the cell surface. I n summary, prednisolone appears to promote cellular release of LC-1. T he difference in distribution of cellular LC-1 in BAL cells ex vivo an d in vitro may reflect adherence and/or activation.