Taurocholate transport by brush border membrane vesicles from different regions of chicken intestine

Abstract

Taurocholate transport was studied in brush border membrane vesicles (BBMV) isolated from chicken small (duodenum, jejunum, and ileum) and large (proximal cecum and rectum) intestines, using a rapid filtration technique. The purity of the BBMV was verified by the finding that the specific activity of sucrase (a brush border membrane enzyme marker) was severalfold greater in vesicles than corresponding values in mucosal homogenate. The functional integrity of isolated BBMV was evaluated by the uptake of D-glucose, which showed a transient increase in the presence of Na+. A Na+-dependence of taurocholate uptake was shown in BBMV prepared from ileum, cecum, and rectum, as taurocholate transport was transiently increased (accumulation) in the presence of a Na+ gradient between the external medium and intravesicular medium. The magnitude of the accumulation was similar among ileum, cecum, and rectum. In contrast, BBMV prepared from duodenum and jejunum did not show any Na+-dependent taurocholate transport, as the taurocholate uptake was not affected when a Na+ gradient was replaced by a K+ gradient. The use of taurochenodeoxycholate in the incubation medium inhibited Na+-dependent taurocholate transport in the ileum, cecum, and rectum. This study is the first to show the presence of a Na+-dependent bile salt transport in BBMV obtained from chicken ileum, proximal cecum, and rectum.

Potential Impact of Nutritional Strategy on Noninvasive Measurements of Hormones in Birds

“…In other species (e.g., ducks), bile produced in the left side of the liver can reach the gall bladder via a common sinus. Chickens,25 pigeons,26 and presumably all birds possess an efficient enterohepatic circulation that recovers bile acids and other sterols by active transport in distal areas of the small intestine 27. Resorbed bile acids enter the portal vein and are returned to the liver where they are secreted again.…”

Epithelial cell polarity as reflected in enterocytes

“…On the other hand, maximum levels of taurocholate transport occur in the ileum (Coleto et al, 1998), where the receptor for the vitamin B12 intrinsic factor complex is also located (Hagedorn and Alpers, 1977). Studies involving the subcellular fractionation of enterocytes and the purification of various plasma membrane domain components have shown that the functional specificity of the absorbing cells along the intestine results from the presence of various enzymes and transporters in the BB and basolateral domains.…”

Proteomic Evaluation of Chicken Brush-Border Membrane during the Early Posthatch Period

“…Brush-border membrane isolation was performed as previously described, based on modification of several protocols. − Frozen tissue was added to ice-cold homogenization buffer (100 mM mannitol, 2 mM HEPES/Tris pH 7.4, 0.1 mM phenylmethylsulfonyl fluoride (PMSF)) and homogenized at full speed for four 30 s periods, and buffer was added to achieve a 5% homogenate. The HEPES was biotech grade (Sigma Aldrich; St. Louis, MO) and PMSF was purchased from Pierce.…”