EFFECT OF PROLONGED HYPOXIA UPON GRANULARITY OF RENAL JUXTAGLOMERULAR CELLS

The various experimental models used in previous studies of the juxtaglomerular apparatus do not permit the effect of changes in oxygen tension of the renal parenchyma to be separated from that of changes in distension of the renal arterial bed. To study the isolated effect of prolonged hypoxia, three groups of rats, matched for weight, were kept in low oxygen, room air, and high oxygen environment for two weeks. The animals were pair-fed with the hypoxic rats serving as the determinant group. Supplemental injections of sodium chloride were given daily to avoid the effect of sodium deprivation on the juxtaglomerular cells. It was found that the hematocrits and also the granularity of the juxtaglomerular cells were significantly increased in the hypoxic rats as compared to the other two groups. Blood pressures, serum sodium levels, and urinary excretion of sodium were comparable among the three groups. These findings demonstrate that increased granularity of the renal juxtaglomerular cells can be induced by prolonged hypoxia.