Wiktionary
n. (context steroid hormone English) A steroid prohormone involved in the steroidogenesis of progesterone, mineralocorticoids, glucocorticoids, androgens, and estrogens.
Wikipedia
Pregnenolone (3β-hydroxypregn-5-en-20-one), also known as P5, is an endogenous steroid hormone. It is the precursor of the progestogens, mineralocorticoids, glucocorticoids, androgens, and estrogens, as well as the neuroactive steroids. In addition, pregnenolone is biologically active in its own right, acting as a neurosteroid.
Usage examples of "pregnenolone".
Produced from cholesterol by way of pregnenolone, DHEA is an androgen that is metabolized to form androstenedione, which begets testosterone which begets estradiol and then estrone, and finally, estriol.
Estrogens and progesterone are just part of a complex and closely interlinked hormonal system that includes many other hormones, including testosterone, DHEA, pregnenolone, and melatonin, to name just a few.