We investigated changes in the IL-1 alpha, IFN-gamma and IL-4 release from splenocytes in the presence of growth hormone (GH). Splenocytes were stimulated with Protein A (PA), Toxic Shock Syndrome Toxin-1 (TSST-1) and Streptolysin S (SLS). In the presence of GH, splenocytes stimulated with PA, induced a 40% and 50% drop in IL-1 alpha and IFN-gamma release respectively, compared to controls, while no changes were shown in IL-4 release. The release of IFN-gamma by TSST-1-stimulated splenocytes fell by 30%, while no changes were shown in IL-1 alpha and IL-4 release after GH. The release of IL-1 alpha by SLS-stimulated splenocytes increased by 50% in the presence of GH. No changes were shown in IFN-gamma and IL-4 release. The results are discussed in terms of the possibility of an expanding function for these endocrine peptides within the immune system.