Final answer:
Androgens like testosterone are transported in the bloodstream by Sex Hormone Binding Globulin (SHBG) which is produced by the liver.
Step-by-step explanation:
Leydig cells produce androgens, such as testosterone, which are steroid hormones derived from cholesterol. Because they are lipid-soluble, androgens rely on specific transport proteins for circulation in the bloodstream. These hormones are transported by a molecule known as Sex Hormone Binding Globulin (SHBG) or Testosterone Estradiol Binding Globulin (TEBG), which is made by the liver. The presence of SHBG allows testosterone and other steroid hormones to be carried effectively through the water-based bloodstream to their target tissues.