FIG. 4.

Effect of l-arginine injection on peritoneal T. b. brucei count and NO₂⁻ concentration. HBSS (0.5 ml), alone or containing l-arginine (0.1 M), d-arginine (0.1 M), or l-arginine (0.1 M) plus l-NA (0.1 M), was intraperitoneally injected into 10-day-infected mice (i.e., the quantity injected per mouse was 8.7 mg of l-arginine or d-arginine or 10.9 mg of l-NA). After 24 h, peritoneal content was gathered by injecting 4 ml of HBSS. Parasites were then counted (open bars). After centrifugation at 1,500 × g, NO₂⁻ concentrations were assayed in each supernatant (gray bars). Each result represents the mean ± standard error from six animals.