PPARG and type 2 diabetes mellitus: Various 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acids, including 3-(5-fluorofuryl)-substituted derivatives 21(a,b), were synthesized and evaluated for their ability to partially activate peroxisome proliferator-activated receptor gamma (PPARγ), which plays a key role in lowering the blood sugar level in patients with type 2 diabetes [183].