Cortisol and GH responses to D- and L-amphetamine in monkeys.

Equimolar doses of D-amphetamine and L-amphetamine, and a water placebo were injected intravenously on different days into rhesus monkeys, and their plasma cortisol and GH responses were determined over a 3-hour period. D- and L-amphetamine (but not the placebo) equally suppressed plasma cortisol concentration and equally increased plasma GH concentration. Pretreatment of the monkeys with large doses of pimozide, a specific dopamine receptor blocker, did not appear to block the hormonal responses to either isomer of amphetamine. The results suggest that the hormonal responses to both D- and L-amphetamine were mediated by noradrenergic neurones stimulatory to GH and inhibitory to ACTH, and that D- and L-amphetamine exert equipotent noradrenergic effects in the neuroendocrine system.