In order to determine the general patterns of activation of the inter organ compensatory-adaptive processes, the peculiarities of activation of compensatory processes caused by unilateral nephrectomy in adult rat liver at the initial stage of hepatopathy (first three days after the operation) have been studied. In particular, it has been established that only small but visible abnormalities in the spatial relationship of sinusoids and hepatic plates are revealed morphologically in rat liver histology. The increasing of the functional load caused by changes in histoarchitecture, at these times, does not stimulate hepatocyte proliferation. At the same time, it is revealed that at the initial stage of hepatopathy caused by unilateral nephrectomy, preference is given to polyploidy from compensatory-adaptive processes charachterised to liver. In particular, it has been shown that liver responses mainly by quantitative increases in binucleated cells (2cx2) to the functional load induced by unilateral nephrectomy at an early stage.