Evaluating hypothalamic gnrh mRNA expression during different stages of the estrous cycle in a rat model of polycystic ovary syndrome

Background: Polycystic ovary syndrome (PCOS) is a frequent endocrine and metabolic disorder and the most common cause of infertility occurring in 5% to 10% of women of reproductive age. PCOS animal models showed elevated GnRH/LH pulse frequency. This may result from a number of mechanisms, including alterations in synaptic input to GnRH neurons, desensitization of GnRH neurons to steroid feedback, increased amplitude/frequency of GnRH pulses, and increased gonadotroph sensitivity to the GnRH stimulation.Methods: RNAs were extracted from hypothalamus of prenatally androgenized (PNA) and non-PNA female rats thought estrus cycle. The gnrh mRNA, gonadotropin and steroid hormone levels, was tested using Cyber-green Real-time PCR and ELISA methods, respectively.Result: Hypothalamic gnrh mRNA levels was different during estrous cycle, with the highest expression level at the proestrous stage in both groups. In addition PNA rats showed higher gnrh levels at the diestrous than control group. The PNA rats, also, showed disrupted hormonal profile compared to control group.Conclusion: This study time, investigated the hypothalamic gnrh mRNA expression during different stages of estrous cycle. We demonstrated that the pattern of expression of gnrh mRNA in PNA rats was similar to the pattern in the control group except at the diestrous. PNA rats exhibited higher gnrh levels at the diestrous than control group, which may reflect endocrine abnormalities associated with PCOS phenotype.

کلیدواژه ها:

Gene Expression ، GNRH/LH surge ، Prenatal androgenization ، steroid feedback ، PCOS