Question

Insulin is not produced in patients with Type I diabetes. (A) Explain how insulin decreases blood glucose levels. (B) Describe three different abnormalities in a liver cell that could lead to the high concentration of glucose in the blood that is observed in patients with Type I diabetes. Explain why each will lead to high blood glucose level. (C) Insulin is produced in patients with Type II diabetes but the cells do not respond to it. Based on your answer to part (A and B), hypothesize a potential target for a drug that could be developed to treat Type II diabetes since insulin injections are not very successful. (8 pt)

Answer 1

Insulin: Insulin is a peptide produced by beta cells of pancrease which reglates the metabolism of fats, carbohydrates and protiens by absorption of glucose from blood to liver, skeletal muscles.

A. Insulin causes the liver to convert glucose into glycogen - theprocess called as glycogenesis, where 2/3 of the body cells (primary muscles and fat tissue cells) are forced to take up the glucose from blood through GLUT4 (Glucose Transporter Type 4) transporter which in turn leads to the decrease in the blood glucose level.

B. Abnormalities in liver cell:

1. Glycogen Deposition: In 80% of diabetic people excess glycogen is stored in the liver cells. Glycogen synthesis is impaired due to the defective activation of glycogen synthase.

2. Fatty liver: Fat is stored in the liver in the form of triglycerides which manifests increased transport of fat to liver, enhances hepatic fat synthesis and decreases the removal of fat from liver.

3. Liver Cirrhosis: The study shows that 80% of diabetic people with cirrhosis have glucose intollerance and cirrhosis in diabetics vary widely.

C. Obesity is a major risk factor in most of the diabetic people but in ectreme obesity cases, insulin sensitivity is found to be normal. Due to inadequate production of insulin secreated nor the insulin injection are not found to be potential to treat type II diabetics, which can be controlled by controlled diet theraphy method and hypoglycemic agents (drugs used in diabetics by altering glucose levels in the blood). These agents helps to increase the amount of insulin secreated ny pancrease, increases the sensitivity of the targeted organs to insulin and decreases the rate of absorption of glucose from gastrointestinial tract.