CHRONIC STRESS DOWN-REGULATES GROWTH-HORMONE GENE-EXPRESSION IN PERIPHERAL-BLOOD MONONUCLEAR-CELLS OF OLDER ADULTS

''Pituitary'' peptides are produced in both endocrine and immune cells . Acute and chronic stress can alter pituitary peptide secretion and m ight also influence neuroendocrine gene expression in human immune cel ls, We reasoned that, in Alzheimer caregivers, the chronic stress of c aregiving would impact on the sympathetic-adrenal-medullary and hypoth alamic-pituitary-adrenal axis possibly leading to alterations in GH mR NA in their peripheral blood mononuclear cells (PBMCs). Therefore, we evaluated 10 caregivers and 10 control subjects using a math and speec h stress protocol to determine their neuroendocrine profile and to eva luate any relationship with mononuclear cell GH mRNA levels simultaneo usly acquired and then evaluated by a quantitative competitive RT-PCR technique. We found a significant (p < .0001) decrease 50 % in GH mRNA levels in cells from caregivers. Plasma ACTH and norepinephrine level s were negatively correlated with GH mRNA levels, suggesting their pos sible role in the down-regulation of mononuclear cell CH gene expressi on. These observations support the hypothesis that experiences associa ted with caregiving alter the brain's autonomic nervous system and neu roendocrine control of the hypothalamic-pituitary axis. These and perh aps other influences may then produce altered GH gene expression in mo nonuclear cells of chronically stressed individuals. It is tempting to speculate that the decreased CH mRNA that we found in these chronical ly stressed caregivers was partially responsible for their poor respon se to influenza vaccine and their delayed wound healing.