Within those two classes are five types according to the receptors to which they bind: glucocorticoids and mineralocorticoids (both corticosteroids) and androgens, estrogens, and progestogens (sex steroids).

[1][2] Vitamin D derivatives are a sixth closely related hormone system with homologous receptors.

Steroid hormones help control metabolism, inflammation, immune functions, salt and water balance, development of sexual characteristics, and the ability to withstand injury and illness.

[3][4][5] The natural steroid hormones are generally synthesized from cholesterol in the gonads and adrenal glands.

One study has found that these steroid-carrier complexes are bound by megalin, a membrane receptor, and are then taken into cells via endocytosis.

In order for steroid hormones to cross the lipid bilayer of cells, they must overcome energetic barriers that would prevent their entering or exiting the membrane.

These hormones, which are all derived from cholesterol, have hydrophilic functional groups at either end and hydrophobic carbon backbones.

Once in the nucleus, the steroid-receptor ligand complex binds to specific DNA sequences and induces transcription of its target genes.

However, all of these pathways are mediated by some type of steroid hormone receptor found at the plasma membrane.

[15] Ion channels, transporters, G-protein coupled receptors (GPCR), and membrane fluidity have all been shown to be affected by steroid hormones.