Role of brain catecholaminergic system in hypothalamic obesity in rats

Distribution of labelled catecholamines (CA) was studied after intraventricular injection of 3H-norepinephrine (NE) and 3H-dihydrozyphenylalanine (DOPA) in several brain regions of ventromedial hypothalamic lesioned female rats. After intraventricular infection of 3H-NE a decrease in endogenous NE content and a marked increase in labelled NE concentration were observed in the preoptic-basal cortical area and lateral hypothalamus, while no change was found in these parameters in brain areas caudal to the lesion. The 3H-DOPA uptake of preoptic-basal cortical area and also the lateral hypothalamus was lower. No change was found in the uptake of 3H-DOPA in the corpus striatum. These results support the hypothesis that the decreased function of noradrenergic pathways in the medial forebrain bundle plays a role in the development of hypothalamic obesity without any concomitant functional changes in the striatal dopaminergic system.