Integrating insulin signaling and stress responses

Chronic stress has been linked to both the onset and progression of serious health conditions, including Type 2 diabetes and cancer. Type 2 diabetes, a widespread chronic illness, is closely associated with obesity and insulin resistance, both of which often worsen under stress. Studies indicate that men experiencing high levels of chronic stress face a 45% higher risk of developing diabetes compared to those with minimal stress. Stress triggers physiological responses that elevate blood...

Insulin action is mediated through a receptor tyrosine kinase, akin to the IGF-1 receptor. The number of receptors per cell varies significantly, from 40 on erythrocytes to 300,000 on adipocytes and hepatocytes. The insulin receptor consists of linked α/β subunit dimers, forming a heterotetramer glycoprotein with two extracellular α subunits and two β subunits spanning the membrane. The α subunits inhibit the inherent tyrosine kinase activity of the β subunits, but this inhibition is released...

Stress triggers a coordinated physiological response involving the sympathetic nervous system (SNS) and the hypothalamic-pituitary-adrenal (HPA) axis. This dual activation ensures that the body is prepared for both immediate and prolonged stress management. The process begins with the perception of a stressor. This initial phase activates the SNS, leading to the rapid release of adrenaline (epinephrine) from the adrenal glands.
Role of the Sympathetic Nervous System
Adrenaline triggers the...

The response to stress—be it physical or psychological, acute or chronic—involves activation of the Hypothalamic-Pituitary-Adrenal (HPA) axis. The HPA axis is part of the neuroendocrine system because it involves both neuronal and hormonal communication. Its function is to regulate homeostatic systems—metabolic, cardiovascular, and immune—providing the necessary means to respond to a stressor.

The pancreatic islets comprising only 1%-2% of the volume are highly vascularized and innervated mini-organs. They contain five endocrine cell types, including β cells that secrete insulin, which is synthesized as a single polypeptide chain, preproinsulin, processed to proinsulin, and finally to insulin and C-peptide. This process is complex and regulated, involving the Golgi complex, the endoplasmic reticulum, and the secretory granules of the β cell.
Insulin and C-peptide are co-secreted in...

Insulin is released by beta cells of the pancreas when blood glucose levels are high. It facilitates glucose absorption and utilization in insulin-dependent cells with insulin receptors on their plasma membranes. Insulin promotes glucose uptake by increasing the number of glucose transport proteins in the cell membrane, allowing glucose to enter the cell. As a result, glucose utilization and ATP production are enhanced.
In addition to accelerating glucose uptake and utilization, insulin has...