MC4R
MC4R melanocortin 4 receptor — the molecular target that 2 compounds in the wiki act on.
In one line: The brain receptor that controls both appetite and sexual desire.
MC4R is a receptor deep in the brain that, surprisingly, governs two different things: how full you feel, and sexual desire. Press it in the appetite centre and hunger drops; press it in the desire circuits and libido rises.
This is why two very different drugs both target it: setmelanotide treats a rare genetic obesity by pressing the "fullness" side, and PT-141 (an approved libido drug) works on the "desire" side — acting in the brain, unlike Viagra-type drugs that work on blood flow.
It's a neat example of how one molecular target can have completely different uses depending on where in the brain it's activated.