VARIATIONS IN INSULIN SENSITIVITY IN SPONTANEOUSLY HYPERTENSIVE RATS FROM DIFFERENT SOURCES

We investigated the possibility of variations in the genetic transmiss ion of insulin sensitivity in the offspring of spontaneously hypertens ive rats (SHRs) and Wistar Kyoto rats (WKYs) obtained from different s ources (Charles River, Tokyo, Japan [NCrj]; and Funabashi Farm, Chiba, Japan [Izm]) with the insulin suppression test (IST) using a somatost atin analog, glucose, and insulin. The steady-state blood glucose (SSB G) in the IST and the glucose infusion required (GIR) in the euglycemi c-hyperinsulinemic clamp differ significantly between obese and lean Z ucker rats, indicating that both methods are useful for identifying in sulin resistance. The fasting blood glucose and SSBG of the IST were s ignificantly higher in SHR/Izm than in WKY/Izm, We did not observe a s ignificant difference between SHR/NCrj and WKY/NCrj. These results ind icate that the genetic transmission of hypertension and impaired insul in sensitivity may be variable and that insulin resistance does not pl ay an important role in the pathogenesis of hypertension in the SHR. C opyright (C) 1998 by W.B. Saunders Company.