FGF1 and obesity due to melanocortin 4 receptor deficiency: ,12 Systemic administration of recombinant FGF1 results in various metabolic improvements, including acute normalization of blood glucose levels and a reduction in hepatic steatosis and inflammation upon prolonged treatment.[12], [13], [14] FGF1 can bind to all FGF receptors and acts independently of the FGF19/FGF21 coreceptor β-Klotho, which may be transcriptionally downregulated in adipose tissue and the liver during obesity.15