1. Department of Pharmacology and Medicine (Hematology and Oncology), Emory University School of Medicine, Atlanta, Ga. 30322, USA;1. Department of Biochemistry, Howard University College of Medicine, Washington, D.C. 20059, U.S.A.
Abstract:
Modifications in the cyclic nucleotide systems favoring the expression of cyclic GMP effects were found to occur in the transplanted fast-growing Morris hepatoma 3924A. These included: (a) a decreased level of cyclic GMP phosphodiesterase and an increased level of cyclic AMP phosphodiesterase; (b) a disproportionately increased level of cyclic GMP-dependent protein kinase relative to that of cyclic AMP-dependent protein kinase; (c) a disproportionately increased level of stimulatory modulator of cyclic GMP-dependent protein kinase relative to that of inhibitory modulator of cyclic AMP-dependent protein kinase; and (d) an increased level of phosphoprotein phosphatase.