Endocrine Abstracts

Objectives

Polycystic ovary syndrome (PCOS) is the most common reproductive disorder that onsets peripubertally and increases morbidity by affecting quality of life. Insulin like peptide 5 (INSL5) is a relaxine/insulin family member gut-peptide hormone that is expressed by various tissues including the hypothalamus, pituitary and ovary. In the present study, we aimed to characterize serum INSL5 levels in PCOS women and determine association of circulating serum insulin like peptide 5 (INSL5) with serum AMH level, metabolic and hormonal parameters.

Materials and Methods

The present study included 45 women diagnosed with polycystic ovary syndrome between the ages of 18–35, who had not received medical treatment in the last six months, and 35 healthy women of the same age range as control group in Bolu Abant Izzet Baysal University School of Medicine, Department of Endocrinology and Metabolism. Anthropometric, hormonal, metabolic parameters and INSL-5 levels were determined in all patients. Pelvic ultrasonography was performed to examine ovarian size and follicle numbers.

Results

In the present study, INSL5 was 12.5 (3.8–59.5) ng/ml in the PCOS group and 15.5 (5.3–37.4) ng/ml in the control group. There was no statistically significant difference in terms of INSL5 between the groups (P = 0.103). INSL5 was negatively correlated with body mass index (BMI), free androgen index (FAI), insulin, HOMA-IR, triglyceride, total cholesterol, LDL, fat mass and positively correlated with sex hormone binding globulin (SHBG) in PCOS group. In multivariate linear regression analysis, FAI was significantly associated with serum INSL5 levels (β = –1.1, P = 0.015).

Conclusion

There was no statistically significant difference in INSL5 levels between PCOS patients and healthy subjects, suggesting that the peptide does not have a diagnostic value in PCOS. Negative correlation between INSL5 and FAI, insulin, HOMA-IR and atherogenic lipid profile supports the studies suggesting that this peptide might be related to glucose and lipid metabolism. In multivariate regression analysis, independent relationship of INSL5 with FAI indicates that further studies are required to evaluate the relationship between INSL5 and PCOS.

Key Words: PCOS, INSL5.