[Desensitization as a reflection of receptor-enzyme system inactivation during a reaction. Kinetic model of the process].

The kinetic regularities of the processes occurring in the system: receptor-adenylate cyclase complex under the effect of a hormone, an agonist or a neuromediator, were studied. Experiments with cell cultures revealed that the effector caused an impulse increase in cAMP and a decrease in the effector-stimulated activity of the adenylate cyclase complex. The above effects were considered within the framework of a kinetic model which takes into account the enzyme complex inactivation in the course of adenylate cyclase synthesis. The data obtained permit to explain the physiological effect of desensitization of the receptor-enzyme system with respect to the effector action as a result of inactivation of this system in the course of the reaction. Possible molecular mechanisms of inactivation are discussed.