HMOX1 and type 2 diabetes mellitus: In the current study, we determined that the heme component of HA ameliorates hyperglycaemia in the db/db mouse model of type 2 diabetes; however, in contrast to previous research [3], we observed that concomitant administration of an inhibitor of HO activity, SM, does not abrogate the anti-diabetic effect of HA but rather accentuates it, indicating that the primary mode of action of heme is not via an increase in HO activity.