Functions of Cortical Hormones

The following points highlight the functions of various types of cortical hormones. The Functions are: 1. Mineralocorticoids 2. Functions of Glucocorticoids 3. Functions of Adrenal Sex Steroids.

Cortical Hormones # Mineralocorticoids:

This hormone is mainly secreted from zona glomerulosa.

Principal functions are given below:

1. On Mineral Metabolism:

(a) Mineralocorticoids help to increase the rate of tubular reabsorption of so­dium (Na⁺) from the renal tubules.

(b) It increases the excretion of K⁺ from distal convoluted tubule and collect­ing tubule to maintain the K⁺ concen­tration.

(c) Helps in retention of NaCI.

(d) Increased secretion may cause alka­losis while decreased secretion pro­motes acidosis.

2. On Water Metabolism:

Helps in absorp­tion of water from renal tubules to main­tain the water balance.

3. On Blood Protein:

Helps in increase of haemoglobin and plasma protein.

4. On Fat:

Stimulates fatty acid synthesis.

5. On Cardiovascular System:

(a) Hyper-secretion increases the car­diac output, while hypo-secretion re­duces the cardiac output.

(b) Excess secretion increases the arte­rial blood pressure.

6. On Fluid Volume:

(a) This hormone stimulates the thirst centre and as a result person shows thirsty.

(b) Helps to increase the plasma volume.

7. On Cellular Mechanism:

Helps in diffu­sion of lipid in cellular membranes of tu­bular epithelial cells.

Cortical Hormones # Functions of Glucocorticoids:

Glucocorticoids are primarily secreted from zona fasciculata.

Glucocorticoids possess the following functions:

1. On Carbohydrate Metabolism:

(a) Promotes gluconeogenesis in liver specially from proteins to increase blood glucose level.

(b) Stimulates glycogenesis in liver and muscle.

(c) Helps in phosphorylation of glucose- 6-P.

(d) Helps in absorption of glucose from intestine and renal tubule.

2. On Protein Metabolism:

(a) It stimulates protein synthesis in liver, but reduces protein synthesis in muscle.

(b) Glucocorticoids accelerate the breakdown of protein and inhibit amino acid uptake in extra-hepatic cells.

(c) It depresses amino acids transport into muscle cells.

(d) It enhances transport of amino acids in hepatic cells.

(e) It promotes urea synthesis in liver in presence of arginase and argino suc­cinate synthetase.

3. On Fat Metabolism:

(a) Glucocorticoids increase lipolysis in adipose tissue and may raise free fatty acids in plasma.

(b) It stimulates the synthesis of triglyc­erides in the liver.

(c) Helps in metabolism of fatty acids to ketone bodies.

(d) Stimulates fat absorption from the in­testine.

(e) It stimulates the mobilization of fatty acids and glycerol from adipose tis­sue in the blood.

4. On GI System:

(a) It stimulates oxyntic cells of stomach for secretion of HCI.

(b) It stimulates secretion of trypsinogen and pepsinogen.

(c) It inhibits absorption of calcium from small intestine.

5. On Nervous System:

(a) It influences the survival neurons.

(b) Maintains the structural integrity of brain.

(c) Excess secretion leads to reduction in threshold of electrical stimulation of brain which may cause convul­sion.

6. On Ca⁺⁺ metabolism:

(a) It reduces intestinal Ca⁺⁺ absorption.

(b) It increases urinary Ca⁺⁺ excretion.

7. On Respiratory System:

It causes matu­ration of foetal lung.

8. Effects on Cardiovascular System:

(a) It stimulates cardiac output.

(b) It increases blood pressure by en­hancing the action of catecholamine’s.

(c) It reduces capillary permeability.

9. On Muscular System:

It causes loss of muscle power.

10. On Inflammatory and Immunologic Ef­fects:

(a) It inhibits inflammatory and allergic reactions.

(b) Decreases the number of circulating monocytes, eosinophil’s and lympho­cytes.

(c) Reduces the migration of leucocytes into affected tissue.

(d) Prevents histamine release from mast cells.

(e) Inhibits the synthesis of IL-1.

11. On RBCs:

It increases red blood cells count.

Cortical Hormones # Functions of Adrenal Sex Steroids:

Zona reticularis secretes adrenal sex ste­roids. 

Principal functions of sex steroids are given below:

1. Effects in Males:

(a) May influence the growth and differ­entiation of secondary sex organs and features including pubic and axillary hair.

(b) The adult individual can cause op­posite sex attraction, coarsening of the voice.

(c) Helps is growth of muscular, growth of sex glands and increases BMR.

2. Effects in Females:

(a) These hormones may be responsible for libido in women.

(b) Overproduction may cause hirsutism and virilization.

(c) Hyper-secretion may cause involu­tion of female secondary sex char­acters.

(d) May cause development of mam­mary gland, more subcutaneous fat, less body hair and feminine voice.