Beschreibung:
<jats:title>Abstract</jats:title><jats:p>The light and electron microscopic appearances of the human juxtaglomerular apparatus in benign essential and malignant (accelerated phase) hypertension are described. In the former, the variability of appearances precludes assessment of the importance of the apparatus in the pathogenesis or progression of the disease. The hyperplastic appearance of the apparatus in malignant hypertension supports the concept of renin hypersecretion in this phase. Mechanisms of JGA stimulation are considered and the possibility of a new source of renin discussed. It is suggested that morphological appraisal of cellular activity could be correlated with chemical estimations, allowing a clearer delineation of the role of the renin‐angiotensin system in the pathogenesis and progression of benign and malignant hypertension. This might be of value in assessing the cellular response to various specific pharmacological agents used in the management of these conditions.</jats:p>