<prompt> Testosterone is secreted byGonadotropic cellsLeydigs cellsAcidophilic cellsSeoli cells  <response>: Testosterone C19 steroid with a hydroxyl group in the 17th position Testosterone is synthesized from cholesterol in the leydig cells by 17 alpha hydroxylase Testosterone is also formed androstenedione secreted by adrenal coexby 11 and 21 hydroxylases Secretion of testosterone is under the control of LH Rate of secretion of testosterone - 4-9mgdl in adult men Plasma testosterone level free and bound - 300- 1000ngdL in adult men 98 of testosterone in plasma is bound to protein 65 -bound to beta globulin gonadal steroid binding globulin sex steroid binding globulin and 33 bound to albumin Testosterone binds to an intracellular receptor The receptorsteroid complex then binds to DNA in the nucleus This facilitates the transcription of many genes In addition, testosterone is also conveed to Dihydrotestosterone by 5 alpha reductase in some target cells. DHT binds to the same intracellular receptor as testosterone Ref:- Ganongs Review of Medical Physiology 25th ed; pg num:- 422 