Endothelin-2

Where it comes from

Made in

Ovary (granulosa cells at ovulation), intestine, kidney

Sent out by

A sharp burst in the follicle just before it ruptures

Acts on

• Follicle wall
• Gut and kidney vessels
• Retina

What it does

• Contracts the follicle wall to release the egg, in mice ¹
• Constricts vessels like endothelin-1, with no measurable difference at either receptor ³
• Takes part in the retina’s response to light damage, as the signal stressed photoreceptors send to the glia around them ²

In medicine

• It has no medicine of its own, and no human disease has been traced to EDN2; the endothelin receptor blockers used in lung and kidney disease bind the receptors it shares with endothelin-1 ³
• Two residues separate the two peptides, and at ETA and ETB that difference does not show, so a pharmacologist treats them as one target ³
• Antibodies and assays cross-react between them, so a measurement reported as endothelin-1 may include endothelin-2; how much is not known ³

Beyond the body’s own use

• Mice whose granulosa cells cannot make endothelin-2 fail to rupture their follicles and ovulate poorly. That is the main reason anyone asks whether endothelin blockers could affect fertility, and no human study has tested it ¹
• In the injured retina, photoreceptors switch on EDN2 and signal to the surrounding glia; it is used in animal work as a marker of photoreceptor stress rather than as a treatment target ²
• Nothing is in trials and nothing is claimed for it. The open question is whether a peptide this close to endothelin-1 has any job that is truly its own