OBJECTIVE:To investigate the first-pass effect and mechanism of vitexin-4′-O-glucoside(VG)in rats so as to pro-vide a basis for new drug development. METHODS:10 SD rats were divided into a group of hepatic portal venous administration and a group of femoral venous administration,which respectively received VG iv at superior mesenteric vein and femoral vein,and then metabolic rate was calculated by finding out the AUC of VG in the rats’livers. 15 SD rats were divided into a group of gastric infusion,a group of intestinal infusion and a group of hepatic portal venous infusion,which respectively received VG by infusion at gastric fundus and duodenum and iv at superior mesenteric vein,and then metabolic rate was calculated by finding out the AUC of VG in the rats’stomachs and intestines. 15 SD rats were divided into a group of intestinal infusion,a group of femoral venous administration and a group of normal saline. At 10 min before administration,the former two groups were given by infusion vera-pamil injection(60 ml/kg),the substrate of CYP3A and P-glycoprotein(P-gp);and the group of normal saline were given by infu-sion of isometric normal saline,and then the rats were given VG as above to observe the effect of verapamil on intestinal absorp-tion of VG. RESULTS:The metabolic rates of VG in the liver,stomach and intestine were 54.9%,1.7% and 91.9% respectively. After infusion of verapamil,slight increase in AUC of VG was found in the rats in the group of intestinal infusion. CONCLU-SIONS:The first-pass effects in the liver and intestine are the main factors related to the low bioavailability of VG. Based on pre-liminary judgment,VG is the substrate of intestinal CYP3A and/or P-gp.

AIM: To observe the expressions of aquaporin 2 (AQP2) in kidney tissues and the contents of endotoxin (ET), interleukin-1 β (IL-1β), tumor necrosis factor-α (TNF-α) in serum in emphysema model rats, and to investigate the relationship between lungs and kidney in humoral metabolism. METHODS: The rats of emphysema were treated by injecting lipopolysaccharide into the trachea with cigarette smoking. Immunohistochemistry and Western blotting analysis were used to observe the expression of AQP2 in kidney tissues. RT-PCR was applied to detect the expression of AQP2 mRNA in kidney tissues. Blood sample and lung tissue were taken and the levels of ET, IL-1β and TNF-α were measured by radioimmunoassay. RESULTS: AQP2 expression in the kidney tissue in model group was greater than that in control group, and the expression of AQP2 mRNA showed the same results (P<0.01). ET, IL-1β and TNF-α levels in serum and lung tissue in model group were markedly higher than those in control group (P<0.01). CONCLUSION: In the emphysema model rats, AQP2 expression is up-regulated in the kidney tissue. The mechanism of emphysema may be related to increasing the levels of ET, IL-1β and TNF-α in the serum and lung tissue obviously.