Hypertension was induced in rats by either renal artery stenosis or a fructose-enriched diet, and the consequent changes in plasma glucose, insulin, and triglyceride (TG) concentrations, and the steady-state plasma insulin (SSPI) and glucose (SSPG) concentrations in response to a 180-min continuous infusion of glucose and insulin in these two groups of hypertensive rats, were compared to values in a sham-operated group with normal blood pressure. Mean (+/- SEM) blood pressure was significantly higher than the control values (121 +/- 3 mm Hg) at the end of the study in rats with renal artery stenosis (178 +/- 13 mm Hg) and fructose-fed rats (151 +/- 5 mm Hg), whereas left ventricular weight was only significantly (P < .01) higher in rats with renal artery stenosis. Plasma glucose concentration was the same in all three groups, but fructose-fed rats had significantly higher plasma insulin (59 +/- 7 microU/mL) and TG (317 +/- 48 mg/dL) concentration than either sham-operated rats (30 +/- 4 microU/mL and 121 mg/dL) or rats with renal artery stenosis (34 +/- 5 microU/mL and 124 +/- 14 mg/dL). Although SSPI concentrations were similar (approximately 250 microU/mL) in all three groups of rats, SSPG concentrations were significantly higher (P < .01) in the fructose-fed rats (187 +/- 10 mg/dL) than in either sham-operated normotensive rats (120 +/- 6 mg/dL) or hypertensive rats with renal artery stenosis (133 +/- 4 mg/dL). Thus, insulin resistance, hyperinsulinemia, and hypertriglyceridemia developed in rats with fructose-induced hypertension, whereas none of these changes were seen in rats with renal artery stenosis.