fourth , prostaglandin e1 and the inhibitors of the cyclic nucleotide phosphodiesterases , 3-isobutyl-1-methylxanthine , theophylline , and caffeine , all increased both cellular camp and cgmp concentration but had no effect on 2-dg uptake .
C0000096
3-isobutyl-1-methylxanthine
C0039771
theophylline