Insulin release, peripheral insulin resistance and muscle function in protein malnutrition: a role of tricarboxylic acid cycle anaplerosis.
نویسندگان
چکیده
Pancreatic beta-cells and skeletal muscle act in a synergic way in the control of systemic glucose homeostasis. Several pyruvate-dependent and -independent shuttles enhance tricarboxylic acid cycle intermediate (TACI) anaplerosis and increase beta-cell ATP:ADP ratio, triggering insulin exocytotic mechanisms. In addition, mitochondrial TACI cataplerosis gives rise to the so-called metabolic coupling factors, which are also related to insulin release. Peripheral insulin resistance seems to be related to skeletal muscle fatty acid (FA) accumulation and oxidation imbalance. In this sense, exercise has been shown to enhance skeletal muscle TACI anaplerosis, increasing FA oxidation and by this manner restores insulin sensitivity. Protein malnutrition reduces beta-cell insulin synthesis, release and peripheral sensitivity. Despite little available data concerning mitochondrial metabolism under protein malnutrition, evidence points towards reduced beta-cell and skeletal muscle mitochondrial capacity. The observed decrease in insulin synthesis and release may reflect reduced anaplerotic and cataplerotic capacity. Furthermore, insulin release is tightly coupled to ATP:ADP rise which in turn is related to TACI anaplerosis. The effect of protein malnutrition upon peripheral insulin resistance is time-dependent and directly related to FA oxidation capacity. In contrast to beta-cells, TACI anaplerosis and cataplerosis pathways in skeletal muscle seem to control FA oxidation and regulate insulin resistance.
منابع مشابه
Conjugated linoleic acid supplementation enhances insulin sensitivity and peroxisome proliferator-activated receptor gamma and glucose transporter type 4 protein expression in the skeletal muscles of rats during endurance exercise
Objective(s):This study examined whether conjugated linoleic acid (CLA) supplementation affects insulin sensitivity and peroxisome proliferator-activated receptor gamma (PPAR-γ) and glucose transporter type 4 (GLUT-4) protein expressions in the skeletal muscles of rats during endurance exercise. Materials and Methods:Sprague-Dawley male rats were randomly divided into HS (high-fat diet (HFD) s...
متن کاملThe Role of Fetuin-A in Diabetes and Obesity: The Mechanism and Action
Fetuin-A is a phosphorylated glycoprotein produced by liver.It by binding to calcium ion inhibits ectopic calcium deposition and protects vascular calcification. Fetuin-A acts as a multifactorial protein and its role has been documented from brain development to bone remodeling and immune function, regulation of insulin activity, hepatocyte growth factor activity and inhibition lymphocyte blast...
متن کاملAnaplerotic input is sufficient to induce time-dependent potentiation of insulin release in rat pancreatic islets.
Nutrients that induce biphasic insulin release, such as glucose and leucine, provide acetyl-CoA and anaplerotic input in the beta-cell. The first phase of release requires increased ATP production leading to increased intracellular Ca(2+) concentration ([Ca(2+)](i)). The second phase requires increased [Ca(2+)](i) and anaplerosis. There is strong evidence to indicate that the second phase is du...
متن کاملSIRT3 Is Crucial for Maintaining Skeletal Muscle Insulin Action and Protects Against Severe Insulin Resistance in High-Fat–Fed Mice
Protein hyperacetylation is associated with glucose intolerance and insulin resistance, suggesting that the enzymes regulating the acetylome play a role in this pathological process. Sirtuin 3 (SIRT3), the primary mitochondrial deacetylase, has been linked to energy homeostasis. Thus, it is hypothesized that the dysregulation of the mitochondrial acetylation state, via genetic deletion of SIRT3...
متن کاملEffect of Eight Weeks of High Intensity Interval Training on Insulin Resistance and IRS1 Gene Expression in Gastrocnemius Muscle of Obese Wistar Rats
Background and objectives: The role of genetic components in expression of proteins involved in signaling pathways of fat and carbohydrate metabolism has been well-demonstrated. The aim of this study was to determine effects of high intensity interval training (HIIT) on glucose, insulin, and insulin resistance levels as well as IRS1 expression in gastrocnemius muscle of obese Wistar rats. Meth...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- The British journal of nutrition
دوره 103 9 شماره
صفحات -
تاریخ انتشار 2010