Question

What are the effects of the following hormones? Where are they secreted? What are their targets and effects?

1. Adrenocorticotropin hormone

2. Aldosterone

3. Calcitonin

4. Cortisol

5. Growth Hormone

6. Prolactin

7. Glucagon & Insulin

8. parathyroid hormone

9. Luteinizing hormone

10. Melanocyte stimulating hormone

Answer 1

1. Adrenocorticotropin hormone (ACTH) :

It is secreted from anterior pituitary via hypothalamus hypophysial portal system.

The target of ACTH is adrenal cortex.

ACTH helps in synthesis of glucocorticoids, mineralocorticoids, sex steroids from the precursor cholesterol.

2. Aldosterone :

It is secreted from zona glomerulosa of adrenal cortex.

The target organ of aldosterone is kidney.

The main function is to maintain the electrolyte and water balance by increasing the Na+ and water reabsorption.

3. Calcitonin :

Secreted from parafollicular cells of thyroid gland.

The target locations are bone and kidney.

In bone it decreases the osteoclastic activity thereby inhibit bone resorption whereas in kidney it decreases calcium reabsorption and causes calciuria thus the plasma calcium level and plasma phosphate level decreases.

4. Cortisol :

It is secreted from zona fasiculata of adrenal cortex.

The target organs are mostly tissues like liver, muscle, adipose and many other organs.

The major effect is that, it increases the blood glucose level and it also has anti-inflammatory, immunosupressive actions and permissive actions that allows specific actions of other hormones.

5. Growth Hormone (GH) :

Secreted by anterior pituitary gland (acidophil cells)

Bone, cartilage, connective tissue, liver and others like thymus are the target organs.

GH promotes skeletal growth, increases protein synthesis, increases glucose levels, decreases lipids by lipolysis.

6. Prolactin:

Secreted by anterior pituitary gland (acidophil cells).

Mammary glands in the breast are the target organs.

Prolactin plays important role in development of mammary glands and in milk synthesis.

7. Glucagon and Insulin:

Glucagon secreted by alpha cells of islets of langerhans in pancreas whereas insulin secreted by beta cells of islets of langerhans in pancreas.

Liver is the main target organ.

Both involved in regulation of glucose levels in blood.

Glucagon increases the sugar levels where Insulin decreases the levels of glucose in blood.

8. Parathyroid hormone:

Secreted from chief cells of parathyroid gland.

Bone, Kidney and GIT are the main targets of this hormone.

The hormone increases the levels of calcium and phosphate in blood.

9. Luetinizing hormone (LH):

Secreted by gonadotrophic cells of anterior pituitary gland.

Testes in males and ovaries in females are the target organs.

It increases the testosterone secretion in males, maturation of ovarian follicles, ovulation, corpus luteum formation in females.

10. Melanocyte stimulating hormone (MSH):

Secreted from intermediate lobe of pituitary gland.

Skin is the target organ.

It increases the synthesis of melanin which causes darkening of the skin.