Although selenium is known to be essential for reproductive function, studies have indicated the adverse effect with its prolonged use. The present study investigated the duration-related effect of selenium administrations on reproductive hormones and estrous cycle indices in adult female Wistar rats exposed to a model of light pollution using altered photoperiod (AP). Ninety-six cyclic female Wistar rats displaying 4–5 days' estrous cycle length (ECL) and weighing 148–152 g were randomly divided into short and long experimental cohorts consisting of six groups each and spanning for 1 and 8 weeks, respectively. Each consisted of control, high selenium dose (HSE), low selenium dose (LSE), AP, AP + HSE, and AP + LSE. The rats were orally administered high dose (150 μg/kg) and low dose (100 μg/kg) of sodium selenite once per day. The estrous cycle indices were monitored. Plasma levels of follicle-stimulating hormone, luteinizing hormone (LH), estradiol (E), progesterone (P), prolactin, E/P ratio, and histology of ovary and uterine horn were evaluated. The statistical analysis was performed using Statistical Package for the Social Sciences. In AP rats, HSE and LSE caused no significant effect on LH, E, P, and E/P ratio, ECL, estrus interval (EI), and estrous cycle ratio (ECR). The effect of HSE and LSE on LH, E, P, E/P ratio, and ECL showed no duration-dependent increase, but there was a duration-dependent increase in EI and ECR at low dose. The study indicated that administration of HSE of selenium improved reproductive function in photo-pollution-exposed rats irrespective of the duration of treatment.

BACKGROUND: Night-time study is a routine practice exhibited by public university and college students in Nigeria most especially before and during end of semester examination period. AIM AND OBJECTIVES: We investigated the impact of pre-examination night-time study frequency on sleep pattern, peripheral oxygen saturation (SPO2) and anthropometrical indices in age-matched Nigerian female students. MATERIALS AND METHODS: 60 age-matched female subjects who emerged from simple random sampling were classed into irregular and regular night study groups using Visual Analogue Scale Questionnaire. Measurements of SPO2, pulse rate (PR), weight and height were done using pulse oximeter, weighing scale and meter rule respectively. Insomnia index (IN) and Day-time Sleepiness Indices (DS) were determined using sleep quality scale. RESULTS: Regular night-time study has no significant effect (P<0.05) on SPO2, PR and DS when compared with irregular night-time study group. However, students who reported regular night-time study exhibited significantly higher (P<0.05) IN, body weight and body mass index (BMI) when compared with irregular night-time study group. There was a positive correlation between IN and BMI (r=0.269, P<0.05). Pulse rate also negative correlated with SPO2 (r=-0.280, P<0.05) and BMI (r=-0.342, P<0.05). Pulse rate also negative correlated with SPO2 (r=-0.280, P<0.05) and BMI (r=-0.342, P<0.05). CONCLUSION: The results of the study indicated that female students undergoing regular night-time study prior to examination exhibited higher body weight, body mass index and insomnia index.