Arginine vasopressin in the testis: An intragonadal peptide control system

Abstract

The NEUROHYPOPHYSIAL hormones constitute a family of nonapeptides best known for their roles in the conservation of body water (antidiuretic effect) and the contraction of uterine (oxytocic effect) and vascular (pressor effect) smooth muscle. All the known naturally occurring neurohypophysial hormones of vertebrates (see Table 1) are endowed with a disulfide bridge (position 1–6) and display phylogenetic constancy for amino acids at positions 1, 5, 6, 7, and 9. In contrast, substitutions have occurred in the remaining amino acids thereby modifying biological activity and potency. While none of the neurohypophysial peptides is entirely selective in terms of its biological properties, one activity tends to predominate. Thus, peptides 1–5 (see Table 1) are predominantly antidiuretic and pressor active while peptides 6–11 are primarily oxytocic. Most species possess a characteristic pair of neurohypophysial peptides regulating antidiuretic and oxytocic activities. In most mammals, this pair is represented by arginine vasopressin (AVP) and oxytocin, respectively, whereas lysine vasopressin (LVP) assumes an antidiuretic role in the swine, peccary, and hippopotamus (1–3). Of the 11 known naturally occurring neurohypophysial hormones, only AVP and LVP occur exclusively in mammals (1–3); phenypressin has thus far been found only in marsupials (4). Isotocin, glumitocin, valitocin, and aspartocin are characteristic of nonmammalian species such as the shark (1–3). © 1986 by The Endocrine Society.