α1-Adrenergic stimulation of ketogenesis and fatty acid oxidation is associated with inhibition of lipogenesis in rat hepatocytes

Publisher Website
Google Scholar
Abstract
The effect of norepinephrine on fatty acid synthesis (3H2O incorporation into fatty acids), on fatty acid oxidation to CO2 and on ketogenesis was studied in isolated hepatocytes of fed rats. After incubation with norepinephrine (50 μM), lipogenesis was lower (5.7±1.1 nmoles3H2O incorporated into fatty acids/mg dry weight/30 min) than in controls (7.5±1.7; n=6, p14C) palmitate conversion into total ketone bodies was increased to 10.9±1.8 nmoles/mg/30 min with norepinephrine, vs 8.5±1.6 in controls (p14C) palmitate was converted to14CO2 with norepinephrine than in controls (1.48±0.10 nmoles/mg/30 min vs 1.06±0.11, p1-receptor blocker prazosin, but not by α2 or β-blockers. The results demonstrate that the ketogenic effect of norepinephrine is coupled with an inhibitory effect on lipogenesis which may be explained by diminished activity of acetyl-CoA carboxylase, diminished formation of malonyl-CoA and decreased activity of carnitine palmitoyl transferase I.