We study numerically the rheological properties of a slab of active gel close o the isotropic-nematic transition. The flow behavior shows strong dependence on sample size, boundary conditions, and on the bulk constitutive curve, which, on entering the nematic phase, acquires an activity-induced discontinuity at the origin. The precursor of this within the metastable isotropic phase for contractile systems ({em e.g.,} actomyosin gels) gives a viscosity divergence; its counterpart for extensile ({em e.g.,} {em B. subtilis}) suspensions admits instead a shear-banded flow with zero apparent viscosity.
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