Mineralocorticoids Synthesis Process lec3 endocrine

Mineralocorticoids Synthesis

• Mineralocorticoids synthesis occurs in the zona glomerulosa.
• The most potent mineralocorticoid produced is aldosterone.
• The synthesis of aldosterone involves four steps:

Step 1: Conversion of Pregnenolone to Progesterone

• Pregnenolone in the smooth endoplasmic reticulum is converted into progesterone.
• This conversion occurs due to the absence of 17α-hydroxylase enzyme in zona glomerulosa.
• The conversion is facilitated by two enzymes: 3β-hydroxysteroid dehydrogenase (3β-OHSD) and 5'4 isomerase.

Step 2: Hydroxylation of Progesterone

• Progesterone is hydroxylated at the C21 position by the 21-hydroxylase enzyme.
• This forms 11-deoxycorticosterone (DOC).

Step 3: Formation of Corticosterone

• DOC leaves the smooth endoplasmic reticulum and enters the mitochondria.
• In the mitochondria, DOC is subjected to hydroxylation at the C11 position by the 11β hydroxylase enzyme.
• This forms corticosterone.

Step 4: Formation of Aldosterone

• In the zona glomerulosa, corticosterone is hydroxylated at the C18 position by the 18-hydroxylase (aldosterone synthase) enzyme.
• This forms aldosterone.