Q: In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.
It is synthesized in the magnocellular neurons of the supraoptic and paraventricular nuclei, and its secretion is triggered by stimulation of the organum vasculosum, the subfornical organ, or the area postrema. Commonly found in excess in the urine of those individuals with a chromophobe adenoma, its two major forms differ only with the presence of either a lysine or an arginine. The essential feature of diabetes insipidus is the lack of this hormone or a blocking of its action. This octapeptide, like oxytocin, is produced in the hypothalamus and stored in the posterior pituitary gland. FTP, name this hormone that acts on the kidneys to retain water and reduce urine output.
A:
Science