The Effects of Daylight Exposure on Melatonin Levels, Kiss1 Expression, and Melanoma Formation in Mice.

Aim To determine how daylight exposure in mice affects melatonin protein expression in blood and Kiss1 gene expression in the hypothalamus. The second aim was to as sess the relationship between skin cancer formation, day-light exposure, melatonin blood level, and kisspeptin gene expression level. Methods New-born mice (n = 96) were assigned into the blind group or daylight group. The blind group was raised in the dark and the daylight group was raised under 12 hours light/12 hours dark cycle for 17 weeks. At the end of the 11th week, melanoma cell line was inoculated to mice, and t timor growth was observed for 6 weeks. At the end of the experiment, melatonin level was measured from blood serum a rid Kiss1 expression from the hypothalamus. Results The blind group had significantly higher meta tonin and lower Kiss1 expression levels than the daylight group. Tumor volume was inversely proportional to melatonin levels and directly proportional to Kiss1 expression levels. Tumor growth speed was lower in the blind than in the daylight group. Conclusion Melatonin and Kiss1 were shown to be nvolved in tumor suppression. They were affected by daylight and were mutually affected by each other.