CHARACTERIZATION OF ADENYLATE-CYCLASE ACTIVITY IN BOVINE AND HUMAN CORNEAL EPITHELIUM

  • 1 January 1980
    • journal article
    • research article
    • Vol. 19  (9) , 1080-1086
Abstract
The properties of adenylate cyclase from bovine and human corneal epithelium were investigated. Adrenergic drugs were the most effective stimulatory agents tested in bovine tissue, causing greater activation than Fl-. Isoproterenol was the most potent agonist, followed by epinephrine and norepinephrine. Phenylephrine and dopamine stimulated adenylate cyclase through .beta.-adrenergic receptors at relatively high concentrations. Enzyme stimulation by all the adrenergic drugs tested was completely inhibited by 1 .mu.M propranolol or 0.1 .mu.M timolol. The GTP analog, GppNp, produced considerable activation and caused an augmented response when combined with isoproterenol, but not with Fl. Prostaglandins E1, E2 or F2.alpha. produced a small but significant stimulation over control which was not sensitive to propranolol inhibition. Adenylate cyclase from human corneal epithelium exhibited qualitatively similar characteristics to those of the bovine enzyme. Fl- was the most effective stimulatory agent, followed by isoproterenol, phenylephrine and dopamine. Prostaglandins failed to stimulate adenylate cyclase activity in human corneal epithelial preparations.

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