No, TRT causes the hypothalamus to shut down its production of GnRH (gonadotropin releasing hormone). Without that, the pituitary gland stops releasing LH. Without LH the testicles stop making testosterone and the Leydig cells that produce test go to sleep and your nuts shrink. HCG mimics LH.
DHEA and preg are hormones that simply are part of the natural pathways your body follows. With age and exogenous test, this decreases and can cause issues with energy, libido, anxiety, stress, sleep, and memory. When you backfill with pregnenolone, it is like flipping an on switch to all this (other than anxiety, which it obliterates).