When scientists break down the drug exendin-4 in a lab dish using rat liver bits, it mostly gets chopped at one specific spot, making a smaller piece called exendin-4(12–39).

When scientists studied a lab-made version of a hormone in rat kidney mixtures, they found it breaks apart at two specific spots, creating two smaller pieces as the first step in its breakdown.

In rats, the body breaks down a substance called exendin-4 differently in the kidneys and liver — the kidneys chop it up in several places early on, while the liver makes one main cut first and then trims the ends.

In lab tests with rat tissues, a substance called exendin-4 breaks down way faster in the kidney than in the liver — just a few minutes in the kidney versus over an hour and a half in the liver.

In rat tissues, certain enzymes probably break down a peptide called exendin-4, and scientists saw that blocking those enzymes slowed the breakdown in lab tests.