The present invention provides a variety of useful polypeptides. Inparticular, a polypeptide comprising the same or substantially the same aminoacidsequence as the amino acid sequence represented by SEQ ID NO: 1, SEQ ID NO: 2or SEQ ID NO: 3, its amide, or a salt thereof can be used as an agent forpreventing/treating hypotension； an agent for preventing/treating obesity,hyperphagia, etc.； an agent for preventing/treating lethargy, time-zone changesyndrome (jet lag), etc.； an agent for preventing/treating sterility, etc. Acompoundor its salt that promotes the activity of a polypeptide comprising the same orsubstantially the same amino acid sequence as the amino acid sequencerepresentedby any of SEQ ID NOS: 7 to 12 and 37 to 42, its partial peptide, or a saltthereof isuseful as an agent for preventing/treating, e.g., menopausal symptoms orhyperthyroidism. A compound or its salt that inhibits the activity of saidpolypeptide is useful as an agent for preventing/treating, e.g., sterility orhypothyroidism.
