Sodium-dependent D-glucose transport in brush-border membrane vesicles after massive distal small bowel resection in the rat.
Massive small intestinal resection in the rat results in both structural and functional changes in the residual small bowel. Sodium-dependent D-glucose transport was examined in brush-border membrane vesicles derived from the proximal small bowel mucosa of male Sprague-Dawley rats 2 and 6 wk after a 66% distal jejunoileal resection or jejunoileal transection. Kinetic characteristics for the low-affinity, high-capacity system and high-affinity, low-capacity system were defined with rapid filtration under conditions of a zero-trans, 100 mM cis-NaSCN gradient. Mucosal weight, protein, and deoxyribonucleic acid content were increased in the residual intestinal segment compared to transected controls and morphometric studies revealed increased villus and crypt heights as well as an increased mitotic index. Postresection mean kinetic parameters for D-glucose transport at 2 wk (low-affinity system: Km, 177.5 +/- 45.1 microM; Vmax, 3.73 +/- 0.99 nmol X mg protein-1 X min-1; and high-affinity system: Km, 6.2 +/- 1.9 microM; Vmax, 0.12 +/- 0.06 nmol X mg protein-1 X min-1) and 6 wk (low-affinity system: Km, 267.8 +/- 83.1 microM; Vmax, 0.06 +/- 0.01 nmol X mg protein-1 X min-1; and high-affinity system: Km, 6.5 +/- 1.1 microM; Vmax, 0.06 +/- 0.01 nmol X mg protein-1 X min-1) were similar to values post-transection at 2 wk (low-affinity system: Km, 280.4 +/- 53.7 microM; Vmax, 3.05 +/- 0.32 nmol X mg protein-1 X min-1; and high-affinity system: Km, 9.1 +/- 1.3 microM; Vmax, 0.17 +/- 0.01 nmol X mg protein-1 X min-1) and 6 wk (low-affinity system: Km, 271.7 +/- 17.5 microM; Vmax, 4.69 +/- 0.23 nmol X protein-1 X min-1; and high-affinity system: Km, 10.6 +/- 4.2 microM; Vmax, 0.16 +/- 0.09 nmol X mg protein-1 X min-1). These kinetic data suggest that the hyperplastic response in adapting proximal small bowel after distal resection is accompanied by a persistence of the membrane functional characteristics for both sodium-dependent D-glucose transport systems despite an altered pattern of enterocyte proliferation and differentiation.
D000818:Animals; D001692:Biological Transport; D001835:Body Weight; D005947:Glucose / Q000378:metabolism*; D006965:Hyperplasia; D007421:Intestine, Small / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure; D007700:Kinetics; D008297:Male; D008871:Microvilli / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000494:pharmacology*
D012964:Sodium; D005947:Glucose