An ultrastructural, morphometric and autoradiographic study of the effects of 7,12-dimethylbenzanthracene on the rat adrenal cortex.

The effects of chronic treatment (up to 9 consecutive days) with 7,12-dimethylbenzathracene (DMBA) on the adrenal glands of adult male Wistar rats were investigated. Morphometry showed that DMBA provokes atrophy of the zona reticularis which was due to the decrease in both cell volume and number. The zona fasciculata showed only a decrease in the cell volume, whereas the zona glomerulosa did not display any significant changes. Autoradiography demonstrated that DMBA induces a significant increase in the number of mitoses and "S" phase cells in the zona glomerulosa and outer zona fasciculata, which may be interpreted as a repair mechanism of the DMBA-provoked slight necrosis in the inner adrenocortical layers. The mechanism(s) underlying the cytotoxic effect of DMBA is discussed in the light of our ultrastructural observations showing that the chemical causes a decrease in the volume of the mitochondrial and nuclear compartments and in the surface of smooth endoplasmic reticulum as well as an increase in the volume of the lipid compartment.