Studies on 3, 7-Dimethyl-1-(5-oxo-hexyl)-xanthine (BL 191). II. Effect of BL 191 on Lipolysis in Rat Epididymal Adipose Tissue

抄録

Effects of 3, 7-dimethyl-1-(5-oxo-hexyl)-xanthine (BL 191) on lipolysis in rat epididymal adipose tissue were investigated by comparison with those of theophylline. BL 191 blocked the activity of phosphodiesterase in the 105000×g supernatant prepared from rat epididymal adipose tissue, and the type of inhibition was noncompetitive with the K_i value of 2.1mM. Furthermore, BL 191 elicited a dose-dependent lipolytic response, as did theophylline, and the response increased 1, 3-fold and about 3-fold over the basal activity at 2mM and 5mM, respectively. BL 191 as well as theophylline potentiated the lipolytic action of epinephrine and increased adenosine 3', 5'-monophosphate (cyclic 3', 5'-AMP) levels in adipose tissue. BL 191, in a concentration producing no effects by itself (10^-4M), together with epinephrine (10^-6M) caused a 38-fold increase in cyclic 3', 5'-AMP levels and an about 5-fold increase in lipolytic effecs.