Intracrine refers to a hormone that acts inside a cell, regulating intracellular events. In simple terms it means that the cell stimulates itself by cellular production of a factor that acts within the cell. Steroid hormones act through intracellular (mostly nuclear) receptors and, thus, may be considered to be intracrines.
There are several protein/peptide hormones that are also intracrines. Notable examples that have been described in the references include:
- Peptides of the renin–angiotensin system: angiotensin II and angiotensin (1-7)
- Fibroblast growth factor 2
- Parathyroid hormone-related protein
See also Signal transduction.