A NOVEL GLYCOPROTEIN IN THE OLFACTORY AND PITUITARY SYSTEMS OF LARVALAND ADULT LAMPREYS

A novel homodimeric glycoprotein was isolated and characterized from t he pituitaries of adult sea lampreys, Petromyzon marinus, modern repre sentatives of the earliest vertebrates. The monomer consists of 121 am ino-acid residues in a sequence that has no resemblance to any known p ituitary hormone. Whereas this protein is localized in most cells of t he rostral pars distalis of adult lampreys, we have chosen to name it, nasohypophysial factor (NHF), because it first appears in the olfacto ry system of developing larval lampreys. Not only may NHF be a new pit uitary hormone but a useful probe for examining the ontogenetic and ph ylogenetic relationships of the pituitary and olfactory systems in ver tebrates.