ABSTRACT
Vasoconstrictor and Na/K pump inhibitory properties of a bufodienolide Na/K-ATPase inhibitor, marinobufagenin, were studied in isolated rings of 2 to 3 order branches of human pulmonary arteries respectively. Marinobufagenin displayed concentration-dependent vasoconstrictor activity (0.01 to 10 mmol/L). In sarcolemma membranes prepared from pulmonary artery marinobufagenin inhibited Na/K-ATPase (IC50 = 50 nmol/L). In eight healthy male Caucasians, concentrations of marinobufagenin-like immunoreactive material in C-18 extracted plasma were 1.38 +/- 0.60 nmol/L. Twenty-four-hour urinary release of marinobufagenin-like immunoreactive material in eight healthy males was 1.20 +/- 0.95 nmol/day. Chloroform extract of human urine was fractionated using reverse-phase high-performance liquid chromatography (32% acetonitrile, Deltapak). The HPLC fraction coeluting with marinobufagenin in 7 min, cross reacted with antimarinobufagenin and antidigoxin, but not antiouabain antibody. These results demonstrate that human plasma and urine contains a bufodienolide vasoconstrictor EDLF, marinobufagenin-like immunoreactive Na,K pump inhibitor.
Subject(s)
Bufanolides/immunology , Enzyme Inhibitors/immunology , Pulmonary Artery/physiology , Vasoconstrictor Agents/immunology , Bufanolides/analysis , Bufanolides/pharmacology , Enzyme Inhibitors/analysis , Enzyme Inhibitors/pharmacology , Humans , Male , Pulmonary Artery/drug effects , Sodium-Potassium-Exchanging ATPase/antagonists & inhibitors , Vasoconstriction/drug effects , Vasoconstrictor Agents/analysis , Vasoconstrictor Agents/pharmacologyABSTRACT
In order to reduce the influence of hydrogen bonds on the acylamino acid salts attachment to the chloromethylated resin, it is proposed to use compounds that can compete for the hydrogen bonds formation. The best solvent proved to be hexamethylphosphoric triamide. Use of interphase catalysts, e.g., tributyl-p-nitrobenzyl ammonium, also gives good results. The racemization degree of the amino acids attached to solid support by means of the interphase catalysis does not exceed that of amino acids loaded on the polymer according to Gisin's method.
