Developmental changes in long-form leptin receptor expression and localization in rat brain

The expression and localization of long-form leptin receptor (OBRb) were studied immunocytochemically in the brain of fetal and adult rats using a polyclonal antibody that specifically recognized OB-Rb. At 14 days of gestation, immunoreactive cells were observed in the ventricular layer, which contains premature neuronal cells. At 18 days of gestation, they were weakly stained but obvious in the paraventricular nucleus (PVN), and ependymal cells also showed immunoreactivity. At birth, the immunoreactivity of OB-Rb in the PVN seemed to be much lower than that in adult rats and remained low during the suckling period. Considering the presence of neuroendocrine and structural neuronal abnormalities in Lep(ob)/Lep(ob) mice with genetic leptin deficiency, these results suggest that the expression of OB-Rb in premature neuronal cells may have some function, and that the regulation of energy balance by leptin through hypothalamic regions, such as PVN, may not yet be developed in the perinatal period.