Question

Which of the following statement is correct?

• A. Glucagon and insulin are secreted by different cells and have opposite effect.
• B. Glucagon and insulin are secreted by different organs.
• C. None of the above
• D. Glucagon and insulin are secreted by same cells.

Answer 1

The correct option is A Glucagon and insulin are secreted by different cells and have opposite effect.

The two main types Islet of Langerhans in the pancreatic cells are $\alpha$-cells and $\beta$-cells. The $\alpha$-cells secrete a hormone called glucagon, while the $\beta$-cells secrete insulin. Both glucagon and insulin are peptide hormone.

Glucagon play an important role in maintaining the normal blood glucose levels. Glucagon acts mainly on the liver cells (hepatocytes) and stimulates glycogenolysis resulting in an increased blood sugar (hyperglycaemia), so called as hyperglycaemic factor.

Insulin plays a major role in the regulation of glucose homeostasis. Insulin acts mainly on hepatocytes and adipocytes (cells of adipose tissue) and enhances cellular glucose uptake and utilisation. This results in decreased blood glucose levels (hypoglycaemia), so it is also referred to as hypoglycaemic factor.

So, insulin and glucagon are secreted by different cells (Islet of Langerhans) and have opposite effect on the body.