1. Dipartimento di Scienze Morfologiche e Biochimiche Comparate, Universita' degli Studi di Camerino, 62032 Camerino, Italia; and
2. Laboratory of Cellular and Molecular Endocrinology, European Institute for Peptide Research, Institut National de la Santé et de la Recherche Médicale U413, UA CNRS, University of Rouen, France