Further Studies of Angiopathic Serum Factor in Perinephritic Hypertensive Dogs

Abstract

The serum of perinephritic hypertensive dogs causes waterlogging and increased sodium (Na) content of rabbit aorta explants in tissue culture. In the present study, we investigated the role of tissue glycosaminoglycans in the pathogenesis of these changes. The effect of ouabain and prostaglandin F2α on the composition of rabbit aorta explants in tissue culture was studied to determine if they produced alterations that were similar to those produced by the serum of hypertensive dogs. Rabbit aortic media explants were cultured in tissue culture medium supplemented (15–20%) with serum obtained from 12 dogs during a pre-hypertension control period and after induction of one-kidney, one-wrapped hypertension. After 3 weeks of culture, the explants were harvested, and their Na, potassium (K) and hexosamine content was measured. Compared to the composition of explants cultured in pre-hypertension control serum, the water and Na content of explants cultured in the serum of hypertensive dogs was increased (p < 0.02 and p < 0.01). There were no differences in the K and hexosamine content of explants cultured in the two sera. There was a dose-dependent increase in the Na content and a reduction in the K content of explants cultured in the presence of ouabain (5 × 10^-8 to 5 × 10^-7M) and PGF2α (1 μg/ml). The findings of this study provide further evidence for angiopathic serum factor(s) in perinephritic hypertensive dogs. The excess Na of explants cultured in the serum of hypertensive dogs does not appear to be bound to glycosaminoglycans. The accumulation of excess Na is not due to an ouabain-like mechanism.