role of ghrelin and ghrelin receptors in polycystic ovary syndrome

ABSTRACT

Polycystic ovary syndrome [PCOS] is related to obesity and to major metabolic alterations including both insulin resistance and beta-cell dysfunction. Ghrelin was identified as the endogenous ligand for the growth hormone secretagogue [GHS] receptor. The actions of ghrelin are carried out through interaction with specific receptor, named GHS-R. In a case-control study, we compared the expression of ghrelin and GHS-Rs mRNA by Quantitative Real-time PCR method in studied groups in order to determine the role of ghrelin and GHS-Rs in pathogenesis of PCOS. Follicular fluid samples were obtained at oocyte collection from 22 patients undergoing IVF-ET as control and 11 patients were diagnosed as having PCOS. Total RNA was extracted from isolated follicular fluid cells and 2[micro]g RNA was diluted and reverses transcribed using random primers and Superscript II. Specific primers for the ghrelin, GHS-R1a and GHS-R1b were designed. Samples were run in triplicate on an ABI Geneamp 5700 sequence detection system. They were subjected to 40 cycles of amplification under condition 92[degree]C- 20s and 62[degree]C-1min using 3[micro]l diluted cDNA [17], 10[micro]l 2X SYBR green, 3[micro]l diluted cDNA. [beta]-actin mRNA was assayed and then normalized to total RNA measurements for each sample. Age, weight and resulting pregnancies did not vary between PCOS and non-PCOS patients, whereas the BMI and serum testosterone level of PCOS were significantly higher than non-PCOS patients. Quantitative real-time RT-PCR showed that mRNA for ghrelin and GHS-R 1b were detectable in follicular fluid cells from all patients. We failed to find mRNA for GHS-R 1a in any of follicular fluid cells. There were no significant difference in ghrelin and GHS-R1b mRNA expression levels between PCOS and non-PCOS groups. Our findings indicate that ghrelin and ghrelin receptors may not be considered risk factors for pathogenesis of PCOS