A comparative morphometric analysis of the effects of thyroxine and ACTH on the zona fasciculata of rat adrenal cortex.

The effects of thyroxine and ACTH on the ultrastructure of cells of the adrenal zona fasciculata were studied by morphometric analysis and compared by two-way analysis of variance. The results indicate that the effects of thyroxine and ACTH are different and independent. The statistically significant differences in effect of thyroxine and ACTH are: thyroxine causes an increase in the volume fraction of mitochondria and a decrease in the volume fraction of endoplasmic reticulum independent of ACTH; thyroxine causes a decrease in surface density of mitochondria and endoplasmic reticulum in the absence of ACTH, but in the presence of ACTH this effect is moderated by an interaction of throxine and ACTH. There were no statistically significant effects of either thyroxine or ACTH on volume fraction or surface density of liposomes.