Pathophysiological studies on hypertension induced in rats by kidney extract and salt

The renin-angiotensin-aldosterone system, electrolyte and water balance, body fluid, and neurogenic tone and reactivity of the vasculature were studied in hypertension induced in uninephrectomized rats by repeated injection of renin-rich kidney extract and 1% saline drinking. The control rats were injected with physiological saline. Various measurements were made in conscious rats on the 10th day of the treatment. As compared with the control, plasma renin concentration and serum sodium increased significantly, while plasma aldosterone and renal excretory function did not differ. Blood volume (BV) expressed as per body weight increased significantly, but absolute BV, absolute or body weight-related plasma volume and hematocrit were not significantly different. The hypotensive effect of 1-Sar-8-Ile-angiotensin II was negligible 12 hours after the preceding injection of kidney extract. It was small but significant 1 hour after the injection. Increase in water turn-over and fractional sodium excretion occurred during the development of hypertension. Spironolactone did not significantly modify the developmental course. We observed increased depressor response to hexamethonium and increased reactivities to noradrenaline and angiotensin II (A II); these response curves relatively resembled those of spontaneously hypertensive rats. Hypertensive vascular changes were seen in the kidney and heart by histology. Thus, it was suggested that a direct vascular action of A II played a partial role in this hypertensive process while aldosterone played little role. The significance of BV increase and possible contribution of A II's other actions were discussed.

Zymogram analyses of various organs, glands and tissues from spontaneously hypertensive rats (SHR) and DOCA hypertensive rats

Esterase and Acid phosphatase isozymes were examined in a number of organs, glands and tissues from Spontaneously Hypertensive Rats (SHR) and kidney and liver from DOCA hypertensive rats at various stages in comparison with those of normotensive rats (CR). In SHR, the abnormalities in the patterns of esterase isozyme were demonstrated in endocrine glands and respiratory tracts as well as in the kidney, liver and digestive tracts throughout the whole life span, and abnormalities in the patterns of acid phosphatase isozyme was also demonstrated in the liver after seven days of age. Moreover, in DOCA hypertensive Rats, minute alterations in esterase isozyme were demonstrated in the kidney and liver after seventh month of the duration of hypertension.