Absence of sleep-related elevation of growth hormone level in patients with stroke

To determine the effect of defined suprahypothalamic lesions on sleep-related growth hormone (GH) secretion, eight patients with hemispheric lesions of vascular origin were studied in a sleep laboratory on two consecutive nights. Despite the normal onset and increased time spent in slow-wave sleep (SWS), the patients failed to show the nocturnal rise in plasma GH concentration that occurred in association with onset of SWS in five age-matched healthy subjects. Arginine hydrochloride infusion in the patients produced a normal GH rise, indicating integrity of the hypothalamic-pituitary axis. Dissociation between SWS and GH secretion in patients with suprahypothalamic damage suggests that cortical-subcortical structures are involved in the integration of SWS with nocturnal GH secretion. There is support for the presence of a thalamic regulatory center responsible for the control of GH release during sleep.