RESUMO
BACKGROUND: In the 13C-octanoate breath test, the shape of the 13CO2 excretion curve in the ascending portion reflects a pattern of gastric emptying (GE). Recent scintigraphic studies have revealed an overall delay in solid GE in fertile women compared with men. However, it remains unknown whether women have a different GE pattern compared with men. As a symptomatic delay in solid GE is specific to the female gender, it could be hypothesized that the 13CO2 excretion curve is different in shape between genders. MATERIALS AND METHODS: Because the ascending gradient of the 13CO2 excretion curve is often biphasic, the dual function of y(t) = ( a1 . tb1 + a2 . tb2) e(-K.t) was applied to fit the breath data, where a1, b1, a2, b2, and K are constants. Assessed on the 4 h-based breath samples obtained after ingestion of a 320-kcal muffin containing 100 mg 13C-octanoate, the time versus 13CO2 excretion curve was created from 31 adult volunteers (15 men and 16 women). The curve shape was characterized by the dual function, and was compared between genders. RESULTS: In both genders, the ascending gradient exhibited the biphasic feature, characterized by an initial steep rise and the subsequent blunted increase, while the descending gradient followed the monotonous decay. The initial rise was steeper and the subsequent increase was more blunted in women than in men. CONCLUSION: Women exhibit a gender-specific pattern of the 13CO2 excretion profile. A possible explanation for this gender difference is that the post-gastric feedback regulation is more potent in women than in men.