  Holst term represents an interesting addition to the Einstein-Cartan theory
of gravity with torsion. When this term is present the contact interactions
between vector and axial vector fermion currents gain an extra parity-violating
component. We re-derive this interaction using a simple representation for the
Holst term. The same representation serves as a useful basis for the
calculation of one-loop divergences in the theory with external fermionic
currents and cosmological constant. Furthermore, we explore the possibilities
of the on-shell version of renormalization group and construct the equations
for the running of dimensionless parameters related to currents and for the
effective Barbero-Immirzi parameter.
