INS and Insulin resistance: Nevertheless, fasting insulin at 7 months tended to be lower in the MET exposed male offspring (P = 0.08, Table 2) and HOMA-β index calculated based on the fasting glucose and insulin level implicated that prenatal metformin exposure alleviated insulin resistance in the OE-NPYDβH male offspring during WD (HOMA-β index P < 0.05, Table 2).