Our study investigated the relationship between insulin resistance (IR) and adiponectin expression in the adipose tissue of rat polycystic ovarian syndrome (PCOS) model. Female rats were divided into two equal groups according to their age, size and vitality. In Group 1, rats received subcutaneous injections of DHEA (once daily) for 20 consecutive days to induce PCOS, and those in Group 2 were injected with oil at the same period. Ovary weight, serum insulin and sex hormone levels were determined. Oral glucose tolerance test, light microscopy and electron microscopy were also performed. The adiponectin mRNA and protein in the adipose tissue were measured. The ovary weight in Group 1 was higher than that in Group 2 (p < 0.05). Numbers of follicular cysts and corpora lutea in group 1 were also significantly increased. The levels of serum testosterone and estradiol, fasting serum glucose and insulin were dramatically elevated when compared with those in Group 2 (p < 0.05). Additionally, the expression of adiponectin mRNA and protein was markedly down-regulated in the white adipose tissues of Group 1. The absence of adiponectin may play an important role in the pathogenesis of IR in PCOS, which makes adiponectin a promising therapeutic strategy in patients with IR induced by PCOS.

Key words: Polycystic ovarian syndrome, adiponectin, insulin resistance, sex hormone, animal model.