Variable rest masses in 5-dimensional gravitation confronted with experimental data

Cosmological solutions of Einstein equation for a \mbox{5-dimensional} space-time, in the case of a dust-filled universe, are presented. With these solutions we are able to test a hypothetical relation between the rest mass of a particle and the $5^{\mathrm{t}\mathrm{h}}$ dimension. Comparison with experiment strongly refutes the implied dependence of the rest mass on the cosmological time.