However, it should also be recognized that it may be difficult to definitively demonstrate whether DPP-4 does play a physiologically relevant role in cleaving some endogenous substrates in vivo because it can be difficult to distinguish between the intact substrate and the truncated metabolite (because assays are not specific or sensitive enough) and/or because it may be difficult to obtain appropriate samples (e.g., from synapses [neurotransmitters] or interstitial fluid [paracrine signallers])
Bailey Bryan, Updated 2/17/2026 Shelly House, FNP, is a Family Nurse Practitioner and Call-On-Docs trusted medical education voice
BPC-157, also known as Body Protective Compound-157, has garnered attention for its regenerative properties
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Mihevc M, Petreski T, Maver U, Bevc S (2020) Renal proximal tubular epithelial cells: review of isolation, characterization, and culturing techniques