It was aimed to compare circulating levels of ghrelin, leptin, peptide YY (PYY), and neuropeptide (NPY) between girls with idiopathic central precocious puberty (ICPP) and prepubertal girls, as well as to evaluate alterations in these hormone levels and body composition during leuprolide acetate treatment in girls with ICPP. The gene discussed is PYY; the disease is precocious puberty.