In the current ex vivo study, we employed serum from GHR<sup>-/-</sup> mice, also known as LS mice (a model of GH resistance with high GH and low IGF-1 levels), and serum from bovine GH (bGH) transgenic mice (high GH and IGF-1), to test the effect on Trypanosoma cruzi infection. The gene discussed is IGF1; the disease is Chagas disease.