Mechanism of Action …..
 Corticosteroids :-
Corticosteroids secreted from Cortex of Adrenal gland…
Adrenal cortex has 3 regions..
a. Outer region Zona glomerulosa…. Secretes Mineralocorticods. ( Aldosterone)
b. Middle region Zona fasciculata….. Secretes Glucocorticoids. ( Hydrocortisone)
C. Inner region Zona reticularis … Secretes Andrigens (dihydroepiandrosterone)
 Mechanism of Action …..
 Mineralocorticoids:-
Principle mineralocorticoid is Aldosterone… Action is enhancement of SODIUM reabsorption from distal convoluted tubules in kidney.
This corticosteroid also increases the in POTASSIUM and HYDROGEN ( proton) excretion.
The action of aldosterone is exerted by gene mediated increased transcription of m-RNA in renal tubule cells which directs synthesis of proteins (aldosterone induced proteins — AIPs). These proteins acts on mitochondria to generate energy (ATP) and also synthesize the beta subunit of amiloride sensitive SODIUM channel.
So, Na* K* ATPase pump located on tubular basolateral membrane responsible for generating gradients for movement if cations in these cells is the major AIP.
In addition, aldosterone rapidly induces phosphorylation and activation of amiloride sensitive sodium channel.
