Frontiers in neuroendocrinology
-
Front Neuroendocrinol · Oct 1993
ReviewFeast and famine: critical role of glucocorticoids with insulin in daily energy flow.
The hypothesis proposed in this review is that normal diurnal rhythms in the hypothalamic-pituitary-adrenal (HPA) axis are highly regulated by activity in medial hypothalamic nuclei to effect an interaction between corticosteroids and insulin such that optimal metabolism results in response to changes in the fed or fasted state of the animal. There are marked diurnal rhythms in function of the HPA axis under both basal and stress conditions. The HPA axis controls corticosteroid output from the adrenal and, in turn, forward elements of this axis are inhibited by feedback from circulating plasma corticosteroid levels. ⋯ Lesions of the arcuate (ARC) and ventromedial (VMN) paraventricular (PVN) nuclei result in obesity and hyperactivity in the HPA axis. Moreover, adrenalectomy inhibits or prevents development of the lesion-induced obesity. There are interactions among these nuclei; one mode of communication is via inputs of neuropeptide Y (NPY) cells in the ARC to the VMN, dorsomedial nuclei, and PVN.(ABSTRACT TRUNCATED AT 400 WORDS)
-
Front Neuroendocrinol · Jan 1991
ReviewNeuroendocrine abnormalities in patients with traumatic brain injury.
This article provides an overview of hypothalamic and pituitary alterations in brain trauma, including the incidence of hypothalamic-pituitary damage, injury mechanisms, features of the hypothalamic-pituitary defects, and major hypothalamic-pituitary disturbances in brain trauma. While hypothalamic-pituitary lesions have been commonly described at postmortem examination, only a limited number of clinical cases of traumatic hypothalamic-pituitary dysfunction have been reported, probably because head injury of sufficient severity to cause hypothalamic and pituitary damage usually leads to early death. With the improvement in rescue measures, an increasing number of severely head-injured patients with hypothalamic-pituitary dysfunction will survive to be seen by clinicians. ⋯ Most severe injuries are sufficient to damage both structures and produce a mixed endocrine picture. Increased intracranial pressure, which releases vasopressin by altering normal hypothalamic anatomy, may represent a unique type of stress to neuroendocrine systems and may contribute to adrenal secretion by a mechanism that requires intact brainstem function. Endocrine function should be monitored in brain-injured patients with basilar skull fractures and protracted posttraumatic amnesia, and patients with SIADH or DI should be closely monitored for other endocrine abnormalities.