Question

Which physiologic actions result from normal insulin secretion? Select all that apply.
A. Increased liver storage of glucose as glycogen

B. Increased gluconeogenesis

C. Increased cellular uptake of blood glucose

D. Increased breakdown of lipids (fats) for fuel

E. Increased production and release of epinephrine

F. Decreased storage of free fatty acids in fat cells

G. Decreased blood glucose levels

H. Decreased blood cholesterol levels

Answer 1

The correct answers are: Option A, C, G, H

Explanation:

Insulin is secreted from beta cells of islets of langerhans of pancreas and responsible for regulation of blood glucose level. Inslulin lowers the blood glucose level by acting at several metabolic pathways and processes

• Insulin lowers the blood glucose level by increasing Glycogenesis in the liver and inhibits glycogenolysis. Thus, glucose is converted to glycogen in liver. Hence, option A is correct.
• Insulin lowers the blood glucose by increasing its cellular uptake in number of tissues such as muscles, liver, adipose tissue with the help of glucose transporters (GLUT). Hence, option C is also correct.
• The main function of insulin is to lower the blood glucose level and increase in blood glucose serves as stimulus for release of insulin. As soon as insulin is released, blood glucose is decreased. Hence, option G is also correct.
• Insulin also acts on fat metabolism, it increases the synthesis of fat and promotes the transport of blood cholesterol into adipose tissue. It also inhibits the enzymes that break triglycerides and fats and thereby decreases blood cholesterol. Hence, option H is also correct.

Thus, the correct answers are A, C, G and H.

Why the other options are incorrect?

• B. Increased gluconeogenesis: Insulin actually inhibits gluconeogenesis (production of glucose from non carbohydrate sources like proteins and fats) by blocking the release of amino acids from muscles as well as inhibiting the enzyme machinery required for gluconeogenesis. Hence, option B is not the correct answer.
• D. Increased breakdown of lipids (fats) for fuel: Insulin increases the synthesis of fat, promotes transport of fatty acids into adipose tissue but does not allow breakdown of lipids. Hence, option D is not the correct answer.
• E. Increased production and release of epinephrine: Insulin is mainly responsible for lowering of blood glucose. Absence of insuliln can lead to release of counterregulatory hormones like cortisol, glucagon and epinephrine resulting in Diabetic ketoacidosis. However, insulin does not increase or promote the release of epinephrine. Hence, option E is also incorrect.
• F. Decreased storage of free fatty acids in fat cells: Insulin increases the storage of free fatty acids into adipose tissue but does not decrease their storage. Hence, option F is also incorrect.