Melatonin: Urine samples were collected for analyzing melatonin levels by measuring 6-sulfahydroxymelatonin (6-SMT) concentration, the major metabolite of the hormone in urine (de Almeida et al., 2011). The quantitative determination of 6-SMT in urine was completed by a solid phase enzyme-linked immunosorbent assay (ELISA # RE54031; IBL, Hamburg; Germany) as described previously (Zubidat & Haim, 2007). 6-SMT concentrations (ng/mL) were spectrophotometrically determined by ELISA microplate reader at 450 nm with reference wavelength 650 nm (PowerWave HT, Biotek, Winooski; USA) and analyzed by Gen5TM Data Analysis Software (Version 2, Biotek, Winooski; USA).