Nature of elevated rat intestinal carbohydrase activities after high-carbohydrate diet feeding.
Adult rats that were maintained on a low-carbohydrate intake showed rapid increase in the activities of sucrase, maltase, and lactase along the length of the small intestine when they were fed a high-starch diet. In the present study, we have identified these activity increases, and showed that they reflect proportional accumulations in enzyme-protein of sucrase-isomaltase (EC 3.2.1.10, 3.2.1.48), maltase-glucoamylase (EC 3.2.1.20), and neutral lactase (EC 3.2.1.23). It was determined that each of these enzymes exists in adult rat intestine in single immunoreactive form and accounts as a group for all sucrase, cellobiase, and most maltase and lactase activities. Dietary change from low to high carbohydrate (starch) resulted in an increase in [3H]leucine accumulation in each of the enzymes, without a change in the amount of label accumulation in total intestinal proteins. The increase in label accumulation in the brush-border carbohydrase pools was matched generally by proportional elevation in the pool concentrations of sucrase-isomaltase and lactase but not maltase. These studies suggest that the elevation of intestinal carbohydrase concentrations induced by high-carbohydrate feeding may involve selective stimulation of their synthesis.
K K
KK
Tsuboi
L K
LK
Kwong
K
K
Yamada
P
P
Sunshine
O
O
Koldovsky
D000818:Animals; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D000939:Epitopes; D005260:Female; D006026:Glycoside Hydrolases / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D007106:Immune Sera / Q000276:immunology; D007422:Intestines / Q000032:analysis / Q000201:enzymology*; D007930:Leucine / Q000378:metabolism; D008871:Microvilli / Q000378:metabolism; D009994:Osmolar Concentration; D051381:Rats; D011919:Rats, Inbred Strains; D014316:Tritium
D004040:Dietary Carbohydrates; D000939:Epitopes; D007106:Immune Sera; D014316:Tritium; D006026:Glycoside Hydrolases; C019822:carbohydrase; D007930:Leucine