Growth hormone and cognitive function.

Emerging data indicate that growth hormone (GH) therapy could have a role in improving cognitive function. GH replacement therapy in experimental animals and human patients counteracts the dysfunction of many behaviours related to the central nervous system (CNS). Various behaviours, such as cognitive behaviours related to learning and memory, are known to be induced by GH; the hormone might interact with specific receptors located in areas of the CNS that are associated with the functional anatomy of these behaviours. GH is believed to affect excitatory circuits involved in synaptic plasticity, which alters cognitive capacity. GH also has a protective effect on the CNS, as indicated by its beneficial effects in patients with spinal cord injury. Data collected from animal models indicates that GH might also stimulate neurogenesis. This Review discusses the mechanisms underlying the interactions between GH and the CNS, and the data emerging from animal and human studies on the relationship between GH and cognitive function. In this article, particular emphasis is given to the role of GH as a treatment for patients with cognitive impairment resulting from deficiency of the hormone.