One class of internal transport barrier discharge in the JT-60Utokamak is characterized by two relatively flat regions of thepressure separated by a region with very large pressure gradient.Linear growth rates for toroidal drift type modes are calculated fordischarges in this class, without and with sheared E×B rotation effects. For cases with fully developed barriers, theresults with rotation are consistent with a picture in which theradial electric field generated in part by the steep pressure gradientcauses local stabilization, and thus reduction of the local anomaloustransport, which allows the steep pressure gradient to persist. Ifrotation is omitted from the calculation for these cases, or ifrotation is included for cases without barriers or with partiallydeveloped barriers, the unstable region spreads into the steeppressure gradient region.