Glutathione S-transferase (GST) polymorphism could be an early marker in the development of polycystic ovary syndrome (PCOS) - an insight from non-obese and non-insulin resistant adolescents.
Parole chiave
Astratto
BACKGROUND
It has been supposed that endocrine disturbances might be responsible for polycystic ovary syndrome (PCOS)-associated oxida-tive 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 normoinsulinemic adolescent girls newly diagnosed with PCOS.
METHODS
Nitrotyrosine, 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, insulinogenic index (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 nitrotyrosine concentrations correlated with testosterone, DHEAS, androstenediones, FAI, and LH, while changes in thiol groups cor-related 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 androsten-edione, it can be suggested that increased free radical production, probably as a consequence of hyperandrogenaemia, is an early event in the development of PCOS.
