AIMTo study the effect and mechanism of gonadotrophin-releasing hormone (GnRH) on murine Leydig cell steroidogenesis.

METHODSPurified murine Leydig cells were treated with GnRH-I and -II agonists, and testosterone production and steroidogenic enzyme expressions were determined.

RESULTSGnRH-I and -II agonists significantly stimulated murine Leydig cell steroidogenesis 60%-80% in a dose- and time-dependent manner (P < 0.05). The mRNA expressions of steroidogenic acute regulatory (StAR) protein, P450scc, 3beta-hydroxysteroid dehydrogenase (HSD), but not 17alpha-hydroxylase or 17beta-HSD, were significantly stimulated by both GnRH agonists with a 1.5- to 3-fold increase (P < 0.05). However, only 3beta-HSD protein expression was induced by both GnRH agonists, with a 1.6- to 2-fold increase (P < 0.05).

CONCLUSIONGnRH directly stimulated murine Leydig cell steroidogenesis by activating 3b-HSD enzyme expression.

3-Hydroxysteroid Dehydrogenases ; biosynthesis ; genetics ; Animals ; Blotting, Western ; Cell Separation ; Cells, Cultured ; Cholesterol Side-Chain Cleavage Enzyme ; biosynthesis ; Dose-Response Relationship, Drug ; Gonadotropin-Releasing Hormone ; agonists ; pharmacology ; Leydig Cells ; drug effects ; metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Phosphoproteins ; biosynthesis ; genetics ; RNA ; biosynthesis ; isolation & purification ; Reverse Transcriptase Polymerase Chain Reaction ; Sexual Maturation ; physiology ; Steroids ; biosynthesis ; Testosterone ; biosynthesis