Insulin is an anabolic hormone that acts on various target tissues, including the liver, skeletal muscle, and fat tissue, regulating the blood glucose level [1,2,3,4].
Which cells need insulin for glucose uptake?
Insulin facilitates entry of glucose into muscle, adipose and several other tissues. The only mechanism by which cells can take up glucose is by facilitated diffusion through a family of hexose transporters.
What cells are insulin dependent?
Those tissues defined as insulin dependent, based on intracellular glucose transport, are principally adipose tissue and muscle.
How does insulin help glucose uptake by cells?
Insulin increases glucose uptake mainly by enriching the concentration of Glut4 proteins at the plasma membrane, rather than by increasing the intrinsic activity of the transporter (2,3).
Do brain cells need insulin for glucose uptake?
As insulin is not required for GLUT1- or GLUT3-mediated glucose transport, insulin is not needed for glucose transport into most brain cells. Insulin does, however, play a role as a neuroregulatory peptide, and this role is slowly being unraveled (5).
What causes cells to become insulin resistant?
What Causes Insulin Resistance? It isn’t clear exactly what causes insulin resistance, but a family history of type 2 diabetes, being overweight (especially around the waist), and being inactive all can raise the risk. You do not have to be overweight to have insulin resistance.
What causes glucose uptake?
In skeletal muscle and adipose tissue, insulin promotes membrane trafficking of the glucose transporter GLUT4 from GLUT4 storage vesicles to the plasma membrane, thereby facilitating the uptake of glucose from the circulation.
What are glucose dependent tissues?
Glucose homeostasis is primarily dependent on the balance between glucose production by the liver and glucose consumption by insulin dependent tissues (such as muscle, adipose tissue) and noninsulin dependent tissues (such as brain).
What is insulin independent glucose uptake?
The glucose transport proteins (GLUT1 and GLUT4) facilitate glucose transport into insulin-sensitive cells. GLUT1 is insulin-independent and is widely distributed in different tissues. … Thus, insulin-independent glucose transport through GLUT1 can meet the basal needs of the muscle cell.
How does lack of insulin prevent the cell from using glucose?
Without insulin, cells are unable to use glucose as fuel and they will start malfunctioning. Extra glucose that is not used by the cells will be converted and stored as fat so it can be used to provide energy when glucose levels are too low.
How does insulin interact with cells?
Cells obtain energy from glucose or convert it to fat for long-term storage. Like a key fits into a lock, insulin binds to receptors on the cell’s surface, causing GLUT4 molecules to come to the cell’s surface. As their name implies, glucose transporter proteins act as vehicles to ferry glucose inside the cell.
How is insulin transported through the cell membrane?
The insulin circulates through the blood stream until it binds to an insulin receptor embedded in the cell membrane of a muscle, fat, or brain cell. Once the insulin binds to the receptor, phosphate groups are added to the intracellular domain of the receptor.
Does insulin increase glucose uptake in brain?
We conclude that basal insulin has a role in regulating global brain glucose uptake in humans, mostly marked in cortical areas. The effect of insulin in peripheral tissues is the stimulation of glucose uptake, oxidation, and storage.
Does insulin affect glucose in brain?
In summary, insulin is a key hormone that regulates blood glucose and fat levels that has several neuroprotective and homeostatic roles within the brain, ranging from cognition, feeding behavior, peripheral energy metabolism, and emotion.
What does the brain depend on for its glucose supply?
The mammalian brain depends on glucose as its main source of energy. … Glucose metabolism provides the fuel for physiological brain function through the generation of ATP, the foundation for neuronal and non-neuronal cellular maintenance, as well as the generation of neurotransmitters.