Net transintestinal transport of D-glucose (Gl) and 3-0-methyl-D-glucose (3MG) in four classes of rats (very young, young, adult and old) was studied both “in vitro” and “in vivo”. D-glucose uptakes into brush border membrane vesicles (BBMV) were also determined. “In vitro” experiments were performed on everted sac of jejunum and on BBMV by using a rapid filtration technique. “In vivo” studies were carried out on the same intestinal tract perfused “in situ”. The main results obtained were the following: i) “in vitro” net transintestinal transport of Gl was higher in young rats than in very young and adult animals but much lower in aged rats. Gl uptake into BBMV showed the same pattern. The presence of valinomycin reduced Gl uptake in young animals and abolished it in adult rats. Surprisingly, old animals did not show any overshoot in both control and valinomycin-treated vesicles. ii) Net transintestinal 3MG transport “in vitro” was similar in the first three groups of animals and decreased only in old rats. iii) “In vivo” experiments showed a similar transport of 3MG in all groups of animals but a reduced transport of Gl only in aged animals. The volume of the enterocytes of old rats was consistently lower both in “in vitro” and “in vivo” experiments. Valinomycin studies indicated that the electrical properties of BBMV affected sugar uptake differently in the various ages of animals. Moreover, it seemed that old rats did not present a Na+-dependent uptake since there was no overshoot and the pattern of Gl uptake was similar when Na+ or K+ were present in the incubation medium. “In vivo” experiments showed a decreased transport of Gl only in old rats. This seems to indicate that in “in vivo” conditions other factors can influence Gl transport since this sugar, unlike 3MG, showed different transport rates in the four groups of animals during “in vitro” studies.

Intestinal absorption of carbohydrates / G. Esposito, M. Tosco, C. Lindi, M.N. Orsenigo, P. Marciani, G. Monticelli, A. Faelli. ((Intervento presentato al 47. convegno Falk Symposium - Aging in Liver and Gastrointestinal Tract tenutosi a Titisee nel 1987.

Intestinal absorption of carbohydrates

M. Tosco
Secondo
;
C. Lindi;M.N. Orsenigo;P. Marciani;G. Monticelli
Penultimo
;
A. Faelli
Ultimo
1987

Abstract

Net transintestinal transport of D-glucose (Gl) and 3-0-methyl-D-glucose (3MG) in four classes of rats (very young, young, adult and old) was studied both “in vitro” and “in vivo”. D-glucose uptakes into brush border membrane vesicles (BBMV) were also determined. “In vitro” experiments were performed on everted sac of jejunum and on BBMV by using a rapid filtration technique. “In vivo” studies were carried out on the same intestinal tract perfused “in situ”. The main results obtained were the following: i) “in vitro” net transintestinal transport of Gl was higher in young rats than in very young and adult animals but much lower in aged rats. Gl uptake into BBMV showed the same pattern. The presence of valinomycin reduced Gl uptake in young animals and abolished it in adult rats. Surprisingly, old animals did not show any overshoot in both control and valinomycin-treated vesicles. ii) Net transintestinal 3MG transport “in vitro” was similar in the first three groups of animals and decreased only in old rats. iii) “In vivo” experiments showed a similar transport of 3MG in all groups of animals but a reduced transport of Gl only in aged animals. The volume of the enterocytes of old rats was consistently lower both in “in vitro” and “in vivo” experiments. Valinomycin studies indicated that the electrical properties of BBMV affected sugar uptake differently in the various ages of animals. Moreover, it seemed that old rats did not present a Na+-dependent uptake since there was no overshoot and the pattern of Gl uptake was similar when Na+ or K+ were present in the incubation medium. “In vivo” experiments showed a decreased transport of Gl only in old rats. This seems to indicate that in “in vivo” conditions other factors can influence Gl transport since this sugar, unlike 3MG, showed different transport rates in the four groups of animals during “in vitro” studies.
giu-1987
transintestinal transport; D-glucose; D-glucose uptake; brush border membrane; everted sac; jejunum; BBMV; young rat; very young rat; adult rat; aged rat; valinomycin; enterocyte volume; Na-dependent uptake
Settore BIO/09 - Fisiologia
Intestinal absorption of carbohydrates / G. Esposito, M. Tosco, C. Lindi, M.N. Orsenigo, P. Marciani, G. Monticelli, A. Faelli. ((Intervento presentato al 47. convegno Falk Symposium - Aging in Liver and Gastrointestinal Tract tenutosi a Titisee nel 1987.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/263761
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