Establishment and use of the M strain of stroke-prone spontaneously hypertensive rat.

An inbred strain of stroke-prone spontaneously hypertensive rat, the M-SHRSP, was established by brother-sister breeding of selected SHRSP for 24 generations while administering apresoline. Compared with SHRSP, the M-SHRSP shows an earlier rise in blood pressure, plasma renin activity (PRA) and cerebrospinal fluid (CSF) pressure, and somewhat changed cerebrovascular lesions. Crosses and back-crosses, using M-SHRSP, Wistar-Kyoto rats (WKY), spontaneously hypercholesterolaemic (SHC) rats and their hybrids produced colonies with various blood pressure levels and hypercholesterolaemia. Continued successive selective brother-sister breeding of M-SHRSP and SHC hybrids produced a colony with severe hypertension and marked hypercholesterolaemia. Streptozotocin diabetes was induced in an M-SHRSP and SHC hybrid (TC), from which diabetic TC was successively bred to the fifth generation. While each generation was hypertensive and showed a decrease in islet B-cells, symptoms of lasting glycosuria were first observed in the fourth generation among those given a high alpha-corn starch (75.7%) diet.