[Morphological studies into pulmonary arterioles in pregnant rabbits with experimental hypertension (author's...

Arterial hypertension was evoked in pregnant rabbits by daily applications of 2.5 microgram/kg/min of CIBA hypertensin, beginning on the 16th day of pregnancy. The animals were sacrificed on the 30th day of pregnancy. Pathological changes were histological recorded from their pulmonary arterioles, particularly those between 100 and 400 micron in outer diameter. They were vascular contraction, hyperplasia of exterior and central vascular layers, oedema, elastosis as well as fibrinous and hyaline proliferation. Non-pregnant rabbits, which had received the same dose of hypertensin, died on the third day from application. Their pulmonary arterioles were found to have undergone contraction. No vascular changes were recordable from clinically intact pregnant rabbits.