Tannin Inhibits cAMP Pathways in Airway Epithelial Cells (AEC)

Michelle M. Cloutier, Linda Guernsey


Tannin inhibits cAMP production in bovine AEC in part by inhibiting adrenergic receptor binding. The purpose of this study was to determine whether tannin affected other parts of the adrenergic-cAMP signal transduction pathway by examining the effect of tannin on GTP-regulatory (G) proteins. cAMP production in confluent AEC was measured in the presence of forskolin, a direct activator of adenylate cyclase, pertussis toxin, an inhibitor of Gi proteins and cholera toxin, an activator of Gs proteins. In cells pretreated with 50 g/ml tannin, forskolin-stimulated cAMP production was reduced to basal levels while pertussis toxin cAMP levels were unaffected. cAMP levels were diminished in cells pretreated with 50 g/ml tannin followed by cholera toxin stimulation. We conclude that tannin inhibits the production of cAMP in AEC by direct effects upon adenylate cyclase or by possibly altering G protein regulation.

Reprinted from Proceedings of the 1994 Beltwide Cotton Conferences pp. 326 - 328
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998