In this article we will discuss about the role of different organs in carbohydrate metabolism. After reading this article you will learn about: 1. Role of Pancreas 2. Role of Adrenal Cortex 3. Role of Adrenal Medulla 4. Role of Thyroid Gland 5. Role of Adenohypophysis.
1. Role of Pancreas in Carbohydrate Metabolism:
Pancreas plays essential role in carbohydrate metabolism α and β cells of endocrine pancreas secrete glucagon and insulin respectively which are antagonistic in actions. In well fed stage sugar molecules stimulate β-cells for secretion of insulin; in-turn insulin lowers the blood glucose level through glycogenesis.
In fasting condition, lower blood glucose level stimulates α-cells for secretion of glucagon hormone which increases the blood sugar level by glycogenolysis and gluconeogenesis.
2. Role of Adrenal Cortex in Carbohydrate Metabolism:
Hormone glucocorticoid (Cortisol) involves in carbohydrate metabolism very effectively.
Different roles are given below:
1. Decreased glucose utilization:
The blood glucose concentration is raised due to increased rate of gluconeogenesis. The enzyme glucose-6-phosphatase catalyses this reaction in liver and thus blood glucose level is increased.
2. Protein breakdown:
It enhances protein breakdown to the formation of free amino acids which in turn is involved in gluconeogenesis.
3. Anti-insulin effect:
It shows anti-insulin effect to the peripheral tissue by inhibiting uptake of glucose.
3. Role of Adrenal Medulla in Carbohydrate Metabolism:
Hormone epinephrine and norepinephrine are involved in carbohydrate metabolism in following ways:
1. Raise blood sugar level by promoting glycogenolysis in liver.
2. Promotes gluconeogenesis from blood lactic acid in muscles.
3. Epinephrine inhibits insulin secretion but on other hand stimulates glucagon secretion.
4. Epinephrine acts as inducer for synthesis of gluconeogenic enzymes like pyruvate carboxylase, FD Pase, G-6-phosphatase.
4. Role of Thyroid Gland in Carbohydrate Metabolism:
T3 and T4 hormones involve in carbohydrate metabolism by following ways:
1. Thyroid hormone enhances intestinal absorption of glucose.
2. Enhances gluconeogenesis in liver.
3. Stimulates glycogenolysis in liver.
4. May cause the breakdown of insulin.
5. Role of Adenohypophysis in Carbohydrate Metabolism:
The growth hormone STH is also involved in carbohydrate metabolism. Its actions are as follows:
1. Elevates blood glucose level by enhancing the release of glucose from liver glycogen i.e., glycogenolysis.
2. It reduces glucose uptake in muscle.
3. It increases the number of α-cells in islets of pancreas.