Sepideh P. The effect of antidiuretic hormone on bile formation in liver.

The thesis deals with the results of experimental studies about the effect of one of the antidiuretic hormone analogues - desmopressin and selective V1a vasopressin receptors antagonist on bile formation in liver. The studies about the choleresis level and chemical compositions of bile under the effect of desmopressin conducted in chronic experiments in dogs with cholecyctoduodenal fistula tubes. Investigations about the effect of the both desmopressin and the selective V1a vasopressin receptors antagonist on these components conducted in acute experiments in common bile duct cunnulated rats. It is shown the effect of these peptides on bile volume and its free- conjugated bile acids, lipid fractions contents. It was established that desmopressin at the dose of 0.1 ng/kg dogs body weight and 1 ng/100 g rats body weight influences on secreted bile volume and its organic compositions. Desmopressin stimulates markedly the cholersis volume velocity and significantly increases the absolute content of aminoacid conjugated bile acids, bile lipid fractions as phospholipids, cholesterol and its esters in bile both in rats and dogs. These results illustrate, that desmopressin stimulates the conjugation process of bile acids and lipids metabolism, especially the process of etherification of cholesterol in hepatocytes. These changes of quantitative bile compositions improve antilithogenic bile properties and decrease the potential producing of bile stones. It is noticeable that desmopressin during blocking of V1a vasopressin receptors, shows less cholerethic effect, than the effect of hormone alone. This fact clears the role of V1a vasopressin receptors in realization of desmopressin effects in bile formation procedure in liver.