Copeptin as a Marker and Vitamin D as a Protector to Some Metabolic and Hormonal Changes in Both Lean and Obese Polycystic Ovary Syndrome Rat Model

Abstract

Background: Polycystic ovary syndrome (PCOS) is one of the most common causes of female infertility. It is commonly linked to insulin resistance (IR), obesity, hyperlipidaemia, and type II diabetes. Copeptin has been linked to insulin resistance and the development of atherosclerosis. There have been some debates about copeptin levels and their relationship to hormonal and metabolic changes in PCOS. Vitamin D deficiency is common in PCOS and may contribute to the disease's pathophysiology.

Aim of the work: The purpose of this study was to estimate serum copeptin levels in letrozole-induced PCOS in both lean and obese female rats, as well as to investigate the relationship between serum copeptin levels and some metabolic and hormonal parameters in PCOS, as well as to determine the effect of vitamin D administration on different groups and its relationship to PCOS with copeptin serum levels.

 Material and Methods: This study included 64 young virgin female albino rats of the local strain. They were divided into eight equal groups: lean control, lean PCO, lean vitamin D supplemented, lean PCO supplemented with vitamin D, obese control, obese PCO, obese vitamin D supplemented, and obese PCO supplemented with vitamin D. For 7 weeks, lean groups were fed standard laboratory chow, while obese groups were fed a high-fat chow. PCO groups were induced by orally supplementing with letrozole (Daily 0.5 mg/kg dissolved in water by oral gavage) for 21 days, and vitamin D groups were supplemented orally for 70 days.

Fasting serum copeptin, luteinizing hormone (LH), follicular stimulating hormone (FSH), testosterone, estradiol, progesterone, insulin, glucose, triglycerides, cholesterol, low density lipoprotein LDL, and high-density lipoprotein HDL levels were measured. In addition, at the end of the experiment, all groups had their BMI and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) calculated.

Results: When compared to both lean and obese control groups, serum copeptin levels were significantly higher, while vitamin D levels were significantly lower in both lean and obese PCOS groups. Furthermore, when compared to the lean PCOS group, the obese PCOS group had significantly higher levels of copeptin and lower levels of vitamin D. Furthermore, there was a significant positive correlation between serum copeptin and BMI, insulin, glucose, HOMA IR, cholesterol, TG, LDL, VLDL, LH, and testosterone. It had a significant inverse relationship with Vitamin D, HDL, Progesterone, and estrogen. Supplementing with vitamin D improved insulin sensitivity, dyslipidaemia, and some hormonal changes in PCOS.

Conclusion:  Copeptin is associated with many metabolic and hormonal changes accompanying polycystic ovary syndrome and may have a role in the development of this disorder and associated comorbidities. In addition, Vitamin D is negatively correlated with copeptin and its deficiency is linked to PCO, so vitamin D maybe a suitable supplement to prevent the associated cardiometabolic disorders in PCOS in both lean and obese.