GLOSSARY

Steroid hormones are fat-soluble hormones derived from cholesterol with a four-ring structure (the sterane nucleus); made in the adrenal cortex, gonads, and placenta, they regulate gene expression via intracellular receptors.

Groups

• Glucocorticoids: cortisol; glucose metabolism, the stress response, and anti-inflammation.
• Mineralocorticoids: aldosterone; sodium and potassium balance and blood pressure.
• Androgens: testosterone, DHT, and DHEA; male characteristics and anabolism.
• Oestrogens: oestradiol, oestrone, and oestriol; female characteristics and bone health.
• Progestogens: progesterone; the menstrual cycle and pregnancy.
• Vitamin D (calcitriol) also has a secosteroid structure.

Synthesis (Steroidogenesis)

• Cholesterol → pregnenolone (by P450scc in the mitochondria, the rate-limiting step; cholesterol delivered by the StAR protein).
• Then different enzymatic pathways in each tissue lead to cortisol, aldosterone, androgens, or oestrogens.

Characteristics