Regulation of glucose-6-phosphate dehydrogenase synthesis and mRNA abundance in cultured rat hepatocytes
| Autor: | P Manos, Roderick Nakayama, D Holten |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
congenital
hereditary and neonatal diseases and abnormalities medicine.medical_specialty medicine.medical_treatment Fructose Glucosephosphate Dehydrogenase Biology Biochemistry Dexamethasone Gene Expression Regulation Enzymologic chemistry.chemical_compound hemic and lymphatic diseases Internal medicine parasitic diseases medicine Animals Insulin Glucose-6-phosphate dehydrogenase RNA Messenger Molecular Biology Cells Cultured chemistry.chemical_classification nutritional and metabolic diseases Rats Inbred Strains Cell Biology Carbohydrate Rats Amino acid Kinetics Endocrinology medicine.anatomical_structure Liver chemistry Enzyme Induction Hepatocyte Triiodothyronine Energy source Research Article Hormone |
| Zdroj: | Biochemical Journal. 276:245-250 |
| ISSN: | 1470-8728 0264-6021 |
| DOI: | 10.1042/bj2760245 |
| Popis: | Conditions were identified which, for the first time, demonstrate that primary hepatocytes can express the same range of glucose-6-phosphate dehydrogenase (G6PD) synthesis and mRNA as in live rats. Primary hepatocytes were cultured without prior exposure to serum, hormones or carbohydrates. Five modulators implicated in G6PD induction in vivo were examined: insulin, dexamethasone, tri-iodothyronine (T3), glucose and fructose, T3 did not affect G6PD activity, and did not interact with carbohydrate to affect the activity of G6PD. Neither glucose nor fructose alone affected G6PD activity, and they did not interact with insulin to increase G6PD activity. Hepatocytes isolated from fasted rats and cultured in serum-free media with amino acids ad the only energy source how a 12-fold increase in G6PD synthesis and mRNA (measured by a solution-hybridization assay). This induction does not require added hormones or carbohydrate. The addition of insulin alone caused another increase in G6PD synthesis and mRNA. There are at least three distinct phases to G6PD induction under these conditions. The largest increase in G6PD synthesis (12-fold) occurs in the absence of any hormones and with amino acids as the only energy source. This phase is due to increased G6PD mRNA. Insulin causes an additional 2-3-fold increase in G6PD synthesis and mRNA. However, dexamethasone and insulin are both required before G6PD synthesis is equal to that in rats which are fasted and refed on a high-carbohydrate diet. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|