Intestinal sugar transport during ageing.
Ageing effects on sugar intestinal transport were studied by using the everted sac and the brush-border membrane vesicle techniques. Four age groups of rats were used: very young, young, adult and old animals. Net transintestinal transport of D-glucose and intracellular sugar accumulation were greater in young than in very young, adult and old rats. Net Na+ transport was high in very young and young animals and then it declined with age. In brush-border membrane vesicle experiments D-glucose overshoot was smaller in the groups of animals where net sugar transport was less. In old rats, however, the overshoot did not occur. Short-circuiting of vesicles with valinomycin showed that the driving forces for sugar accumulation, i.e. the chemical potential gradient of Na+ and the electrical potential gradient, played different roles during ageing. In very young animals the chemical potential gradient seems to be responsible for D-glucose overshoot; in young rats both gradients are important while in adult animals the electrical potential gradient represents the main driving force.
D000375:Aging; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D050260:Carbohydrate Metabolism; D005947:Glucose / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000648:ultrastructure; D008871:Microvilli / Q000378:metabolism; D051381:Rats; D012964:Sodium / Q000378:metabolism; D013997:Time Factors; D014634:Valinomycin / Q000494:pharmacology
D014634:Valinomycin; D012964:Sodium; D005947:Glucose