Gender difference in diet-induced obesity hypertension: implication of renal 2-adrenergic receptors

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Abstract
Although the pathogenesis of the obesity-related hypertension is not fully understood, prevalence of the cardiovascular complications is much higher in obese men than obese women. In a recent study, we reported that male rats fed a cafeteria diet, while becoming obese, developed hypertension and important changes in their renal α2-adrenergic receptor subtypes distributions. The aim of the present study was to investigate whether these alterations are sex dependent. After 10 weeks of the cafeteria diet, male and female rats had the same increase in fat pad weight and in plasma leptin levels. However, in contrast to males, females had normal blood pressure (BP). On the basis of radioligand-binding studies using [3H]-RX821002 and confirming our recent observation, an increase in α2-adrenergic receptor densities occurred in kidneys of cafeteria-fed male but not female rats. Moreover, in contrast with the situation observed in males, ligand competition studies failed to reveal any change in the renal α2A- and α2B-adrenergic receptors subtypes distribution in females. Finally, in the cafeteria-fed females reverse transcription-polymerase chain reaction experiments showed unaltered expression of these two α2-adrenergic receptor subtypes. These data thus suggest a strong relationship between the sexual dimorphism in the cafeteria diet-induced hypertension and altered expression of the α2-adrenergic receptor subtypes in the kidney.