The present invention relates to an inhibitor of Hairy and Enhancer of Split 3 (Hes3) for use in a method of preventing or treating (i) a disease characterised by insulin resistance or (ii) obesity. Further, the present invention also relates to a method of preventing or treating a disease characterised by insulin resistance or obesity, to a pharmaceutical composition comprising Hes3 and to Hes3 and/or an activator thereof for use in a method of preventing or treating a disease characterised by decreased insulin production. In addition, the present invention relates to a method of preventing or treating a disease characterised by decreased insulin production and to the use of Hes3 as a target in a screen for identifying a compound suitable as a lead compound and/or as a medicament for the treatment of diseases characterised by insulin resistance or of obesity or of diseases characterised by decreased insulin production. Moreover, the present invention relates to in-vitro or ex-vivo methods for identifying a compound suitable as a lead compound and/or as a medicament for the treatment and/or prevention of diseases characterised by insulin resistance or of obesity or of diseases characterised by decreased insulin production. Finally, the present invention also relates to an in-vitro method of eliciting or enhancing insulin production.
