Figure 2. Effects of spexin on the motor activity of gastrointestinal tract in mice in vivo.

(A) Expression level of spexin mRNA in intestine and colon of mice under the starvation condition. Mice were starved for 24 hours and then the total RNA of proximal colon, distal colon, jejunum and ileum were prepared for real-time PCR of spexin mRNA. (B) Effect of intraperitoneal (ip) spexin on propulsion of the carbon powder in the intestine. Saline or spexin (300 μg/kg and 1000 μg/kg) was injected ip and mice were placed in individual cages without water and food for 20 minutes. Then 0.2 ml 10% powdered carbon suspended in 5% gum arabic was intragastric administered. 15 minutes later, the mice were sacrificed and the distance of carbon-ink from the pylorus to the most distal point of the charcoal was recorded. (C) Effect of spexin (ip injection) on the efflux time of glass beads in the colon. A single 3-mm colored plastic bead was inserted into the distal colon (2.5 cm past the anus) with a lubricated plastic rod and then saline or spexin (300 μg/kg and 1000 μg/kg, respectively) were administrated by ip injection. The expulsion time of the bead for each mice was monitored. Statistical differences between individual groups were evaluated using One way ANOVA. *P < 0.05 and **P < 0.01 compared with paired saline-treated controls.