Getting value of the field instead of sys_id

I have a script where I do a GlideRecord query to the request table. Once I get the records, I am getting to the value of the opned by field. But since opened by is a reference field, it is returning sys_id. How can I get the displayed value ?

Below is the script :

var gr = new GlideRecord("sc_req_item");
gr.addQuery("u_requested_for", g_form.getValue("emp_name"));
gr.addQuery("stage",'!', "waiting_for_approval");
gr.query();

if(gr.next())
{
alert("A request has already been submitted by " + gr.opened_by); // this is returming sys_id, I need the value

}


Please let me know if anyone has any suggestions.