Spontaneous hypertension and hypertensive renal disease in the fawn-hooded rat.

The fawn-hooded (FH) rat, a strain characterized by a platelet storage-pool disease, developed focal and segmental glomerulosclerosis at the age of 2-3 months (males) and approximately 6 months (females). Male animals died spontaneously at 11-13 months, and females at 15 months of age, both with overt malignant nephrosclerosis. During the first half year of life focal glomeruli showed depositions of IgG, IgA, IgM, C3 and fibrinogen in a segmental pattern and mainly in mesangial areas. Mesangial IgG and IgA were already demonstrable at the age of 5 weeks. On electron microscopy no electron-dense deposits suggestive of immune complexes were found. Mean arterial blood pressure in 5.5-month-old male FH rats was increased compared with that of matched Wistar rats. One-year-old FH rats had severe hypertension. The presumed relationship between the hypertension, the renal lesions and the blood platelet defect is discussed.