Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

A Sensitive Hydroosmotic Toad Bladder Assay. Affinity and intrinsic activity of neurohypophyseal peptides

Journal Article · · Journal of General Physiology
DOI:https://doi.org/10.1085/jgp.52.3.465· OSTI ID:1629142
 [1];  [2];  [2]
  1. City Univ. of New York (CUNY), NY (United States). The Mount Sinai Medical and Graduate Schools. Dept. of Physiology; Brookhaven National Lab. (BNL), Upton, NY (United States). The Medical Research Center; DOE/OSTI
  2. City Univ. of New York (CUNY), NY (United States). The Mount Sinai Medical and Graduate Schools. Dept. of Physiology; Brookhaven National Lab. (BNL), Upton, NY (United States). The Medical Research Center
+ Show Author Affiliations

A sensitive and precise method for assaying the water permeability response evoked by neurohypophyseal hormones and their synthetic analogues on the isolated urinary bladder of the toad (Bufo marinus L.) is described. The method permits detection of 8-arginine-vasotocin at concentrations as low as 10-12M. This sensitivity, not achieved heretofore with this tissue, results largely from minimizing interference of inhibitory substances by means of an "in vitro circulation assembly." The precision of the method derives from a direct comparison between the cumulative dose-response curve of an agonist of unknown potency acting on one hemibladder and that of a reference compound acting on the contralateral hemibladder. Crystalline deamino-oxytocin is used as the reference standard in this assay. The intrinsic activity of 2-(O-methyltyrosine)-oxytocin, as defined by the maximal response, is 12% lower than that of deamino-oxytocin. All other hormonal peptides investigated have the same intrinsic activity as deamino-oxytocin, even 5-valine-oxytocin, in spite of its extremely low affinity. A comparison of the potencies of 8-arginine-vasotocin vs. 8-arginine-vasopressin, 8-ornithine-vasotocin vs. 8-ornithine-vasopressin, 8-alanine-oxytocin vs. 8-alanine-oxypressin, and deamino-8-alanine-oxytocin vs. deamino-8-alanine-oxypressin suggests that an isoleucine residue in position 3 imparts a higher specificity for binding of the hormonal peptide molecule to the bladder receptor than a phenylalanine residue in this locus.

Research Organization:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Biological and Environmental Research (BER). Biological Systems Science Division
Grant/Contract Number:
AC02-98CH10886
OSTI ID:
1629142
Journal Information:
Journal of General Physiology, Journal Name: Journal of General Physiology Journal Issue: 3 Vol. 52; ISSN 0022-1295
Publisher:
Rockefeller University PressCopyright Statement
Country of Publication:
United States
Language:
English

Similar Records

Threshold and Receptor Reserve in the Action of Neurohypophyseal Peptides. A study of synergists and antagonists of the hydroosmotic response of the toad urinary bladder
Journal Article · Sat Aug 01 00:00:00 EDT 1970 · Journal of General Physiology · OSTI ID:1629139
Covalent labeling of hydrosmotic toad bladder receptors with an antagonist of vasotocin
Journal Article · Mon Jun 01 00:00:00 EDT 1987 · Am. J. Physiol.; (United States) · OSTI ID:6467469
Electrophysiological and autoradiographical evidence of V1 vasopressin receptors in the lateral septum of the rat brain
Journal Article · Sat Oct 31 23:00:00 EST 1987 · Proc. Natl. Acad. Sci. U.S.A.; (United States) · OSTI ID:5786381

Related Subjects

59 BASIC BIOLOGICAL SCIENCES