Hormones of Adrenal Cortex
1. Mineralocorticoides
(by zona glomerulosa only)
2. Glucocorticoids
3. Gonadocorticoids/ sex hormone
1. Mineralocorticoides (Aldosterone)
Aldosterone is main mineralocorticoids. Its functions are associated with maintenance of water and electrolyte balance in body.
Function of Mineralocorticoides
Aldosterone regulates homeostasis of two minerals ions Na +and K+ maintaining sodium ion balance is aldosterone's primary job.
Through negative feedback system it stimulates reabsorption of sodium (Na+ ) by renal tubules and excretion of potassium (K+) in urine
Aldosterone reduces excretion of Na+ from body.
Sodium reabsorption is also accompanied by retention of water and therefore aldosterone is involved in regulation of blood volume and blood pressure too.
Aldosterone also enhances Na+ reabsorption from perspiration, saliva.
The blood potassium level regulates amount of aldosterone produced by adrenal cortex .
Regulation of secretion
When blood potassium levels rise,, more aldosterone is secreted. Low blood potassium has opposite effect.
Angiotensin also stimulate release of aldosterone.
Low renal blood
Low Blood volume
Low Blood pressure
Low Blood sodium
Kidney
Secretion bof Renin
Angiotensinogen -- Angiotensin l
Angiotensin ll. Vasoconstriction
Adrenal Cortex
Secretion of aldosterone
Kidney tubules
Increase reabsorption of sodium and water
Increase excretion of potassium
Increase blood sodium levels
Increase blood volume
Increase blood pressure
Renin angiotensin mechanism
When renal blood flow is reduced or blood sodium levels fall, the enzyme renin is secreted by kidney cells.
Renin converts plasma protein Angiotensinogen produced by liver, to angiotensin l.
Angiotensin converting enzyme (ACE), formed in small quantities in lungs, proximal kidney tubules and other tissues.
Convert Angiotensin l to Angiotensin ll, which stimulates secretion of aldosterone.
It also causes vasoconstriction and increases blood pressure.
Aldosterone secretion is stimulated by low blood levels of Na+.
Increased K+ stimulates, whereas decreased K+ inhibits aldosterone release.
2. Gonadocorticoids / Sex hormones
Gonadocorticoids secreted by adrenal cortex; male sex hormone, androgen in male and female sex hormone; estrogen in female.
3. Glucocorticoids
Glucocorticoids influence energy metabolism of most body cells and help us to resist stressors and anti-inflammatory response glucocorticoid hormones include cortisol hormone.
Function of Glucocorticoids
1. Best know is their role in stress relief, often called Stress hormone.
2. This hormone helps produce wake-up signal, turning on appetite and physical activity.
3. Glucocorticoids stimulates fat and protein catabolism, Gluconeogenesis and release of fatty acids and glucose into blood.
4. Cortisol enhances epinephrine's vasoconstriction effect and rise blood pressure and circulatory efficiency that help to nutrients quickly distributed to cell's.
5. Excessive level of Glucocorticoids; depress cartilage and bone formation.
By decreasing releasing of inflammation chemicals and preventing vasodilation.
Use of Glucocorticoid drugs to control symptoms of many chronic inflammatory disorder. Such as Rheumatoid arthritis and allergic response.
Regulation of Secretion
Glucocorticoid secretion is regulated by negative feedback.
Hypothalamus
Corticotropin releasing hormone (CRH)
Anterior lobe of pituitary gland
Adrenocorticotropic hormone (ACTH)
Adrenal Cortex
Raised blood Glucocorticoid levels
Use by body cell
Lowered blood Glucocorticoid levels
(Negative feedback regulation of Glucocorticoid secretion)
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