Impact of maternal melatonin suppression on amount and functionality of brown adipose tissue (BAT) in the newborn sheep

Abstract

© 2014 Seron-ferre, Reynolds, Mendez, Mondaca, Ebensperger, Valenzuela, Valenzuela, Herrera, Llanos and Torres-farfan. In human and sheep newborns, brown adipose tissue (BAT) accrued during fetal development is used for newborn thermogenesis. during gestation on the amount and functionality of BAT in the neonate. We studied BAT from 6 lambs gestated by ewes exposed to constant light from 63% gestation until delivery to suppress melatonin (LL), 6 lambs gestated by ewes exposed to LL but receiving daily oral melatonin (12mg at 1700 hrs, LL+Mel) and another 6 control lambs gestated by ewes maintained in 12h light:12h dark (LD). Lambs were instrumented at 2 days of age. At 4-6 days of age, they were exposed to 24°C (thermal neutrality conditions) for 1 hr, 4°C for 1 hr and 24°C for 1 hr. Afterward, lambs were euthanized and BAT was dissected for mRNA measurement, histology and ex vivo experiments. LL newborns had lower central BAT and skin temperature under thermal neutrality and at 4°C, a