Use of a cross-species immunohistochemical procedure to demonstrate the presence of neurophysin antibodies in the serum of a patient treated with pitressin

Serum from a patient who had been treated with Pitressin for extended periods was evaluated for the presence of autoantibodies. When this immune serum was used with either an immunofluorescence or an heterologous immunoperoxidase technique, positive staining was observed in the neurophysin-containing cells of the rat supraoptic, paraventricular and suprachiasmatic nucleus. Whereas the immune serum may also be expected to contain antibodies against oxytocin, vasopressin and the anterior pituitary hormones, this could not be substantiated with the immunohistochemical procedures.