Antioxidant Status and Serum Prolidase Activity in Women with Subclinical Hypothroidism

ABSTRACT

Purpose: Thyroid hormones are associated with the oxidant-antioxidant balance in the organism. Hypothyroidism is associated with impaired collagen turnover. We aimed to evaluate paraoxonase (PON) and arylesterase (ARE) activities, which prevent oxidative damage and serum prolidase activity (SPA) which is an important marker of collagen turnover  in premenopausal women with subclinical hypothyroidism (SH).
Material and Method: Eighteen women with SH (study group) and 18 age-sex-and body mass index-matched controls (control group) were enrolled. PON, ARE and SPA were determined.
Results: PON and ARE activities in the study group were significantly lower than in the control group (149.5 (56.2) U/L, 210.5 (161.2) U/L for PON, respectively; p=0.034 and 198.9 (28.6) U/L, 227.0 (101.3) U/L for ARE, respectively; p=0.044). The study group had significantly higher SPA than the control group (670.0 (9.7) U/L, 664.6 (8.2) U/L, respectively; p=0.027). TSH levels positively correlated with SPA (r=0.404, p=0.015) and PON and negatively with ARE (r=-0.348, p=0.037; r=-0.329, p=0.050, respectively).  
Discussion: Women with SH seem to have higher SPA and lower antioxidant enzyme activities when compared with healthy women which may cause an oxidant status in the organism. The underlying mechanisms and the significance of SPA in development of SH need to be further evaluated.