Pediatr Endocrinol Rev. 2004 Aug;1 Suppl 3:490-5.
A growing body of evidence indicates a bi-directional relationship between the neuroendocrine system and immune functions. It is well known that lymphoid organs such the thymus, the spleen and peripheral blood produce growth hormone (GH) and GH receptor is expressed on different subpopulations of lymphocytes. Many in vitro and in animal studies demonstrate an important role of GH in immunoregulation. GH stimulates T and B cells proliferation and immunoglobulin synthesis, enhances the maturation of myeloid progenitor cells and is also able to modulate cytokine response. However, in humans GH deficiency (GHD) is not usually associated with immunodeficiency and only minor abnormalities of immune function have been reported, as compared to those observed in GHD animals. It is possible that in humans the GH produced locally in the immune system compensates for the lack of endocrine GH. In this review the main actions of GH on the immune system in vitro, in animal models and in humans are summarized.
The pituitary gland and lymph organs, such as spleen, thymus, and peripheral blood, produce Growth hormone (GH). GH receptors are found on the surface of some lymphocytes. Previous studies have shown that GH has a function in the regulation of immunity and has been shown to have the following functions:
Surprisingly, human pituitary GH deficiency is not followed by immune deficiency. Perhaps, the local production of GH by lymph tissues compensates for the absence of pituitary GH and prevents the loss of immune function.
CONCLUSION: GH production by the lymph system in humans may prevent immune deficiency in people who have low production of pituitary GH. GH is known to have a number of immune functions and there is evidence in the studies for a clear relationship between the endocrine and immune systems.
NOTE: This summary was based on the PubMed abstract. The complete article is not available for review. Various GHRP and GHRH peptide have been shown to stimulate endogenous GH production.