Androstenedione (Synonyms: 4-Androstene-3,17-dione)

Androstenedione is an endogenous weak androgenic steroid hormone produced in the adrenal glands and gonads and is an intermediate in the biosynthesis of estrone and testosterone^[1]. Androstenedione is a common precursor of both androgenic and estrogenic sex hormones^[2]. Androstenedione can be biosynthesized in one of two ways. The primary pathway involves the conversion of 17α-hydroxypregnenolone to dehydroepiandrosterone (DHEA) by 17,20-lyase, followed by the conversion of DHEA to androstenedione by 3β-hydroxysteroid dehydrogenase. The secondary pathway involves the direct conversion of 17α-hydroxyprogesterone (usually a precursor of cortisol) to androstenedione by 17,20-lyase^[3]. Androstenedione is manufactured as a dietary supplement and is believed to increase testosterone levels, enhance athletic performance, build body muscle, reduce fat, increase energy, maintain healthy red blood cells, and improve sexual performance^[4]. Serum androstenedione levels greater than or equal to 200 ng/dL may indicate the presence of adrenal or gonadal tumors^[5].

In vivo, oral administration of androstenedione (60 mg/kg/day) to pregnant and non-pregnant female rats induced a significant increase in the formation of 6α-, 15β-, 7α-, 16β-, and 2β-hydroxytestosterone in the liver cells of pregnant and non-pregnant rats^[6]. Androstenedione (1.5-100 mg/kg) administered as a 21-day sustained-release granule to ovariectomized rats reduced cancellous bone volume loss in a dose-dependent manner by reducing bone turnover^[7].

References:
[1] Elzenaty R N, Du Toit T, Flück C E. Basics of androgen synthesis and action[J]. Best Practice & Research Clinical Endocrinology & Metabolism, 2022, 36(4): 101665.
[2] Tang J, Chen L R, Chen K H. The utilization of dehydroepiandrosterone as a sexual hormone precursor in premenopausal and postmenopausal women: an overview[J]. Pharmaceuticals, 2021, 15(1): 46.
[3] Miller W L. Androgen synthesis in adrenarche[J]. Reviews in Endocrine and Metabolic Disorders, 2009, 10(1): 3-17.
[4] Badawy M T, Sobeh M, Xiao J, et al. Androstenedione (a natural steroid and a drug supplement): a comprehensive review of its consumption, metabolism, health effects, and toxicity with sex differences[J]. Molecules, 2021, 26(20): 6210.
[5] Yesiladali M, Yazici M G K, Attar E, et al. Differentiating polycystic ovary syndrome from adrenal disorders[J]. Diagnostics, 2022, 12(9): 2045.
[6] Flynn T J, Sapienza P P, Wiesenfeld P W, et al. Effects of oral androstenedione on steroid metabolism in liver of pregnant and non-pregnant female rats[J]. Food and chemical toxicology, 2005, 43(4): 537-542.
[7] Lea C K, Moxham V, Reed M J, et al. Androstenedione treatment reduces loss of cancellous bone volume in ovariectomised rats in a dose-responsive manner and the effect is not mediated by oestrogen[J]. Journal of endocrinology, 1998, 156(2): 331-340.