Ultrastructural investigation of renomedullary interstitial cells in "endocrine kidney".

In the renomedullary interstitial cells of rats with Selye's "endocrine kidney" in the phase of beginning hypertension there appeared bilateral stress hypergranulation and an ultrastructural pattern of intensive prostaglandin synthesis. In the interstitial tissue of the left medulla there appeared light and dense (fibroblast- or macrophage-like) cells. Along with the stabilization of hypertension a relative degranulation of interstitial cells in the right kidney and an absolute degranulation in the left kidney took place. Necrobiotic changes, appearing in the ischaemic kidney, reflected an exhaustion of morphological substrates of prostaglandin synthesis. The changes in the interstitial cells, possessing endocrine activity, present the decisive links in the genesis of experimental malignant hypertension in rats.