Hormonal Alterations in Prepubertal Children with Iron Deficiency

Dear Editor; The study“Serum Levels of Ghrelin, Leptin, IGF-I, IGFBP-3, Insulin, Thyroid Hormones and Cortisol in Prepubertal Children with Iron Deficiency” authored by Isguven et al. was published in Endocrine Journal in 2007 [1]. We read the article with great interest. However, we noticed that it contained several scientific errors. We, authors, would like to make the following comments on the study in general, and its methodology and thus the discussion part in particular. Peptide-structure hormones, including ghrelin, are broken down by proteases in biological fluids [reviewed 2, 3]. In order to overcome this problem, Hosoda et al. published a standardized collection method for ghrelin in 2004 [4]. Therefore, the researchers had to prevent ghrelin breakdown by using a protease inhibitor. This very important pre-analytical mistake shall affect both the results and the discussion part. Ghrelin is found in two major forms as acylated and desacylated in biological fluids [reviewed 2, 3].