Atrial natriuretic peptide is synthesized in the human thymus.

Various neuropeptides have recently been isolated from the thymus, suggesting an interaction between the neuroendocrine and immune systems. We report here that the human thymus synthesizes a further peptide hormone, namely atrial natriuretic peptide (ANP). This is documented by the following findings. ANP and its prohormone were detected in thymic tissue by chromatographic analysis as well as by RIA; the thymus gland and, in particular thymocytes, contain mRNA coding for ANP. Since ANP is common to the brain and the immune system, these data support the notion of the existence of a neuroendocrine-immune axis.