A method is provided of decreasing or increasing the activity of a Pappalysin polypeptide by decreasing or increasing the level of interacting Pappalysin and stanniocalcin polypeptides. A method is also provided of preventing, treating or ameliorating a clinical condition in a mammalian subject, such as a human being, said method comprising administering to said mammalian subject, such as human being an effective amount of a stanniocalcin polypeptide. Moreover, a method is provided of preventing, treating or ameliorating a clinical condition in a mammalian subject, such as a human being, said method comprising administering to said mammalian subject, such as human being an effective amount of an agent capable of antagonizing interaction of a stanniocalcin polypeptide with a Pappalysin polypeptide.