Activation of hormone receptors often initiates reactions that dampen the effects of that hormone. One of the first systems which was identified was the adrenergic beta receptor kinase or "ßark" reaction. Here, activation of the beta adrenergic receptor activates a kinase (ßark) that phosphorylates and inactivates the beta adrenergic receptor. A similar "feedback" effect is seen in the case of the insulin receptor. A family of proteins known as "suppressor of cytokine signaling" or SOCS bind to the insulin receptor substrate (IRS 1 and 2) and inhibit their activity. This is but one of the many feedback reactions controlling insulin signaling. Many of these are described in the article by Shepherd. A figure from that article is reproduced here. We can see that activation of the insulin receptor pathway not only activates metabolic enzymes etc., but also initiates "turn-off" reactions. The activated metabolic enzymes phosphorylate members of the signaling family and reduce their activity. Additionally, the SOCS gene is activated and SOCS (or SOCS3 here) is turned on and inhibits the insulin receptor. This diagram is quite complex but in no way underestimates the control mechanisms involved in insulin's action.