Relationship between serum or tissue ouabain and blood pressure in 1k1c hypertensive rats

Objective To evaluate the role of endogenous ouabain (EO) in the developmen t of hypertension and the characteristics of EO secretion in 1k1c (one kidn ey, one clipped) hypertensive rats. Methods EO content of serum and tissues in 1k1c hypertensive rats and norma l control Sprague-Dawley (SD) rats was detected by the method of enzyme lin ked immunosorbent assay (ELISA). The relationship between serum or tissue o uabain and blood pressure was analyzed in 1k1c hypertensive rats. Results The ouabain content of serum, heart, kidney, adrenal gland, pituita ry and hypothalamus was significantly higher in 1k1c hypertensive rats than that in normal control SD rats (2.25, 2.63, 3.35, 40.37, 3.34, 15.7 mu g/k g tissue in 1k1c hypertensive rats vs 1.12, 1.79, 1.73, 27.54, 1.83, 10.10 mu g/kg tissue in control SD rats, respectively. P < 0.05 for all of these comparisons). The ouabain content of the adrenal gland and the hypothalamus was higher than that of other tissues or serum, both in 1k1c rats and in c ontrol SD rats. The EO content of serum, kidney and hypothalamus was signif icantly correlated with blood pressure in 1k1c hypertensive rats (r = 0.59, 0.63, 0.52, respectively. P < 0.05). The ouabain content of heart, liver, adrenal gland and pituitary was not correlated with blood pressure. Conclusions EO might play an important role in the development of hypertens ion in 1k1c hypertensive rats. The adrenal gland may be a major source of E O and the hypothalamus-pituitary-adrenal axis may be involved in the regula tion of EO secretion.