We are overwhelmed that our perspective clearly resonated with the audience
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])
Horiuchi Y, Wettersten N, Asami M, Yahagi K, Komiyama K, Yuzawa H, Tanaka J, Aoki J, Tanabe K (2025) Glucagon-like peptide-1 receptor agonists improve outcomes in individuals with type 2 diabetes with and without heart failure
Once that existing intake is laid out next to a new, higher protein target, it can feel genuinely mind-boggling, particularly when appetite is already reduced