Exposures to Artificial Light at Night (ALAN) is on the increase with resultant
varied physiological impact related to the light spectrum via the non-visual
pathway. This study examined the effects of various spectra of ALAN on
Testosterone (Te), Progesterone (Pr) and Estradiol (Es) in rats exposed to Blue
(BL), Green (GL), Yellow (YL), Red (RL), White (WL) and Darkness (DD)
light wave-lengths while Ambient light (CL) served as the control. Dams with
their post-natal day 1 pups were housed in cages exposed to various light
wavelengths for 12 hours: (6:00pm–6:00am) daily for 126 days. At d₆₃ and d₁₂₆,
five rats per treatments were euthanized; blood serum was collected and the
serum hormones: Te, Es and Pr were analysed using ELISA. The results
showed that light treatments had significant effect on the level of Te at d ₆₃ but
not at d126 in male rats. At d₆₃, onset of puberty, Te was significantly highest (p
< 0.05) under BL. In females exposed to YL and WL at d₁₂₆, Te was significant
high and Es was significantly low. Estradiol was heightened significantly (p <
0.05) in both sexes exposed to RL. In conclusion, BL seemed to stimulate early
sexual development in males, WL and GL enhanced post-pubertal male albino
rat reproductive system while RL provided the best reproductive environment
for females in the long term. Long periods of exposure to YL seemed to pose
risks for male and female reproductive function.