Identification of neurohypophysial hormones with their antisera

Abstract

A B S T R A C T Identifying posterior pituitary hormones in body fluids or neurohypophysial extracts was heretofore partially achieved by using pharmacologic potency ratios or semispecific inactivation by thioglycolate or enzymes. Production of antisera against oxytocin and lysine-vasopressin has prompted us to test their specificity against lysine-vasopressin, arginine-vasopressin, arginine-vasotocin, and oxytocin. In ethanol anesthetized rats, antidiuretic and milk-ejection activities were assayed for each peptide-antiserum combination after 0, 30, 60, and 90 min of incubation. Results indicate that (a) oxytocin antiserum inactivates oxytocin, but not arginine-vasopressin, lysine-vasopressin, or arginine-vasotocin; vasopressin antiserum inactivates arginine-vasopressin and lysine-vasopressin, but neither oxytocin nor arginine-vasotocin; (b)) an identifiable antigenic site exists for each hormone; (c) relatively specific identifications of natural neurohypophysial peptides are possible using antisera and bioassays; (d) this method is promising for identifying neurohypophysial peptides in body fluids and pituitary extracts; and (e) active and passive immunization against oxytocin and vasopressin may increase our understanding of their physiologic functions.

Localization and Origin of Antidiuretic Principle in Para-Endocrine-Active Malignant Tumors

“…When vasopressin antiserum was diluted 1:10 with buffered physiologic saline of pH 7.4, and 0.1 ml of that dilution was incubated with ADH amounts of 200 ¡xU/ml, the antidiuretic activity was destroyed within 15 min of incubation, whereas in similar incubation procedures, the activity of oxytocin or arginine vasotocin remained intact [24]. Therefore, destruction of antidiuretic activity contained in a test sample after 30 min incubation with vasopressin antiserum indicates that this sample's activity is most likely due to ADH or a peptide very similar to it [23], Although in various tumor extracts antidiuretic and milk-ejection activities were measured -we have studied malignant tumors from over 20 different patients so far -the observed milk-ejection activity was never due to the effect of oxytocin.…”

“…Accordingly, antisera produced in rabbits against vasopressin or oxytocin are rather specific inactivators of the biologic activity of their respective hormone and are therefore suited for the biologic identification of neurohypophysial hormones [24].…”

Control of Release of Vasopressin by Neuroendocrine Reflexes

“…Does the converse occur? There is good evidence for independent release of vasopressin in response to hypovolaemia and hypotension. Increased concentrations of vasopressin in plasma without detectable oxytocin have been reported in response to haemorrhage in the cat (Beleslin, Bisset, Halder & Polak, 1967;Clark & Rocha e Silva, 1967), the rat (Ginsburg & Smith, 1959; Wakerley, Poulain, Dyball & Cross 1975;Poulain, Wakerley & Dyball, 1977), the dog (De Wardener, Fabian, Jones, Lee, Schrier & Verroust, 1968;Vorherr & Munsick, 1970) and the goat (McNeilly, Legros & Forsling, 1972). Although Fabian, Forsling, Jones & Lee (1969) detected release of oxytocin in the rat in response to haemorrhage, they noted that almost lethal bleeding was required to raise the plasma concentration significantly.…”

The Radioimmunoassay of Oxytocin and Vasopressin

“…Some of the antisera shown in Table 2 have been used for purposes other than radioimmunoassay. These include alternative immunological systems such as immunodiffusion (Hollander, Franz & Berde, 1966) and haemagglutination-inhibi¬ tion (Gusdon, 1967;Bashore, Jafek & Coblence, 1970), and the use of antisera to inhibit the biological activity of peptides and thus to enhance the specificity of a bioassay (Vorherr & Munsick, 1970). A notable feature in our own studies was the development of classical diabetes insipidus in one animal injected with carbonadsorbed arginine-vasopressin by the intra-lymph node route (Edwards et al 1972).…”