Considering gravitation as magnetic binding of (e-p) pairs, galactic systems are described in a fundamental theory based on a QED like Lagrangian with fermions coupled to boson fields. In this formalism severe boundary conditions have to be fulfilled, related to geometry, momentum and energy-momentum conservation. In this way all needed parameters are determined; thus giving rise to a description based on first principles. The primary process is magnetic binding of (e-p) pairs, leading to a very small binding energy of about 3 10−38 GeV and a first-order equivalent coupling constant, which is in agreement with Newton’s gravitational constant GN. Systems of magnetic binding of 10~100 (e-p) pairs (or hydrogen atoms) are related to galaxies. Their rotation velocities are well described, yielding information on the mass, the average particle density and the damping of coherent rotation. Different from the mass estimate derived from gravitation theory, the deduced galaxy masses show a rapid fall-off to smaller radii, which can be understood by the finiteness of these systems. No evidence has been found for galactic dark matter contributions.