Green tea polyphenols inhibit testosterone production in rat Leydig cells

Asian J Androl. 2009 May;11(3):362-70. doi: 10.1038/aja.2009.2. Epub 2009 Mar 30.

Abstract

This study investigated the acute effects of green tea extract (GTE) and its polyphenol constituents, (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin (EC), on basal and stimulated testosterone production by rat Leydig cells in vitro. Leydig cells purified in a Percoll gradient were incubated for 3 h with GTE, EGCG or EC and the testosterone precursor androstenedione, in the presence or absence of either protein kinase A (PKA) or protein kinase C (PKC) activators. The reversibility of the effect was studied by pretreating cells for 15 min with GTE or EGCG, allowing them to recover for 1 h and challenging them for 2 h with human chorionic gonadotropin (hCG), luteinizing hormone releasing hormone (LHRH), 22(R)-hydroxycholesterol or androstenedione. GTE and EGCG, but not EC, inhibited both basal and kinase-stimulated testosterone production. Under the pretreatment conditions, the inhibitory effect of the higher concentration of GTE/EGCG on hCG/LHRH-stimulated or 22(R)-hydroxycholesterol-induced testosterone production was maintained, whereas androstenedione-supported testosterone production returned to control levels. At the lower concentration of GTE/EGCG, the inhibitory effect of these polyphenols on 22(R)-hydroxycholesterol-supported testosterone production was reversed. The inhibitory effects of GTE may be explained by the action of its principal component, EGCG, and the presence of a gallate group in its structure seems important for its high efficacy in inhibiting testosterone production. The mechanisms underlying the effects of GTE and EGCG involve the inhibition of the PKA/PKC signalling pathways, as well as the inhibition of P450 side-chain cleavage enzyme and 17beta-hydroxysteroid dehydrogenase function.

MeSH terms

  • Androstenedione / pharmacology
  • Animals
  • Camellia sinensis*
  • Chorionic Gonadotropin / pharmacology
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • Flavonoids / pharmacology*
  • Gonadotropin-Releasing Hormone / pharmacology
  • Humans
  • Leydig Cells / drug effects*
  • Leydig Cells / metabolism*
  • Male
  • Phenols / pharmacology*
  • Plant Extracts / pharmacology*
  • Polyphenols
  • Protein Kinase C / metabolism
  • Rats
  • Rats, Wistar
  • Signal Transduction / drug effects
  • Testosterone / metabolism*

Substances

  • Chorionic Gonadotropin
  • Flavonoids
  • Phenols
  • Plant Extracts
  • Polyphenols
  • Gonadotropin-Releasing Hormone
  • Testosterone
  • Androstenedione
  • Cyclic AMP-Dependent Protein Kinases
  • Protein Kinase C