Multiple choice What is the primary function of Leydig cells of the testes? Regulating pituitary secretion of prolactin Inhibin secretion Nitric oxide release Testosterone synthesis Synthesis of androgen binding protein Reveal answer Fill a bubble to check yourself D Correct answer Explanation The primary function of Leydig cells is to synthesize and secrete testosterone. Leydig cells do this in a dose-dependent manner in response to LH.