An androgen 'sex' hormone present in both males and females and responsible for differentiation including facial hair, deepening voices as well as a precursor for estrogen, Androstenedione (ANST) varies in the day and with women's cycles and is often measured when abnormal Testosterone or 17OHP results are found.
Excess levels can lead to ambiguous genitalia in children, excess body hair, and abnormal periods and early puberty. Adrenal tumors, ACTH-producing tumors, and adrenal hyperplasia can lead to the overproduction of androstenedione. Women with polycystic ovary syndrome (PCOS) may have higher levels of androstenedione. While elevated levels may not be noticed in adult men, they can lead to noticeable male physical characteristics (virilization) and a lack of monthly menstrual periods (amenorrhea) in females.