Quantitative ultrastructural study of the adrenal cortex: effects of a mammotropic pituitary tumor producing growth hormone and prolactin (MtT-W10), and of injected growth hormone in the rat.

The ultrastructure of the adrenal cortex has been examined in animals bearing a growth hormone and prolactin secreting mammotropic tumor (MtT-W 10). The large quantities of hormone secreted by the tumor caused a stimulation of zona fasciculata cells. The adrenal weight increased approximately 2-fold in tumor bearing animals. There were increases in the cellular volume of zona fasciculata cells and in the volume of mithchondria and smooth endoplasmic reticulum per cell as determined by quantitative morphometric techniques. The surface area of smooth endoplasmic reticulum and total mitochondrial membranes showed a significant increase in zona fasciculata cells as well. Injections of purified bovine growth hormone caused small but not significant increases in mitochondrial and smooth endoplasmic reticulum volumes. Growth hormone however did induce a significant increase in the surface area of mitochondrial membrane.