Effect of pregnancy on insulin metabolism in spontaneously hypertensive rats

Several lines of evidence suggest that insulin resistance and/or hyperinsul inemia may play an important role in the pathogenesis of hypertension. We s tudied the effect of pregnancy on insulin metabolism in spontaneously hyper tensive rats (SHRs) and in Wistar-Kyoto rats (WKYs) as a control. Pregnancy markedly reduced blood pressure in both strains of rats, but insulin resis tance as determined by the hyperinsulinemic glucose clamp (10 mU/kg/min) in creased in SHRs and was unchanged in WKYs. The plasma insulin response to a n intravenous glucose challenge in SHRs was low and did not change with pre gnancy. Therefore, it is suggested that the regulation of blood pressure in these animals is linked to an unknown factor rather than to insulin resist ance and hyperinsulinemia. Fetuses from SHRs had a lower body weight and pl asma glucose level and higher plasma insulin and pancreatic insulin levels than those from WKYs. Thus, fetal hyperinsulinemia in the SHR may be linked to the development of hypertension in adulthood. Copyright (C) 1999 by W.B . Saunders Company.