possible to overload function in matlab class?

Is it possible to overload a function in a Matlab class that you've created?

Like the following:

    function [ sigma_nc ] = sustained_interference( N )
       sustained_interference( N, N.center_freq);
    end

    function [ sigma_nc ] = sustained_interference( N, center_freq )
       ...
    end

Unfortunately when I try this, I get a redefinition error