[Effect of prenatal gamma-irradiation on functional properties of rat liver adenylate cyclase].

In the present work the effects of long-term prenatal gamma-irradiation (0.5 Gy) on the glucagon signalling through adenylyl cyclase have been investigated. In utero gamma-irradiation resulted in the increase of basal and GTP-stimulated adenylyl cyclase activity, whereas, the adenylyl cyclase response to glucagon was essentially reduced. The comparison of kinetic constants estimated from dose-response data for GTP and glucagon suggests that prenatal chronic irradiation prompted (i) the decrease in rate of GTP hydrolysis on Gs-protein; (ii) the reduction of glucagon potency to accelerate the exchange GDP for GTP on Gs-protein.