Infarct-kidney hypertension in the rat mutant nude

Infarct-kidney hypertension was induced in congenital athymic nude rats, and in their immunologically normal haired littermates. In both groups a significant initial increase in blood pressure was seen in the course of the first 30 days. In the remainder of the observation period of 120 days the mean blood pressure in the nude rats decreased to a significantly lower level where-as in the haired rats the mean blood pressure remained unchanged at the high level. Although a high mortality weakened the results, it is hypothesized that the failing ability to maintain the elevated blood pressure into the late phase in the nude rats could be due to impaired thymus function. Nine of 14 haired rats had increased numbers of lymphocytes around intrarenal arteries, in contrast to only 1 of 10 nude rats. A periarteritis nodosa like picture was observed around mesenterial arteries of 3 nude and 2 haired rats. The level of plasma renin was similar preoperatively in nude and haired rats. Infarction of the kidney was followed by a significant decrease in the plasma renin level in both nude and haired rats, which at 10 days was significantly lower in haired than in nude rats, despite a higher blood pressure in the latter.