Adrenal steroid hormone synthetic pathway. Cholesterol is converted to pregnenolone by the cytochrome P450 side-chain cleavage enzyme.
Pregnenolone is converted to progesterone by 3β-hydroxysteroid dehydrogenase or to 17α-OH-pregnenolone by 17α-hydroxylase. Thereafter, 17α-OHpregnenolone is converted to 17α-OH-progesterone by 3β-hydroxysteroid dehydrogenase, 17α-OH-progesterone is converted to 11-deoxycortisol by the
enzyme 21-hydroxylase, and 11-deoxycortisol is converted to cortisol by 11β-hydroxylase. In addition, 17α-OH-progesterone can be converted to
androstenedione. Both 17α-OH-pregnenolone and 17α-OH-progesterone can be converted to the androgens dehydroepiandrosterone (DHEA) and
androstenedione, respectively. DHEA is converted to androstenedione. Cells in the zona glomerulosa do not have 17α-hydroxylase activity. Therefore,
Source: Chapter 6. Adrenal Gland, Endocrine Physiology, 4e
pregnenolone can be converted only into progesterone. The zona glomerulosa possesses aldosterone synthase activity, and this enzyme converts
Citation: Molina
PE. Endocrinecorticosterone
Physiology, 4e;to2013
Available at: http://mhmedical.com/
Accessed: July 31, 2017
deoxycorticosterone
to corticosterone,
18-hydroxycorticosterone,
and 18-hydroxycorticosterone
to aldosterone, the principal
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mineralocorticoid produced by the adrenal glands. The line denotes which steps occur outside the adrenal glands.