  Phenomenological amplitudes obtained in partial-wave analyses (PWA) of
single-pion photoproduction are used to evaluate the contribution of this
process to the Gerasimov-Drell-Hearn (GDH), Baldin and
Gell-Mann-Goldberger-Thirring (GGT) sum rules, by integrating up to 2 GeV in
photon energy. Our study confirms that the single-pion contribution to all
these sum rules converges even before the highest considered photon energy, but
the levels of saturation are very different in the three cases. Single-pion
production almost saturates the GDH sum rule for the proton, while a large
fraction is missing in the neutron case. The Baldin integrals for the proton
and the neutron are both saturated to about four fifths of the predicted total
strength. For the GGT sum rule, the wide variability in predictions precludes
any definitive statement.
