Chapter 21. Peptide Hormones of the Hypothalamus and Pituitary

Abstract

Publisher Summary This chapter describes the biological activities and therapeutic application of peptide hormones of the hypothalamus, pituitary, and neurohypophyseal hormones. The hypothalamus hormones discussed are gonadotropin releasing hormone (GNrH), melanotropin release-inhibiting factor (MIF) and melanotropin releasing factor (MRF), somatostatin, and thyrotropin releasing hormone (TRH). GnRH might be expected to find diagnostic, prophylactic, and therapeutic applications in human and animal fertility. One problem facing in vivo applications is the short duration of action of GnRH. The significance and physiological roles of peptides, which exhibit H-Pro-Leu-Gly-NH2 (MIF) or MRF activities are still subjects of debate because of great experimental difficulties with bioassays. Concerning biosynthetic aspects, however, the enzymatic formation of MIF from oxytocin was the first example, on a molecular basis, of a well-defined peptide hormone serving as a precursor or second order prohormone for a smaller peptide with entirely different hormonal activities. The pituitary hormones discussed in this chapter are adrenocorticotropin and melanotropin, growth hormone and prolactin, and glycoprotein hormones (follicle stimulating hormone, luteinizing hormone, and thyroid stimulating hormone).