Key points are not available for this paper at this time.
It is shown that for electromagnetic waves the gravitational field of a rotating body acts as an optically active medium. Thus, the plane of polarization of the wave rotates while it passes through this field. The effect is small. The angle of rotation due to the gravitational field of the sun is about 10^-12 radian.
N. L. Balázs (Tue,) studied this question.