Effects of blood pressure reduction on the ultrastructure of the adrenal cortex of the spontaneously hypertensive rat.

Antihypertensive drugs were given to 25-week-old spontaneously hypertensive rats (SHR) and Wistar Kyoto rats, and the animals were sacrificed at 45-47 weeks of age. The effects of the decreased blood pressure on the adrenal zona glomerulosa and zona fasciculata were studied ultrastructurally and morphometrically. It was found that both groups of animals responded to the lower blood pressure in a similar manner, but the ability to respond is structurally compromised in the zona glomerulosa of SHR. This malfunction may be congenital in origin.