Each protocol started with a baseline period followed by the addition of the test substance applied either through the luminal tube or the vascular route
Zang M, Zuc collo A, Hou X, Nagata D, Walsh K, Herscovitz H, Brecher P, Ruderman NB, and Cohen RA: AMP-activated protein kinase is required for the lipid-lowering effect of metformin in insulin-resistant human HepG2 cells
14 Micronutrients Micronutrients are traditionally thought of as vitamins and minerals, but they also include individual metabolites, amino acids, and fatty acids
doi:10.1038/s41574-019-0275-6 Williams JA
The combination approach addresses multiple pathways of glucose dysregulation, making it effective for patients who don't reach target blood sugar on metformin or glipizide alone