GC-MS-based metabolic signatures reveal comparative steroidogenic pathways between fetal and adult mouse testes

Abstract

Background Previous studies on gonadal steroidogenesis have not compared metabolic pathways between fetal and adult mouse testes to date. Objectives To evaluate comparative metabolic signatures of testicular steroids between fetus and adult mice using gas chromatography-mass spectrometry (GC-MS)-based steroid profiling. Materials and methods GC-MS with molecular-specific scan modes was optimized for selective and sensitive detection of 23 androgens, 7 estrogens, 14 progestogens, and 13 corticoids from mouse testes with a quantification limit of 0.1-5.0 ng/mL and reproducibility (coefficient of variation: 0.3%-19.9%). Based on 26 steroids quantitatively detected in testes, comparative steroid signatures were analyzed for mouse testes of 8 fetuses on embryonic day 16.5 and 8 adults on postnatal days 56-60. Results In contrast to large amounts of steroids in adult testes (P < .0002), all testicular levels per weight unit of protein were significantly increased in fetal testes (P < .002, except 6 beta-hydroxytestosterone ofP = .065). Both 11 beta-hydroxyandrostenedione and 7 alpha-hydroxytestosterone were only measurable in fetal testes, and metabolic ratios of testosterone to androstenediol and androstenedione were also increased in fetal testes (P < .05 for both). Discussion and conclusion Testicular steroid signatures showed that both steroidogenic Delta(4)and Delta(5)pathways in the production of testosterone were activated more during prenatal development. Both 7 alpha- and 11 beta-hydroxylations were predominant, while hydroxylations at C-6, C-15, and C-16 of testosterone and androstenedione were decreased in the fetus. The present GC-MS-based steroid profiling may facilitate understanding of the development of testicular steroidogenesis.