Green tea polyphenols inhibit testosterone production in rat Leydig cells / 亚洲男科学杂志(英文版)
Asian Journal of Andrology
;
(6): 362-370, 2009.
Article
in English
| WPRIM
| ID: wpr-284677
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.
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Pharmacology
/
Phenols
/
Testosterone
/
Flavonoids
/
Protein Kinase C
/
Plant Extracts
/
Signal Transduction
/
Gonadotropin-Releasing Hormone
/
Rats, Wistar
/
Cyclic AMP-Dependent Protein Kinases
Limits:
Animals
/
Humans
/
Male
Language:
English
Journal:
Asian Journal of Andrology
Year:
2009
Type:
Article
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