Δ4-Androstenedione

Δ4-Androstenedione (also known as 4-Androstenedione, Androst-4-ene-3,17-dione, or simply Androstenedione) is a 19-carbon steroid hormone that is a natural precursor in the biosynthesis of the androgen and estrogen sex hormones. It is produced in the gonads, adrenal glands, and adipose tissue.

Structure and Nomenclature

Δ4-Androstenedione is a steroid with a double bond at the 4th carbon position. The term "Δ4" refers to the presence of this double bond. The name "Androstenedione" is derived from "Andro" (meaning male or masculine) and "stene" (meaning narrow or slender), with "dione" indicating the presence of two keto groups at the 3rd and 17th positions.

Biosynthesis

Δ4-Androstenedione is synthesized from cholesterol through a series of enzymatic reactions. The process begins with the conversion of cholesterol to pregnenolone by the enzyme P450scc. Pregnenolone is then converted to progesterone by 3β-HSD. Progesterone is converted to 17α-Hydroxyprogesterone by 21-hydroxylase, which is then converted to Androstenedione by 17,20 lyase.

Function

Δ4-Androstenedione serves as a key intermediate in the production of androgen and estrogen sex hormones. It can be converted to testosterone by the enzyme 17β-HSD, or to estrone by the enzyme aromatase.

Clinical Significance

Abnormal levels of Δ4-Androstenedione can be indicative of various medical conditions. Elevated levels may be seen in congenital adrenal hyperplasia, polycystic ovary syndrome, and adrenocortical carcinoma. Reduced levels may be seen in hypogonadism and Addison's disease.

See Also

• Androgen
• Estrogen
• Steroid hormone
• Biosynthesis
• Congenital adrenal hyperplasia
• Polycystic ovary syndrome
• Adrenocortical carcinoma
• Hypogonadism
• Addison's disease