Adrenaline concentration and turnover in the arcuate nucleus and median eminence during the critical period in the rat

Abstract

Previous work has shown a relatively high turnover of adrenaline in the mediobasal hypothalamus during the critical period (15.00–17.00 h) of the proestrous rat. We now report that this high level of adrenergic activity can be detected in the median eminence (turnover rate1.62 ± 0.36pg/μg protein/h) rather than the arcuate nucleus (turnover rate0.18 ± 0.32pg/μg protein/h). In addition the median eminence was isolated as medial and lateral components and determination of catecholamine concentrations revealed a greater proportion of adrenaline (A) (59%) in the lateral median eminence whereas a larger proportion of dopamine (60%) was found in medial median eminence.