Single bout of endurance exercise increases NNMT activity in the liver and MNA concentration in plasma; the role of IL-6

Background: methylnicotinamide (mna) displays vasoprotective activity,however,the regulation of the activity of nicotinamide- n-methyltransferase (nnmt),is largely unknown. we analyze a possible involvement of il-6 in the activation of nnmt-mna pathway during an endurance exercise. methods: fvb,c57bl/6j il6+/+ and c57bl/6j il-6-/- mice were subjected to the single bout of endurance exercise consisting of 90 min of swimming. thereafter,exercise-induced changes in nnmtactivity in the liver as well as concomitant changes in the concentration of mna and its further metabolites in plasma were analyzed. results: in two strains of mice (fvb and c57bl/6j il6 +/+) 90 min of swimming resulted in approximately 2-3 folds increase in nnmt activity (from 0.14 ± 0.03 to 0.421 ± 0.02 pmol/min/mg,p < 0.05 and from 0.2 ± 0.06 to 0.35 ± 0.07 pmol/min/mg,p < 0.01,respectively) and concomitant increase in the plasma concentration of mna (from 157 ± 15.06 to 230 ± 16.2 ng/ml,p < 0.01,and from 77.05 ± 14.6 ng/ml to 152.55 ± 58.4 ng/ml; p < 0.01,respectively). however,in c57bl/6j il-6-/- mice 90 min of swimming did not change liver nnmt activity (from 0.25 ± 0.07 to 0.23 ± 0.06 pmol/min/mg),while mna concentration in plasma rose approximately two-fold (from 65.3 ± 30.9 ng/ml to 124.8 ± 35.8 ng/ml; p < 0.05). conclusions: we demonstrated for the first time that nnmt - mna pathway is activated by a single bout of endurance exercise. interestingly,exercise-induced activation of nnmt in the liver involves il-6,while the rise in mnaconcentration in plasma was partially il-6-independent. taking into the consideration the pharmacological activity of mna,il-6-dependent and il-6-independent activation of nnmt,may contribute to the exercise capacity. the physiological role of nnmt in the exercise warrant further studies. copyright © 2012 by institute of pharmacology polish academy of sciences.