Hypoxic Moderation of Renal Hypertension in the Miniature Swine

Abstract

Eleven male Yucatan miniature swine were subjected to unilateral renal artery constriction (RAC) with an intact contralateral kidney. Five pigs remained at laboratory altitude of 1524 m and served as normoxic, hypertensive controls (NH) while the other six (HH) were subjected to a simulated altitude of 4267 m for 9 weeks to determine the effect of hypoxia on the development of renal hypertension. Systemic blood pressure was increased less in HH as compared with NH. Data from three sib-pairs represented in each treatment group suggested a diverse, apparently familial response to RAC. The hypertensive process, irrespective of treatment groups, included a diminution of free circulating serum thyroxin and an increase in serum sodium. Hypoxia moderates renal hypertension in the miniature pig primarily via a decrement in stroke volume and cardiac output.