Question

why is the amount of glucose in the body so critical to metabolim and homeostasis

how does hyperinsulinism influence blood glucose

Answer 1

a. Glucose is the main source of energy to the body. It supplies ATP for catabolic reactions to occur. It is required for transition from neonatal to adult life. Although other organs and cells can use fats and other sources of energy, brain and red blood cells use only glucose. Low levels of glucose will severely inhibit brain functioning. Neurons require constant supply of energy from glucose for synaptic transmission. Glucose metabolizing enzymes provide ATP from glucose for apoptotic cell death pathways. However, if glucose levels rise in body, then this glucose can be converted to saturated fat by insulin.

Metabolism of glucose requires insulin function as glucose cannot enter the cells directly. It requires glucose transporters to enter the cells. Insulin will increase expression of glucose transporters in the cell. Glucagon, on the other hand, will oppose insulin actions and will increase glucose levels in blood. Hormones, insulin and glucagon are required for maintaining glucose levels for homeostasis and are produced by islets of Langerhans in pancreas. Homeostasis maintains constant stable internal environment in the body. Insulin also stimulates glycogenesis in liver while glucagon stimulates gluconeogenesis. When glucose levels rise in blood, insulin is released to lower blood glucose. Low levels of glucose stimulate secretion of glucagon to increase blood sugar levels. If glucose levels are not maintained in this fashion, diabetes will result. Inability to utilize glucose has serious consequences to maintain metabolism and homeostasis. Glucose is required by RBCs for transporting oxygen. Thus, aberrant glucose levels will affect circulation. There are severe effects on the brain due to decreased glucose availability. Glucose imbalances lead to hypertension, lipids imbalances and obesity. There are severe effects on eyes, kidneys and liver. One complication of diabetes is ketoacidosis, wherein ketone bodies are formed from fats. This leads to increase hydrogen ion concentration in body, causing acidosis. Ketoacidosis can result in coma and death. Effects of increased blood glucose on kidneys can result in regulation of water balance. Diabetes also affects the neuroendocrine system. Thus, maintaining glucose levels in body is very crucial for metabolism and homeostasis.

b. Hyperinsulinemia is the increased production of insulin in the body. Insulin binds to its receptors on target cells in the body and increases transcription of glucose transporter via the PI3K-AKT pathway. Glucose transporters SGLUTs and GLUTs are required for transporting glucose across the cell membrane for glycolysis. Hyperinsulinemia is mostly an effect of insulin resistance. The pancreas will secrete more insulin to compensate for insulin resistance. Hyperinsulinemia is known to result in type 2 diabetes, where the levels of glucose in blood increases. Despite increased synthesis of insulin, cells are unable to utilize this insulin for glucose transport. This will result in increased levels of glucose in blood while cells will have poor ATP levels due to decreased glycolysis. As a result, cells will utilize stored fats for ATP.