Adenosine-deaminase activity of myocardium homogenates of normal rats and rats pretreated with dipiridamole

Abstract

It has been studied the adenosin-desaminase activity in myocardium homogenates from normal rats and pre-treated with dipiridamol. The enzyme is inhibited by the drug and it seems to be competitive. At the two concentrations used (50 µg and 100 µg per g weight), the inhibition is 13 % and 27.5 %, respectively. The Km of the enzyme for the normal rats is 2.2 X 10-4 M. In the treated animals, the Km is 2.8 X 10-4 M or 4 X 10-4 M.

This inhibitory effect could explain the coronary dilatator action of the dipiridamol. Finally, these data are related with the results obtained in vitro from the previous experiments.