Thymulin (also known as thymic factor or its old name facteur thymique serique) is a

nonapeptide Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. A ...

produced by two distinct epithelial populations in the

thymus The thymus is a specialized primary lymphoid organ of the immune system. Within the thymus, thymus cell lymphocytes or ''T cells'' mature. T cells are critical to the adaptive immune system, where the body adapts to specific foreign invaders. ...

first described by Bach in 1977. It requires

zinc Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...

for biological activity. Its

peptide sequence Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. A ...

is H-Pyr-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn-OH. The hormone is believed to be involved in

T-cell A T cell is a type of lymphocyte. T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell r ...

differentiation and enhancement of T and NK cell actions. Besides this rather paracrine or auto-organic effects on the thymus dependent immune system, thymulin seems to have neuroendocrine effects as well. There exist bidirectional interactions between thymic epithelium and the hypothalamus-pituitary axis (for example, thymulin follows a circadian rhythm and physiologically elevated

ACTH Adrenocorticotropic hormone (ACTH; also adrenocorticotropin, corticotropin) is a polypeptide tropic hormone produced by and secreted by the anterior pituitary gland. It is also used as a medication and diagnostic agent. ACTH is an important c ...

levels correlate positively with thymulin plasma levels and vice versa). A recent focus has been on the role of thymulin as an effector on proinflammatory mediators/ cytokines. A peptide analog of thymulin (PAT) has been found to have analgesic effects in higher concentrations and particularly neuroprotective anti-inflammatory effects in the CNS.

Astrocytes Astrocytes (from Ancient Greek , , "star" + , , "cavity", "cell"), also known collectively as astroglia, are characteristic star-shaped glial cells in the brain and spinal cord. They perform many functions, including biochemical control of endo ...

seem to be the target for thymulin for this effect. Researchers hope to develop drugs thwarting inflammatory processes associated with neurodegenerative diseases and even rheumatism with the help of thymulin analogs. Moreover, thymulin has been associated with

anorexia nervosa Anorexia nervosa, often referred to simply as anorexia, is an eating disorder characterized by low weight, food restriction, body image disturbance, fear of gaining weight, and an overpowering desire to be thin. ''Anorexia'' is a term of Gr ...

References

{{Neuropeptides Peptides

See also

References