Vena Caval Constriction Research Articles

DEMONSTRATION BY PRESSOR AND STEROIDOGENIC ASSAYS OF INCREASED RENIN IN LYMPH OF DOGS WITH SECONDARY HYPERALDOSTERONISM.

Thoracic duct lymph from normal dogs and from dogs with hyperaldosteronism secondary to thoracic inferior vena caval constriction was assayed for renin. After acidification, dialysis and incubation, lymph from animals with caval constriction showed more angiotensin-like material than lymph of normal dogs when assayed for both pressor and aldosterone-stimulating activities. Nephrectomy was followed by a marked decrease or disappearance of renin activity from lymph. Lymph from dogs with renal venous hypertension secondary to abdominal vena caval constriction did not show increased renin content. Dual assay makes detection of angiotensin II more specific and the findings indicate that increased amounts of renin are released from the kidney into lymph of dogs with experimental secondary hyperaldosteronism.

CORTICOSTEROID SECRETION FOLLOWING CAVAL CONSTRICTION IN DOGS WITH ISOLATED PITUITARIES1

The output per minute of 17-hydroxycorticostcroids was measured before and after partial thoracic inferior vena caval constriction in normal dogs and those with brain removal and isolated pituitaries. The “resting” control 17-hydroxycorticosteroid output was higher in dogs with brain removal than in normal animals. Both groups of dogs demonstrated a significant increase in corticosteroid output following caval constriction. It is concluded that partial constriction of the thoracic inferior vena cava is a strong stimulus to ACTH release.