Intestinal mucosa in diabetic rats: studies of microvillus membrane composition and microviscosity.
In experimental diabetes, a number of intestinal brush-border hydrolases and transport systems are stimulated. In this study, we assessed possible effects of diabetes on the composition and membrane fluidity of rat intestinal brush-border membranes that might correlate with these functional changes. We found similar proportions of lipid and protein in the diabetic and control preparations, although there was a considerable increase in total membrane from the diabetic rats, presumably reflecting mucosal hyperplasia. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of membrane protein revealed an increase in the bands corresponding to sucrase-isomaltase, consistent with an increased enzyme activity of sucrase. Membrane lipid analysis revealed only a decrease in fatty acids of the neutral lipid fraction of diabetics--a change that may well have occurred during membrane preparation. 1-6-Diphenyl-1,3,5-hexatriene fluorescence polarization data, obtained as a function of temperature, was similar for the diabetic and control rats, with a three-phase linear model superior to one- and two-phase linear or quadratic models. The overall composition of the intestinal brush-border membrane, unlike other plasma membranes, appears little affected by experimental diabetes.
D000818:Animals; D002241:Carbohydrates / Q000302:isolation & purification; D002855:Chromatography, Thin Layer; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005454:Fluorescence Polarization; D007413:Intestinal Mucosa / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D008560:Membrane Fluidity; D008563:Membrane Lipids / Q000302:isolation & purification; D008565:Membrane Proteins / Q000302:isolation & purification; D008871:Microvilli / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D002241:Carbohydrates; D008563:Membrane Lipids; D008565:Membrane Proteins