Abstract: Objective：To search the etiopathogenisis of db/db mice reproductive failure， which is supposed to be involved in the interaction of leptin and reproduction. Methods：Adult， female C57BL/6J mice were used in these studies. Littermate wide types（LR+），as well as diabetic （db/db）mutant genotypes（LR-），were matched for the allograft of the ovary. Different genotypic mice were constructed with body LR-，ovary LR+ in Group KO，as well as body LR+， ovary LR+ in Group WT，respectively（n=7）. The stage of cyclicity was determined by microscopic analysis of the predominant cell type in vaginal smears obtained daily，starting 2 weeks after transplantation，during two cycles. Mice in diestrus were decapitated. Blood was collected and centrifuged，and serum was stored for analysis of sex hormone and lipid profile. The ovaries were used to detect the levels of STAR，CYP 17，CYP 19，OB-RB，JAK 2，STAT 3，PIAS 3 and SOCS 3 mRNA. Results：Our results show that the mice displayed absent cycles in KO group，and the mice had normal cycles in WT group. The levels of E2，FSH，GLU，INS，CHO，LDL-C，body weight， fat weight and ovary weight as well as uterus weight were significant different in two groups. The ovarian mRNA expression of the STAR，CYP17 and CYP19 were lower in the KO group than in the WT group，but the expression of the OB-RB， STAT 3，PIAS 3，SOCS 3 mRNA were higher in the KO group than in the WT group. Conclusion：There were abnormal endocrine state in db/db mice（hyperglycaemia， hyperlipemia and lower gonadotropic hormone levels）. The abnormal state can down regulation the mRNA expression of the ovarian steroid synthetase and result the hyop-ovarianism. Ovary is not essential to whole glycometabolism and lipid metabolism.

Key words: Ovary, Transplantation, Ovarian function tests, Receptors, leptin, Mice, Signal transduction, Reproduction