Dissociation of changes in growth hormone and adrenocortical hormone levels during brain stimulation of monkeys.

Abstract

Plasma concentrations of immunoreactive growth hormone (GH) and of 17-hydroxycorticosteroids (17OH-CS) were measured during electrical stimulation of hypothalamus or hippocampus in 6 conscious monkeys adapted to chronic restraint in primate chairs. Plasma GH and 17OH-CS increased during 13/14 hypothalamic stimulation experiments. During hippocampal stimulation, however, changes of plasma GH and 17OH-CS were variable. In 6 of 12 hippocampal experiments the qualitative change of plasma 17OH-CS differed from that of GH. These dissociated hormonal changes during hippocampal stimulation are evidence that the central neurological control systems for GH and ACTH are functionally distinct. When the GH and 17OH-CS changes were correlated with the behavior elicited by brain stimulation rather than with the site of stimulation, peak increases of GH, but not of 17OH-CS, were significantly greater during behavior characterized by pupillary dilatation or vigorous attempts to escape from the primate chair than during simple ‘alerting’ behavior. This suggests that plasma GH may reflect the intensity of the central excitatory state better than plasma 17OH-CS.