Influence of alpha-linked glucose on jejunal sodium-glucose co-transport activity in ruminants.
Eight steers and 12 lambs were used in a completely randomized experimental design to determine the effect of partial alpha-amylase starch hydrolysate (SH) on small intestinal sodium-dependent glucose transport activity. Starch hydrolysate was delivered ruminally or abomasally to steers (960 g/day) and sheep (144 g/day) for 7 days. On day 7, the steers were rendered unconscious, exsanguinated and eviscerated. A 1-m section of jejunum was collected starting at the duodenojejunal flexure. Sheep were anaesthetized with pentobarbital and the second meter of small intestine (jejunum) was collected. Brush-border membrane vesicles were prepared and sodium-dependent glucose uptake activity was measured using the rapid uptake/filtration technique. Alkaline phosphatase and maltase activity was enriched by 8.2+/-0.5- and 8.4+/-1.2-fold in the vesicle preparation, respectively, and was not different between treatments. Abomasal SH increased (P=0.03) the Na/glucose co-transport approximately two-fold in both cattle (47.2-114.0+/-31.5 pmol/mgxsec) and sheep (77.4-152.0+/-25.7 pmol mg(-1) s(-1)). We conclude that Na/glucose co-transport activity by enterocytes responds to luminal alpha-linked glucose (from abomasal infusion) in ruminants, compared with controls. Intestinal maltase-specific activity does not respond to alpha-linked glucose in cattle, and decreases slightly in sheep.
Bauer
M L
ML
Department of Animal Sciences, University of Kentucky, Lexington, KY 40546-0215, USA.
Harmon
D L
DL
McLeod
K R
KR
Huntington
G B
GB
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D002417:Cattle; D005947:Glucose / Q000378:metabolism*; D006868:Hydrolysis; D007583:Jejunum / Q000378:metabolism*; D008297:Male; D008871:Microvilli / Q000378:metabolism; D012418:Ruminants / Q000502:physiology*; D012756:Sheep; D012964:Sodium / Q000378:metabolism*; D013213:Starch / Q000737:chemistry / Q000494:pharmacology*; D000516:alpha-Amylases / Q000737:chemistry / Q000378:metabolism; D000520:alpha-Glucosidases / Q000378:metabolism
D013213:Starch; D012964:Sodium; D000469:Alkaline Phosphatase; D000516:alpha-Amylases; D000520:alpha-Glucosidases; D005947:Glucose