Both electrical injection and detection of spin-polarized electrons are demonstrated in a single wafer all-semiconductor GaAs-based lateral spintronic device, employing p+-(Ga,Mn)As/n+-GaAs ferromagnetic Esaki diodes as spin aligning contacts. Spin-dependent phenomena, such as spin precession and spin-valve effect, are observed in nonlocal signal and the measurements reveal the unusual origin of the latter in the investigated devices. The conversion of spin-polarized holes into spin-polarized electrons via Esaki tunneling leaves its mark in a bias dependence of the spin-injection efficiency, which at maximum reaches the value of 50%.