The in vitro biosynthesis of epitestosterone and testosterone from C19 steroid precursors in the testis of the lizard Tiliqua rugosa

Journal Article · Tue Aug 01 00:00:00 EDT 1989 · General and Comparative Endocrinology; (USA)

DOI:https://doi.org/10.1016/0016-6480(89)90081-6· OSTI ID:5131670

Huf, P A; Bourne, A R; Watson, T G ^[1]

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1. Deakin Univ., Geelong, Victoria (Australia)

The metabolism of androgens in the testis of the lizard Tiliqua rugosa has been studied in vitro by incubating cellular homogenates with radiolabeled C19-steroid substrates. The identification 17 beta-oxidoreductase and 3 beta-hydroxysteroid dehydrogenase/isomerase activities. Aromatase, 5 alpha-reductase, and 17 alpha/beta-epimerase activities were not detected. The 17 alpha-oxidoreductase activity was temperature dependent (maximal at 32 degrees), while the 17 beta-oxidoreductase activity was temperature independent. Time yield and dual-label studies indicated that testosterone biosynthesis mainly involves the 4-ene pathway (via androstenedione), whereas the formation of epitestosterone uses both the 4-ene and 5-ene (via 5-androstene-3 beta, 17 alpha-diol) pathways. The function of alternative pathways in androgen biosynthesis is discussed, as is the role of temperature in the intratesticular regulation of androgen production.

• OSTI ID: 5131670
• Journal Information: General and Comparative Endocrinology; (USA), Vol. 75:2; ISSN 0016-6480
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ANDROGENS
METABOLISM
TESTOSTERONE
BIOSYNTHESIS
BIOLOGICAL PATHWAYS
CARBON ISOTOPES
ENZYME ACTIVITY
ISOMERASES
LIZARDS
OXIDOREDUCTASES
TEMPERATURE DEPENDENCE
TESTES
TRACER TECHNIQUES
TRANSFERASES
TRITIUM COMPOUNDS
ANDROSTANES
ANIMALS
BODY
ENZYMES
GONADS
HORMONES
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
KETONES
MALE GENITALS
ORGANIC COMPOUNDS
ORGANS
REPTILES
STEROID HORMONES
STEROIDS
SYNTHESIS
VERTEBRATES
550501* - Metabolism- Tracer Techniques