Endocrinology/Adrenal hormones

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Contents 1 Synthetic pathways 1.1 Zona glomerulosa 1.2 Zona fasciculata 2 Regulation 2.1 Renin-angiotensin system 2.2 Atrial natriuretic peptide 2.3 Glucocorticoids

Synthetic pathways

Zona glomerulosa

• Synthesizes mineralocorticoids (chiefly aldosterone and 11-deoxycorticosterone)
• Lacks 17α-hydroxylase
• Has 18-hydroxylase (enhanced by renin-angiotensin system)
• Has 18-hydroxydehydrogenase (enhanced by renin-angiotensin system)

Zona fasciculata

• Synthesizes glucocorticoids (chiefly cortisol and corticosterone)
• Has lots of 17α-hydroxylase (which is why we have more cortisol than corticosterone)
• Lacks 18-hydroxylase
• Lacks 18-hydroxydehydrogenase

Regulation

Renin-angiotensin system

• AII, AIII, and K⁺ → ↑P450_SCC (cholesterol → pregnenolone)
• AII, AIII, and K⁺ → ↑18-hydroxylase, ↑18-hydroxydehydrogenase (corticosterone → aldosterone)
• AII, ↑Na⁺, ↑BP → ↓renin

Atrial natriuretic peptide

• Produced mainly from right atrium of heart in response to stretch
• ANP → ↓renin in juxtaglomerular cells
• ANP → ↓aldosterone synthesis
  • ANP → ↓P450_SCC
  • ANP → ↓18-hydroxylase

Glucocorticoids

• Glucocorticoids → ↑dopamine β-hydroxylase → ↑catecholamines (NE, Epi, DA)
• Glucocorticoids → ↓ACTH (only glucocorticoids do this)