One approach incorporates ligands into drug formulations to enhance their selective uptake in target tissues.

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That would allow Arena to target the hundreds of so-called orphan GPCRs that have no known ligands.

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One example is a treatment of obesity: Inside Takeda laboratories are test animals that are very slim thanks to pills developed based on one of these ligands.

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Drugmakers looked for proteins called ligands, which dock to specific GPCRs, and then created a drug that either blocked or enhanced the ability of the ligand to connect with its receptor.

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Researchers there have focused on something called orphan ligands.

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