Insulin Action on Target Cell

Insulin is a hormone that regulates glucose homeostasis in the body. It is synthesized and secreted by the beta cells of the pancreas. Insulin binds to insulin receptors on the surface of target cells, which triggers a cascade of intracellular events, leading to the uptake and utilization of glucose by the cells.

Increase in Acetyl CoA Carboxylase

Acetyl CoA carboxylase (ACC) is an enzyme that plays a key role in fatty acid synthesis. Insulin activates ACC by promoting its dephosphorylation, which leads to an increase in the production of malonyl CoA. Malonyl CoA is a precursor for fatty acid synthesis, and its increased production under insulin stimulation provides the necessary building blocks for lipid synthesis.

Increase in Glucokinase

Glucokinase is an enzyme that catalyzes the conversion of glucose to glucose-6-phosphate. It is primarily expressed in the liver and pancreatic beta cells. Insulin increases the expression and activity of glucokinase, which promotes glucose uptake and utilization by the liver and beta cells.

Increase in Glucose-6-Phosphate Dehydrogenase

Glucose-6-phosphate dehydrogenase (G6PD) is an enzyme that plays a key role in the pentose phosphate pathway, which generates NADPH for biosynthetic processes. Insulin stimulates the activity of G6PD, leading to an increased production of NADPH, which is required for fatty acid synthesis, cholesterol synthesis, and antioxidant defense.

Increase in GLUT4 Transporter

GLUT4 is a glucose transporter that is primarily expressed in adipose tissue and skeletal muscle. Insulin promotes the translocation of GLUT4 from intracellular vesicles to the plasma membrane, which increases glucose uptake by the cells. This process is mediated by the insulin signaling pathway, which activates the PI3K-Akt pathway, leading to the translocation of GLUT4 to the cell surface.

In summary, insulin action on target cells causes an increase in acetyl CoA carboxylase, glucokinase, glucose-6-phosphate dehydrogenase, and GLUT4 transporter, which promotes glucose uptake, utilization, and storage by the cells.