SHORT PHOTOPERIOD REDUCES LEPTIN GENE-EXPRESSION IN WHITE AND BROWN ADIPOSE-TISSUE OF DJUNGARIAN HAMSTERS

Leptin gene expression in white (WAT) and brown adipose tissue (BAT) o f the Djungarian hamster (Phodopus sangorus) was analyzed during seaso nal acclimatization. Leptin gene expression in WAT was markedly reduce d during winter, independent of changes in environmental temperature. Exposure to artificial short photoperiod also decreased leptin gene ex pression in WAT as well as in BAT. Although specific leptin gene expre ssion was lower in BAT, total depot expression was as high as in WAT d epots, due to higher RNA content of BAT, Our results indicate that the re is significant leptin synthesis in brown fat and that leptin might be involved in photoperiod mediated seasonal adaptations of mammals in dependent of food deprivation or overfeeding.