  We perform a calculation of the isospin and hypercharge axialvector current
propagators to two loops in SU(3)xSU(3) chiral perturbation theory. A large
number of order p^6 divergent counterterms are fixed, and complete two-loop
renormalized expressions for the pion and eta masses and decay constants are
given. The calculated isospin and hypercharge axialvector polarization
functions are used as input in new chiral sum rules, valid to second order in
the light quark masses. Some phenomenological implications of these sum rules
are considered.
