Isolation of a Tridecapeptide from Natriuretic Fractions of Bovine Posterior Pituitary

Abstract

PMgUe, Ci%XhOdOveki8Abafrad. Crude Van Dyke protein prepared from frozen bovine posterior pituitary glands WBB treated with formic acid to reletme small bound and &orbed peptides. Gel filtration, continuous free-flow eledrophoreais and descending paper electrophoresis were need to separate the amall ptides into successively purer fractions which were a m a x f o r preaeor, uterotonk, natriuretic and mehnocyte stimdating acthitien under double blind conditions. The higheat peak of natriuretio activity was ~eeociated with ody 8 small premor and no uterotonic activities, and the name fractions contained a ninhydrin-positive spot on paper electrophoresis, the mobility stimulating hormone (MSH) and A(;TH-( 1-13-amide)-tridecapeptide (1-13 ACI'H-amide) but differed fmm v wpreaein and oxytocin. Material from this spot had an amino Of Which a t pH 5.6 W8d Simik that Of 8lph8-mel8mCyte acid composition which comsponded with the first 13 residues of ACI'H. Qoantitativs biosMsy of the fins1 fraction in the frog demonstrated a melanotropic sctivity which, however, wan lower than would have been expected for p m alpha-MSH.The natriuretic activity of the isolated fraction wan far higher than the potency of separately adminiatemd peptidee which might be present ' ' e-vampreasin, alpha-MSH or 1-13 mixture of alpha-biSH and 1-13 A m , and that alpha-MSH may be an scetylsted end-product of ACI!H cleavage in the pituitary.Key wor&: A(;TH fragments, alpha-MSH, natriuretic peptiden, natriuretic hormone. ACTH. It is s n g g 2 3 -that the isolated fraction represents aThere is an extensive literature over the past decade concerning the appearance of a natriuretic activity in blood plesma and urine during natriuretic states in many mammalian species, induced by such stimuli as: saline, dextran or blood infusion, carotid occlusion, etc. The physiological evidence has been reviewed

Sympathetic nervous system mediation of acute cardiovascular actions of gamma 2-melanocyte-stimulating hormone.

“…These decreases in renal blood flow were followed by 5 to 70 mm Hg increases in MAP. The remaining five rats were much less responsive to intrarenal arterial injection of y 2 …”

Natriuretic and hypertensive activities reside in a fragment of ACTH.

“…We investigated the effects of a fragment of this hormone (ACTH pressor and cardioaccelerator actions sympathetic nervous system R ECENT evidence from our laboratories suggests that it is possible for a single substance to regulate renal sodium excretion (a natriuretic hormone [NH]) and have cardiovascular effects. 1 ' 2 Investigators searching for a NH have isolated alpha-melanocyte-stimulating hormone (aMSH) and a fragment of adrenocorticotrophic hormone (ACTH 1 " 13 ) from pituitaries 3 based on their natriuretic activity 4 and on affect of salt loading on pituitary aMSH. 4 Another pituitary peptide with natriuretic activity is /3MSH, 5 now thought to be a product of beta-lipotrophin (/3LPH).…”

Interaction of Vasopressins and Linear N‐Terminal ACTH Fragments in the Induction of Natriuresis

“…This programme yielded : a) from both source materials a consistent natriuretic maximum in close correlation to vasopressin-containing fractions, b) from the bovine material a peptide containing the first 13 residues of ACTH, the electrophoretic mobility of which was close to that of arginine-vasopressin (AVP) and c) no single, new molecule of high, specific natriuretic activity [13]. Two extraction programmes were initiated for natriuretic peptides from the posterior pituitary, one starting from porcine pituitrin (an acetone dry powder of whole posterior glands) the other from crude Van Dyke protein-small peptide complex prepared from frozen bovine posterior lobes.…”