If one were to take up to 500mg/week of testosterone enanthate based on a trt style blast and cruise regiment for a long duration (say 5 years), would recovery of the Hypothalamic-pituitary-gonadal axis be possible?
Yes, but the result might not be what you like.
If you did not support the testes with low dose hCG or low dose SERM and the testes are small, the outlook is grim.
General TRT info: https://tnation.T-Nation.com/free_online_forum/sports_training_performance_bodybuilding_trt/prototype_advice_for_new_guys
Restart specific: https://tnation.T-Nation.com/free_online_forum/sports_training_performance_bodybuilding_trt/hpta_restart_for_trt_guys_with_application_to_gear_and_pct