Mouse OPG, RANKL, and GAPDH mRNAs were semi- quantified by RT-PCR. Hepatic total RNA was reverse- transcribed using ReverTraAce®, and then cDNA was amplified under the conditions recommended by the supplier (Invitrogen®). The conditions of PCR cycle were followed by the method of Siggelkow et al. [19] with some modifications. After separation of the PCR products by 2% agarose gel electrophoresis, the target cDNA were detected under ultraviolet light in the presence of ethidium bromide and semi-quantified by Syngene gel documenta- tion (Ingenius L, Cambridge, UK) and the GeneTools match program.