HCAR1 and familial pancreatic carcinoma: Additionally, lactate within the microenvironment can also be sensed by GPR81, a Gi-coupled receptor on the pancreatic cancer membrane, promoting the expression of MCTs and CD147. In addition, activated GPR81 upregulates peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) and increases mitochondrial biogenesis and respiration.