The adrenal cortex in spontaneously hypertensive rats. A quantitative ultrastructural study.

The adrenal cortex of spontaneously hypertensive rats (SHR) has been examined by quantitative morphologic techniques for electron microscopy. The volume and surface area of smooth endoplasmic reticulum and the volume of Golgi apparatuses in zona glomerulosa cells of SHR was significantly greater than those of Wistar-Kyoto strain (W/KY) normotensive controls; the volume of lipid droplets and nucleus was significantly less in SHR than in W/KY animals. A stimulation of the zona glomerulosa in SHR may well be attributable to the elevation in systolic blood pressure. A distinct lipid-free subglomerulosa was observed in the adrenal gland of W/KY rats; the cell volume was similar to that of the zona glomerulosa although the cells showed a significantly greater volume of mitochondria and surface area of mitochondrial membranes and greater volume of smooth endoplasmic reticulum and lysosomes. In the zona fasciculata, cell volume, volumes and surface area of mitochondria and smooth endoplasmic reticulum, and volume of lipid droplets were significantly lower in SHR than in W/KY rats. The volume of the Golgi apparatus was greater in SHR than in W/KY rats. Glycogen particles were observed in focal areas of some zona fasciculata cells. The adrenal cortex of another strain of normotensive Wistar rat (W/CFN) was compared with that of the W/KY and SHR. Although the relative adrenal weights of SHR and W/KY animals were identical, the weight of that in W/CFN was significantly smaller. The volume of the zona glomerulosa of SHR was significantly greater than that of W/KY although the volume of the zona glomerulosa in W/CFN was significantly greater than the other two groups. The volume of nucleus and lipid droplets of zona glomerulosa in W/KY was significantly greater than that in the S/CFN; the volume of the cell, mitochondria, smooth endoplasmic reticulum, lipid droplets, and lysosomes, and the surface area of smooth endoplasmic reticulum and mitochondrial membranes of W/KY animals was significantly greater than those of W/CFN animals. It is concluded that the W/CFN rat is not an appropriate control for spontaneously hypertensive rats.