Aging pituitary function

The sympathetic nervous system (SNS) and the hypothalamic-pituitary axis work together as important modulators of the immune system after exposure to stressors. Norepinephrine (NE) and epinephrine (EPI) (catecholamines from the SNS) and neuroendocrine hormones modulate a range of immune cell activities, including cell proliferation, cytokine and antibody production, lytic activity, and migration. This chapter will focus on these two major pathways of brain-immune signaling, briefly summarizing the evidence for SNS and hypothalamic-pituitary-adrenal (HPA) modulation of immune function, their influence on immune-mediated diseases, immune modulation in aging, and early life influences on these pathways. 

The platyfish, a small freshwater teleost, has been studied intensively for more than 60 years (Kallman, 1975). Sufficient information has been amassed on its neuroendocrine system and on the hereditary mechanisms that control its age at sexual maturation, to make the platyfish invaluable for the study of the ontogeny, functioning and aging of the brain-pituitary-gonadal (BPG) axis. 

Prolactin-producing hypophyseal adenoma (prolactinoma) is the most common functional pituitary adenoma. Its prevalence peaks in women between 20 and 30 years of age. Hyperprolactinemia can be a cause of infertility and is associated with diminished gonadotropin secretion, secondary amenorrhea, and galactorrhea. The patient should first be examined for drug-induced hyperprolactinemia before any infertility work-up is initiated. For example, antidepressants, cimetidine, dopamine antagonists, reser-pine, sulpiride, verapamil, methyldopa, and estrogen therapy are known to interface with prolactin secretion. 

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