l-Canavanine inhibits l-arginine uptake by broiler chicken intestinal brush border membrane vesicles

Abstract

1. Intestinal brush border membrane vesicles (BBMV) were prepared from 3-week-old broiler chickens. 2. Electron microscopy of the BBMV fraction showed single membrane vesicles of different sizes with no electron dense material inside. No other organelles were observed. The sucrase and maltase activities were enriched by factors of 16 and 18, respectively, in the BBMV fraction in comparison with the homogenate. On the other hand, the Na⁺/K⁺-ATPase sensitivity to ouabain was increased by a factor of 0·8. 3. The BBMV showed a maximum l-[¹⁴C]-arginine uptake (944·9 ± 22·9 pmoles/mg protein) at 45 s and thereafter it declined slowly. In the presence of 0·5 mm l-canavanine, the l-[¹⁴C]-arginine uptake by BBMV was reduced by 43·6% at 45 s. 4. It is concluded that l-canavanine inhibits l-arginine Na⁺-dependent transport across the enterocyte apical membrane in a highly purified intestinal BBMV from broiler chickens.