“…Several studies, aimed at determining which region of PRL interacts with the receptor, have been reported. Sequence comparisons (Nicoll et al, 1986;Luck et al, 1989), chemical modifications (Doonen and Bewley, 1979;Andersen and Ebner, 1979;Necessary et al, 1985;de la Llosa et al, 1985; for review, see Nicoll et al, 1986) or mutational studies (Luck et al, 1989(Luck et al, , 1990(Luck et al, , 1991Goffin et al, 1992) characterized some structural features potentially involved in the biological properties of PRL but none of these data unequivocally localized the global PRL binding site.…”