Kisspeptin-13

Where it comes from

Made in

Isolated from human placenta with the 54- and 14-residue forms

Sent out by

With kisspeptin-54

Acts on

• GnRH neurons

What it does

• Full activity at the receptor: it was isolated from placenta with the other two and binds as tightly ¹
• Differs from kisspeptin-14 by a single residue at the front, so no antibody raised against the shared tail can tell the two apart
• Short-lived in blood, as all the kisspeptins are

In medicine

• None of its own. The trials and the diagnostic infusions use kisspeptin-54 or kisspeptin-10 ²
• A kisspeptin level measured in pregnancy or in research counts every length together, including this one

Beyond the body’s own use

• It exists because the long peptide is trimmed from the front, and each piece keeps the amidated tail the receptor reads ¹
• No trial has given it to people. The only head-to-head work in humans compared the 10 and the 54 and found them much alike ²
• How much of the placenta’s output circulates as the shorter forms is not known, and that is the open question for all three of them