Development and regulation of hypertension in the spontaneously hypertensive rat: enzymatic and nutritional studies

Abstract

Essential human hypertension is a multifactorial disease. Genetic, dietary and environmental influences contribute to the development and maintenance of hypertension (Meneely and Battarbee, 1976; Paul, 1977). The several strains of rat which become hypertensive in a spontaneous but highly predictable fashion are recognized as the most appropriate experimental models for the investigation of essential hypertension (Folkow and Hallback, 1977). The most widely used of these strains is the Spontaneously Hypertensive Rat (SHR) developed by Okamoto and Aoki in the early 1960’s by selective inbreeding of slightly hypertensive individuals from a large population of normotensive rats of the Wistar-Kyoto substrain (WKY) (Okamoto, 1969). The development and maintenance of hypertension in the SHR resembles hypertension in the human in that: 1) The developing or “labile” phase in the SHR occurs before the animal is mature whereupon a secondary, slower increase in blood pressure continues throughout the SHR’s life. 2) The life span of the SHR is abbreviated by about one third when compared to its normotensive progenitor, the WKY. 3) The cause of death in the SHR has generally been due to end-organ damage consequent to the elevated blood pressure.