J Gastroenterol 2001; 36:407–409 Short communication Activity of brush border membrane enzymes in proximal jejunum of portal hypertensive rats Upjeet Kaur 1 , Simran Kaur 1 , Akhtar Mahmood 2 , and Navneet Agnihotri 1 1 Department of Experimental Medicine and Biotechnology, PGIMER, Chandigarh 160012, India 2 Department of Biochemistry, Panjab University, Chandigarh, India pathy in 84% of portal hypertensive patients. Con- gestive jejunopathy was defined by the presence of ectatic capillaries and venules in the villi, with an in- crease in the number of vessels. Our own observations revealed clubbing and blunting of villi, in addition to vascular congestion in the jejunum. 8 The effect of these changes in gastrointestinal morphology on function is not clearly established. Thus, although malnutrition is commonly observed in patients with chronic liver dis- ease and portal hypertension, 6,12 only some alterations in absorptive function have been described in vivo. 13–17 More recently, Hayashi and coworkers 18 demonstrated sugar malabsorption in rats with suprahepatic portal hypertension, although Romiti et al. 19 could demon- strate only fat malabsorption in cirrhotic patients. An earlier study had shown decreased activity of alkaline phosphatase, aminopeptidase, acid phosphatase, and succinic dehydrogenase in carbon tetrachloride-induced experimental cirrhosis in rats. 20 In the present study, we made an attempt to measure the activity of brush border membrane enzymes and to compare this activity in extrahepatic and intrahepatic portal hypertension models. Wistar rats of either sex, weighing 125–200 g, were used for the study. Extrahepatic portal hypertension was produced by partial portal vein ligation (PPVL), 21 and intrahepatic portal hypertension was produced by common bile duct ligation (CBDL). 22 In both groups, portal hypertension was confirmed by the measurement of intrasplenic pulp pressure. 23 Sham-operated animals were used as controls for both groups. Animals were killed 25–28 days after PPVL and 18 days after CBDL, and the small intestine was removed, washed with saline, and stored at -20°C. A homogenate of the intes- tines was prepared, and the biochemical parameters studied. The activities of sucrase and lactase were deter- mined by measuring d-glucose liberated from the respective sugar, using the glucose oxidase peroxidase method. 24 Alkaline phosphatase was measured by the Received: August 16, 2000 / Accepted: January 19, 2001 Reprint requests to: U. Kaur Purpose. Malabsorption accompanies portal hyper- tension, especially when associated with chronic liver disease. The development of portal hypertension is accompanied by significant alterations in the splanchnic microcirculation. In this study, the effect of extrahepatic and intrahepatic portal hypertension on brush border membrane enzymes was estimated. Methods. Portal hypertension was induced in rats by partial portal vein ligation (PPVL) (n = 6) and common bile duct ligation (CBDL) (n = 6), and the activity of sucrase, lactase, alkaline phosphatase, and leucine aminopeptidase (LAP) in the intestinal homogenate was measured. Re- sults. Intrasplenic pulp pressure (ISPP) (in cm of saline) was found to be elevated in PPVL (21.3  1.47) and CBDL animals (21.5  1.79) as compared with findings in their respective sham-operated controls (12.74  0.86, 11.83  1.04). Only sucrase and LAP activity was significantly elevated (P  0.05) in the PPVL group. No changes were observed in the CBDL group. Con- clusion. Only sucrase and LAP activities were increased in PPVL rats. Key words: experimental portal hypertension, brush border membrane enzymes, lactase, sucrase, alkaline phosphatase, leucine aminopeptidase Chronic portal hypertension has been shown to be asso- ciated with marked alterations in the gastrointestinal microcirculation, gastric mucosa, and small intestinal transit. 1–6 Gastrointestinal tract involvement in portal hypertension includes the formation of esophageal varices, gastropathy, 7,8 enteropathy, 9 and colopathy. 10 Nagral and coworkers 11 reported congestive jejuno-