Objective   To discuss the effect of supplement L-arginine on concentration of nitric oxide(NO)in serum and lymphocyte proliferation under heat stress.

  Methods   Male BALB/C mice are div ided randomly into a water supplement group, four groups 0.5, 1.5, 2.5, 3.5 g/(kg·bw)of L-Arg, each with 35 mice, normal temperature contrast group with 5 ones.After 14 days, all the mice are treated with heat stress(41±0.5) ℃, 120 minexpect for normal temper ature contrast group.After heat stress, round-the-clock every two hours, get blood from eye so cket separately and tail for the mice of normal temperature contrast group at 3, 7, 11, 14 days.To obverse index and determine the content of the NO in serum and the cell activity of the miceslympho poiesis.

  Results   Under the normal temperature, the content of the NO in serum reaches maximum after three days of the arginine supplement, and reaches stabilization 7 days later, groups at any time is higher in the supplement than not supplement groups, and the group of 0.5 g/(kg·bw)is the most in all supplement groups.Under the heat stress, the content of the NO in serum decreases first and increases later in these groups of the 0.5, 1.5 g/(kg·bw)and not supplement group.After 4-8 h, it reaches stabilization.However, in high content groups 2.5 and 3.5 g/(kg·bw), NO rises steadily after high stress, and dur ing the 12 h, the content of NO is hig her than the former ones.Under heat stress, con canavalin A(ConA)stimulation exponent in the supplement group is higher than compared groups.In all supplement groups, ConA stimulat ion exponent of the 1.5 g/(kg·bw)group reach the most.After heat stress, the cell activity of the little mouses lymphopoiesis is restrained, and during 4 to 8 h, it reaches minimum.

  Conclusion   The mouse requires more arginine in heat stress, but the changes of NO in serum concerns with the arg inine suse.Lymphopoiesis depends on the adjustment of moder ate NO in serum.More arginine supplenents product excess NO and restrain the multiplication of the cells.