Glutathione S-transferase (GST) polymorphism could be an early marker in the development of PCOS: An insight from non-obese and non-insulin resistant adolescents

Abstract

Introduction: It has been supposed that endocrine disturbances might be responsible for PCOS-associated oxidative stress, with special emphasis on hyperandrogenism. Considering the potential relationship between hyperandrogenism and increased free radical production, parameters of oxidative stress were determined in non-obese normoinsulinaemic adolescent girls newly diagnosed with polycystic ovary syndrome (PCOS). Materials and methods: Nitrotyrosin, thiol group concentrations, glutathione peroxidase, and superoxide dismutase activities were determined under fasting conditions and during oral glucose tolerance test (OGTT) in 35 PCOS patients and 17 controls. Insulin resistance was assessed by the homeostasis model (HOMA-IR), HOMA β, IGI, Matsuda insulin sensitivity index (ISI), and AUC for glucose. Glutathione S-transferases (GSTs) polymorphisms were determined by PCR. Results: Under fasting conditions, no significant difference of oxidative stress parameters was found between PCOS and controls. Acute hyperglycaemia during OGTT induced significant alteration in parameters of oxidative protein damage in PCOS patients. Alteration in nitrotyrosin concentrations correlated with testosterone, DHEAS, androstenediones, FAI, and LH, while changes in thiol groups correlated with DHEAS. Significant inverse association was found between LH and ISI, as well as AUC glucose and thiol groups. PCOS girls, carriers of GSTM1-null genotype, had significantly lower testosterone in comparison to ones with GSTM1-active genotype. Conclusions: PCOS girls exhibited high free radical production together with unchanged antioxidant enzymatic capacity, independently from obesity and insulin resistance. Based on associations between oxidative stress parameters and testosterone, DHEAS, and androstenedione, it can be suggested that increased free radical production, probably as a consequence of hyperandrogenaemia, is an early event in the development of PCOS. © 2018 Via Medica.All right reserved.