Figure 1. Mechanisms of metformin action inside the target cell. Metformin is transported into the cells through organic cation transporters (OCTs). Inside the cell, it inhibits complex 1 of mitochondrial respiratory chain, mitochondrial glycerol-3-phosphate dehydrogenase (mGPD) and AMP deaminase (AMPD), and stimulates the formation of AMPK heterotrimeric (αβγ) complex. Metformin can inhibit mammalian target of rapamycin complex 1 (mTORC1) through AMPK activation or through RAG GTPase inhibition. Green arrows denote stimulatory action while red arrows denote inhibitory action.
