Induction of control genes in intestinal gluconeogenesis is sequential during fasting and maximal in diabetes
| Autor: | Carine Zitoun, Amandine Gautier, Isabelle Bady, Gilles Mithieux, Fabienne Rajas, Martine Croset |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Glycerol
Male medicine.medical_specialty Physiology Metabolic Clearance Rate Endocrinology Diabetes and Metabolism Glutamine Gene Expression Regulation Enzymologic Rats Sprague-Dawley Diabetes mellitus genetics Glutaminase Physiology (medical) Internal medicine Diabetes mellitus Glycerol Kinase Intestine Small medicine Diabetes Mellitus Animals Tissue Distribution Northern blot biology Gluconeogenesis Fasting medicine.disease Small intestine Rats Enzyme Activation Endocrinology medicine.anatomical_structure Glucose biology.protein Glucose-6-Phosphatase Phosphoenolpyruvate carboxykinase Glucose 6-phosphatase Phosphoenolpyruvate Carboxykinase (ATP) |
| Zdroj: | American journal of physiology. Endocrinology and metabolism. 286(3) |
| ISSN: | 0193-1849 |
| Popis: | We studied in rats the expression of genes involved in gluconeogenesis from glutamine and glycerol in the small intestine (SI) during fasting and diabetes. From Northern blot and enzymatic studies, we report that only phospho enolpyruvate carboxykinase (PEPCK) activity is induced at 24 h of fasting, whereas glucose-6-phosphatase (G-6-Pase) activity is induced only from 48 h. Both genes then plateau, whereas glutaminase and glycerokinase strikingly rebound between 48 and 72 h. The two latter genes are fully expressed in streptozotocin-diabetic rats. From arteriovenous balance and isotopic techniques, we show that the SI does not release glucose at 24 h of fasting and that SI gluconeogenesis contributes to 35% of total glucose production in 72-h-fasted rats. The new findings are that 1) the SI can quantitatively account for up to one-third of glucose production in prolonged fasting; 2) the induction of PEPCK is not sufficient by itself to trigger SI gluconeogenesis; 3) G-6-Pase likely plays a crucial role in this process; and 4) glutaminase and glycerokinase may play a key potentiating role in the latest times of fasting and in diabetes. |
| Databáze: | OpenAIRE |
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