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Acceleration of the degradation of tyrosine aminotransferase in rat hepatoma (HTC) cells by inhibitors of cyclic nucleotide phosphodiesterase

1977; Elsevier BV; Volume: 78; Issue: 4 Linguagem: Inglês

10.1016/0006-291x(77)91415-2

1090-2104

Robert H. Stellwagen, Rochelle D. Sailor, Kulwant K. Kohli,

Receptor Mechanisms and Signaling

Abstract The following inhibitors of cyclic nucleotide phosphodiesterase reduce the specific activity of tyrosine aminotransferase when added to cultures of rat hepatoma (HTC) cells: theophylline, 1-methyl-3-isobutylxanthine, 4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone, and papaverine. Immunochemical measurements show that each inhibitor reduces the rate of tyrosine aminotransferase synthesis and increases the rate of degradation of the enzyme. The effect on synthesis also occurs with general proteins while that on degradation appears specific for tyrosine aminotransferase.