Insulin and IGE-1 receptors in a human intestinal adenocarcinoma cell line (CACO-2): regulation of Na+ glucose transport across the brush border.
Both insulin and IGF-1 receptors are present in intestinal mucosal cells, although their role in this tissue is unclear. We have characterized these receptors in a human adenocarcinoma cell line, Caco-2, and examined their role in the regulation of glucose transport and absorption in these cells. The Caco-2 cells demonstrated specific insulin and IGF-1 receptors. They also bound cytochalasin B, suggesting the presence of a glucose transporter-like protein. When grown on membranes, the Caco-2 cells formed columnar, bipolar cells with tight junctions. The monolayer selectively transported D-glucose and methyl-D-glucose, with complete exclusion of L-glucose, D-mannitol and inulin. The absorption of glucose across the monolayer occurred via a Na+/glucose cotransporter, as indicated by a change in short circuit current after addition of glucose to the apical membrane. When examined under several conditions, neither insulin nor IGF-1 had an affect on the transport of glucose across the Caco-2 monolayer, nor the production of lactate by the cells. It is concluded that the insulin and IGF-1 receptors of Caco-2 cells do not regulate glucose transport.
MacDonald
R S
RS
Department of Food Science and Human Nutrition, University of Missouri, Columbia 65211.
Thornton
W H
WH
Bean
T L
TL
D000230:Adenocarcinoma / Q000378:metabolism*; D001692:Biological Transport; D003110:Colonic Neoplasms / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D008871:Microvilli / Q000378:metabolism; D017526:Receptor, IGF Type 1 / Q000032:analysis / Q000502:physiology*; D011972:Receptor, Insulin / Q000032:analysis / Q000502:physiology*; D012964:Sodium / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D012964:Sodium; D017526:Receptor, IGF Type 1; D011972:Receptor, Insulin; D005947:Glucose