Since the survival-shortening activity of some vegetable oils, including canola and hydrogenated soybean oil, was reported in stroke-prone spontaneously hypertensive rats (SHRSP), several studies have been carried out to identify the causatives, but without success. We evaluated changes in pathophysiological parameters in several strains of rats caused by canola and/or hydrogenated soybean oil to help identify the causatives. No single target organ was found for canola oil, but several changes were observed in the parameters. That is, a diet containing 10% canola oil, which shortens the life of SHRSP and similar survival-shortening is also caused by hydrogenated soybean oil, increased blood pressure; decreased platelet counts; enhanced blood coagulation; increased hepatic glucose-6-phosphate dehydrogenase activity, with an elevation of plasma lipids; altered Na&sup+;, K&sup+;-ATPase activities; decreased antioxidant enzyme activities; and increased plasma aldosterone levels, with a decrease in plasma and/or testicular testosterone levels in several strains of rats. Moreover, histochemical examinations revealed increased expression of cyclooxygenase 2 in macula densa cells in the kidney. In this review, the physiological and pathological changes are summarized in relation to canola oil-induced exacerbation of the hypertension-related conditions in SHR and SHRSP. In addition, possible involvement of dihydro-vitamin K1-like substance is discussed in relation to the observed changes.
