What is the Origin of Lipid Diffusion?

This term is derived from cellular biology, combining "lipid" (referring to the fatty nature of the cell membrane and the diffusing molecule) and "diffusion" (the passive spread of molecules). It describes a basic physical principle governing membrane permeability.

What is the Mechanism of Lipid Diffusion?

Since steroid hormones like testosterone and estrogen are lipophilic, they can easily dissolve within the hydrophobic core of the plasma membrane. They traverse the membrane to bind to intracellular receptors, often located in the cytoplasm or nucleus. This binding initiates a cascade that modulates gene transcription and protein synthesis, which is the ultimate action of these hormones on the cell.

Lipid Diffusion ∞ Area

Lipid Diffusion

Meaning

Lipid diffusion is a fundamental process of passive transport where lipid-soluble molecules, such as steroid hormones, move directly across the cell’s lipid bilayer membrane without the aid of membrane proteins. This movement occurs down the concentration gradient, allowing for the rapid and unhindered entry of fat-soluble signals into target cells. It is the primary mechanism by which steroid hormones exert their genomic effects.