INS and hyperinsulinism: Since insulin secretion was not altered in the OLD mice compared with their controls (Figure 3A), the hyperinsulinemia observed in the former, after a glucose load (Figure 2B), could be due to an impaired hepatic insulin clearance as suggested by the lower c-peptide:insulin ratio, during the ipGTT (Figures 2C, D), in the OLD mice, compared with controls.