IRS1 and steatosis: On the other hand, deletion of Irs2 led to the impaired insulin signalling in the PP zone, where Irs1 expression is relatively low and thereby the contribution of Irs2 is relatively greater, leading to the impaired suppression of gluconeogenesis and hyperglycaemia, whereas in the PV zone, where Irs1 expression is relatively high, insulin signalling was maintained despite Irs2 deletion, resulting in steatosis.