Catecholamine turnover in the brain and the regulation of luteinizing hormone and corticosterone in starved male rats.

The effect of starvation was studied in male Wistar rats. After only 2 days of food deprivation, LH concentrations in serum are greatly suppressed, while a significant increase in plasma corticosterone occurs after 5 days' starvation. The noradrenaline and dopamine turnover in the basal hypothalamus is decreased after 2 days. The catecholamine turnover is also reduced in the preoptic area, and in the median eminence. Injection of the catecholamine precursor L-dopa (100 mg/kg) can prevent the increase of plasma corticosterone, but not the decrease of LH. The alpha-agonist clonidine (150 micrograms/kg), but neither the beta-agonist salbutamol (0.5 mg/kg), nor the dopamine agonist apomorphine (1.0 mg/kg) can prevent the starvation induced corticosterone increase. The decrease of plasma LH is not influenced by the dopamine or noradrenaline agonists. From these data, it appears that a decreased activity of noradrenergic neurons may be responsible for the corticosterone increase in the plasma of starved rats.