List of contributors. G proteins and transmembrane signalling (L. Birnbaumer, J. Codina, R. Mattera, A. Yatani and A.M. Brown). Inositol phospholipids and cellular signalling (G.R. Guy and C.J. Kirk). The role of calcium binding proteins in signal transduction (N.C. Khanna, M. Tokuda and D.M. Waisman). Mechanism of action of Ca2+-dependent hormones (H. Rasmussen and P.Q. Barrett). Mechanism of action of pituitary hormone releasing and inhibiting factors (C. Denef). Mechanism of gonadotropin releasing hormone action (L. Jennes and P.M. Conn). The mechanisms of action of luteinising hormone. I. Luteinising hormone-receptor interactions (B.A. Cooke and F.F.G. Rommerts). The mechanisms of action of luteinising hormone. II. Transducting systems and biological effects (F.F.G. Rommerts and B.A. Cooke). Mechanism of action of FSH in the ovary (K.D. Dahl and A.J.W. Hsueh). The mechanism of ACTH in the adrenal cortex (P.J. Hornsby). Mechanism of action of angiotensin II (P.Q. Barrett, W.B. Bollag and H. Rasmussen). Mechanisms of action of glucagon (J.H. Exton). Mechanism of action of growth hormone (M. Wallis). Mechanism of action of prolactin (M. Wallis). Structure and function of the receptor for insulin (M.D. Houslay and M.J.O. Wakelam). A comparison of the structures of single polypeptide chain growth factor receptors that possess protein tyrosine kinase activity (W.J. Gullick). Subject Index.