Possible mechanisms of the inhibiting effect of nicotinamide on lipogenesis in rat liver
Mogilevich, S.E.; Velikiĭ, N.N.; Khalmurodov, A.G.
Biokhimiia 46(1): 103-109
1981
ISSN/ISBN: 0320-9725 PMID: 6454446 Document Number: 181288
The activity of some NAD- and NADP-dependent dehydrogenases involved in generation of the reducing equivalents for lipogenesis and the activity and some kinetic parameters of ATP-citrate (pro-3S)-lyase from rat liver, i.e., the enzyme involved in the formation of acetyl-CoA, the primary substrate of fatty acid biosynthesis, were studied. The changes in the activity of NADP-dependent dehydrogenase and ATP-citrate (pro-3S)-lyase, as well as the affinity of the latter for citrate and CoA, and the rate of lipogenesis in starved rats and in rats kept on a carbohydrate-rich diet after starvation appeared to be parallel. Nicotinamide decreased the activity of all NADP-dependent dehydrogenases under study, which was especially well-pronounced after nicotinamide addition against increased lipogenesis. The affinity of ATP-citrate (pro-3S)-lyase for citrate and CoA decreased simultaneously with the decrease in the concentration of the latter. These changes can possibly induce the decrease of the lipogenesis rate in rat liver after addition of nicotinamide.