[Age-related morphofunctional characteristics of the adrenal cortical substance when ACTH is administered]

The structural and morphometric features of the adrenocortical substance (ACS) were investigated in adult (5 mos.) and aged (24 mos.) albino male rats during single and prolonged ACTH administration (Synachten-Depot, Ciba). In single administration of a large dose of ACTH (50 micrograms per 100 g of body mass) to adult rats hypertrophy of ACS secretory cells was marked to a greater extent (by 105.9%), and the area of ACS cell nuclei was increased after the administration of a smaller dose of ACTH (25 micrograms per 100 g of body mass). In old animals the administration of a smaller dose of the hormone resulted in an increased area of nuclei and cytoplasm of ACS cells (by 55%). In prolonged administration of the hormone during 14 days an increase in the sizes of nuclei and cytoplasm of ACS cells was observed both in adult and aged rats. However in the adrenal glands of old rats, cell hypertrophy was less marked than that in adult animals (134 and 186.2%, respectively) and was accompanied by destructive changes in a portion of cells. In 95% the results of morphometry were obtained in the confidence interval using a Leitz-ASM unit (FRG) for semiautomatic image analysis. The differences were statistically significant.