THE EFFECTS OF CORTICOSTEROIDS ON MUCOUS GLYCOPROTEIN-SECRETION FROM HUMAN AIRWAYS INVITRO

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Abstract
To examine the mechanisms by which corticosteroids may benefit some patients with bronchorrhea, cultured human airways releasing [3H]glucosamine-labeled mucous glycoproteins were exposed to corticosteroids, and mucus release was examined. Both dexamethasone and methylprednisolone produced dose-related suppression of the spontaneous release of radiolabeled mucous glycoproteins. Inhibitory effects of dexamethasone were maximal after 18-24 h and returned to control levels by 34 h. To study the effects of dexamethasone on stimulated mucus release, airways were exposed to dexamethasone and to the mucus secretagogues, histamines or 5-monohydroxyeicosatetraenoic acid. Both secretagogues stimulated radiolabeled mucous glycoprotein release from airways that had never been exposed to corticosteroids, and in a reduced fashion from corticosteroid-treated airways. The reduced mucus release caused by secretagogues from dexamethasone-treated airways appeared to reflect a lowered baseline secretion rate rather than a specific inhibition of either secretagogue.