Insulin and Glutathione Quiz

Glutathione Insulin Transhydrogenase (Insulinase)

• Insulinase plays a role in regulating insulin and glucose profiles in non-diabetic individuals across meal times.
• Insulin levels peak post-meal to facilitate glucose uptake and prevent excessive blood sugar elevation.

Normal Insulin Metabolism

• Post-meal insulin action includes:
  • Storing glucose as glycogen.
  • Inhibiting gluconeogenesis.
  • Enhancing fat storage in adipose tissue.
  • Increasing protein synthesis.

Biological Effects of Insulin

• Promotes cell growth and development, mediated by factors like epidermal growth factor and prostaglandins.

Regulation of Insulin Secretion

• Insulin secretion is stimulated by rising blood glucose levels after meals.

Effects of Insulin on Carbohydrate Metabolism

• Enhances glucose uptake in:
  • Skeletal and cardiac muscles.
  • Adipose tissue.
  • Mammary glands.
• Tissues that are independent of insulin for glucose uptake:
  • Brain, red blood cells (RBC), testis, kidneys, retina, intestinal mucosal cells.

Carbohydrate Metabolism Enzyme Activity

• Glycolysis: Increased activity of glucokinase, phosphofructokinase, and pyruvate kinase.
• Glycogenesis: Increased glycogen synthase.
• HMP shunt: Increased glucose 6-phosphate dehydrogenase.
• Gluconeogenesis: Decreased activity of key gluconeogenesis enzymes.
• Glycogenolysis: Decreased glycogen phosphorylase activity.

Lipid Metabolism

• Lipogenesis is increased, promoting:
  • De novo fatty acid synthesis via acetyl CoA carboxylase.
  • Availability of NADPH.
• Adipose tissue support for lipoprotein lipase activity increases.
• Lipolysis is decreased, affecting hormone-sensitive lipase.
• Ketogenesis is inhibited.

Protein Metabolism

• Protein synthesis is enhanced through:
  • Increased RNA polymerase activity and amino acid uptake.
• Protein degradation is inhibited by decreased transaminases and deaminases.

Adverse Effects of Insulin

• Potential negative effects include:
  • Hypoglycemia, lipoatrophy, lipohypertrophy, obesity.
  • Insulin allergy and formation of insulin antibodies.
  • Insulin-induced edema.

Diabetes Symptoms and Classification

• Primary symptoms of diabetes include frequent urination, excessive thirst, hunger, weight loss, fatigue, and vision impairment.
• Diabetes mellitus is characterized by chronic hyperglycemia due to defects in insulin production or action.

Type 2 Diabetes Mellitus

• Typically affects individuals over 40 and is associated with obesity in 80-90% of cases.
• Insulin resistance is a key feature, leading to inadequate glucose utilization and persistent hyperglycemia.
• Precursor conditions include impaired glucose tolerance (IGT) and impaired fasting glucose (IFG).

Prediabetes

• A condition where blood glucose levels are elevated but not high enough for a diabetes diagnosis.
• Weight loss and increased physical activity can delay or prevent progression to diabetes.

Gestational Diabetes

• Diagnosed in some women during pregnancy, particularly those who are obese or have a family history of diabetes.
• Requires treatment during pregnancy to avoid complications in the infant.

Other Forms of Diabetes

• Includes types resulting from specific genetic conditions, surgery, drugs, or infections.
• Maturity-Onset Diabetes of the Young (MODY) arises from genetic mutations affecting insulin release and can arise at any age.
• Latent Autoimmune Diabetes in Adults (LADA) mimics type 2 diabetes initially but progresses quickly to insulin dependence in many cases.

Insulin and Hypoglycemia

• Hypoglycemia occurs when blood glucose levels drop below normal, leading to various nervous system symptoms.
• Symptoms of hypoglycemia can be relieved by administering glucose.
• Compensatory mechanisms include hormone secretion that opposes insulin to restore blood sugar levels.

Insulin Preparation

• Available in short-acting and long-acting formulations to manage blood glucose levels effectively.