Intestinal adaptation to diabetes. Altered Na-dependent nutrient absorption in streptozocin-treated chronically diabetic rats.
To examine the pattern and mechanisms of enhanced intestinal nutrient absorption in diabetes, we measured intestinal transport of 3-O-methylglucose (3OMG), l-alanine (ALA), and SO4 in male Lewis rats made diabetic with streptozocin. Diabetes enhanced 3OMG absorption fivefold in ileum and threefold in jejunum; ALA absorption increased twofold in ileum but not at all in jejunum; ileal SO4 transport was unaffected. Increases in 3OMG and ALA transport were due solely to increases in maximum velocity. The enhancement of ileal glucose absorption was half-maximal in 40-45 d, could be reversed by 10 d of treatment with insulin and did not result from adrenergic denervation. The density of glucose carriers per milligram brush border protein (measured as [3H]phlorizin binding sites) was not altered but there was a sixfold increase in the number of glucose-inhibitable [3H]phlorizin-binding sites in the intact epithelium. Generalized mucosal hypertrophy accounted for less than 30% of this increase. We conclude that the intestine adapts to streptozocin-induced diabetes through recruitment of additional brush border carriers for sugar, probably in the midvillus-to-crypt region.
D019325:3-O-Methylglucose; D000409:Alanine / Q000378:metabolism; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D006892:Hydroxydopamines / Q000494:pharmacology; D007082:Ileum / Q000294:innervation / Q000378:metabolism; D007408:Intestinal Absorption / Q000187:drug effects*; D007583:Jejunum / Q000294:innervation / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008757:Methylglucosides / Q000378:metabolism; D008871:Microvilli / Q000187:drug effects / Q000378:metabolism; D016627:Oxidopamine; D010695:Phlorhizin / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D011917:Rats, Inbred Lew; D012964:Sodium / Q000494:pharmacology*; D013311:Streptozocin; D013431:Sulfates / Q000378:metabolism; D013563:Sympathectomy, Chemical
D002352:Carrier Proteins; D006892:Hydroxydopamines; D008757:Methylglucosides; D013431:Sulfates; C035685:phlorizin-binding protein, mammal; D019325:3-O-Methylglucose; D013311:Streptozocin; D016627:Oxidopamine; D012964:Sodium; D010695:Phlorhizin; D000409:Alanine