he aim of this study is to investigate the change of NOS of gastric muosa in duodenl ucler (30 cases)and non-ulcer dyspepsia(12 cues)serving as control.In each subject. totally 5 specimens were obtained from the gastric antrum and body

for the examination of Helicobacter pylori(HP)and determination of NOS activity.All DU patients received the treatment consisting of 2-wk course of tripotassium dicitroto-bismuthate(TDB) 100mg tid tetracyclin 250mg tid

and metronidazole 200mg tid. The ulcer healing and HP eradication were confirmed by follow- up endoscopy with biopsies 4 wk after the completion of therapy.Results:Gastric mucosa NOS activity in 30 DU was 83.6±12.5U in antrum and 78.6±16.5U in body

highe. than that of 12 controls in

gastric antrum(51±8.8U) and body(4.2 ±8.2U) respectively(P< 0 .05).In 27 cases of HP positive DU: . gastric antrum NOS activity was 85.1±12.1U

which was higher than that of gastric antrum in 6 HP positive controls. (52.7 ±3.1U)(P<0.05).In 28 cases of cured DU . NOS activity of gastric mucosa was markedly lower than that of its corresponding activity before treatment (P< 0. 05)and approximately to its activity of the controls. These findings suggest that in DU patients there are enhencement of gastric mucosa NOS activity

which may have a role in the . pathoensis of the disease .Our preliminary results suggest that the gastric mucosa NOS activity is irrelevant to HP infection.