Abstract
Epinephrine and other compounds containing a 3,4-dihydroxyphenylethyl backbone were found to be noncompetitive inhibitors of a cyclic nucleotide phosphodiesterase isolated from beef heart. The structural requirements for this inhibition were different from those of classical alpha or beta adrenergic receptors, and inhibition was not prevented by the addition of adrenergic blockers. At a cyclic AMP concentration of 1.0 mM, epinephrine was a more potent inhibitor than theophylline. The concentration required for half-maximal inhibition was 7 µM. In the presence of a low substrate concentration (0.01 mM), however, it was less potent than either theophylline or papaverine. Elucidation of the basic structural requirements for inhibition by this group of compounds may aid in the design of more potent and specific cyclic nucleotide phosphodiesterase inhibitors.
ACKNOWLEDGMENT The authors wish to thank Mr. Allen Hirsch for his excellent technical assistance.
- Copyright ©, 1972, by Academic Press, Inc.
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